WorldWideScience

Sample records for alternating current motors

  1. Speed controller for an alternating - current motor

    International Nuclear Information System (INIS)

    A controller for a multi-phase ac motor that is subject to a large inertial load, e.g. an induction motor driving a heavy spinning rotor of a neutron chopper that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal Esub(L) having a meandering line frequency, includes a sensor which provides a feedback pulse train representative of the actual speed of the motor which is compared (by counting clock pulses between feedback pulses) with a reference clock signal in a computing unit to provide a motor control signal Esub(c). The motor control signal is a weighted linear sum of a speed error signal, a phase error signal, and a drift error signal, the magnitudes of which are recalculated and updated with each revolution of the motor shaft. The speed error signal is constant for large speed errors but highly sensitive to small speed errors. The stator windings of the motor are driven by variable-frequency power amplifiers which are controlled by the motor control signal Esub(c) via PROMs which store digital representations of sine and cosine waveforms in quadrature. (author)

  2. Alternating-Current Motor Drive for Electric Vehicles

    Science.gov (United States)

    Krauthamer, S.; Rippel, W. E.

    1982-01-01

    New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.

  3. A new system of alternating current motors and transformers and other essays

    CERN Document Server

    Tesla, Nikola

    2013-01-01

    Nikola Tesla was a genius who revolutionized how the world looks at electricity. During college his professors explained that it was impossible to design an engine without commutators or brushes. Tesla was unconvinced that such was necessary or even particularly desirable. It was then that Tesla began his work on the rotating field motor that ultimately gave birth to the modern age. In May of 1888, Tesla delivered his lecture ""A New System of Alternating Current Motors and Transformers"" before The American Institute of Electrical Engineers and the world has never been the same.

  4. Speed Control of a Three Phase Alternating Current Induction Motor Using Space Vector Pulse Width Modulation

    OpenAIRE

    Angelo A. Beltran Jr.

    2014-01-01

    Sinusoidal pulse width modulation is a popular modulation for most alternating current induction motor. It only requires fewer calculations and is easy to implement. However, the shortcomings of using it are low DC voltage utilization, and poor inverter transmission capability. In recent years, there is an increasing trend and more research concentration of using space vector pulse width modulation in adjustable speed drives and renewable energy systems because...

  5. Research on the variable speed system of large power alternating current motor%Research on the variable speed system of large power alternating current motor

    Institute of Scientific and Technical Information of China (English)

    Li Chongjian

    2012-01-01

    The development status of the variable speed system of large power AC (alternating current) motor drive in China is introduced. The large power AC drive fed by AC-AC converters (cycloconverters) has developed greatly, and some innovations on the theory and engineering technique have been realized. They have been applied to rolling mills, mine hoists, and so on, and remarkable economic and social benefit has been achieved. The development of AC drive fed by large power IGCT (integrated gate commutated thyristors) AC-DC-AC converter is also introduced. It has excellent performance and reliable operation, and has been used in traction.

  6. Digital driver of alternate current motors of the control rods in a nuclear research reactor

    International Nuclear Information System (INIS)

    The updating of the instruments as the operation console of the TRIGA Mark III Salazar Reactor is based on the use of a personal computer that works as data acquisition and control device. The power changes on the reactor have been made through the inserting or extraction of four control rods, that they are operated by mechanisms based in alternate current motors. That is with the object to handling each of the bars and so avoiding too the degradation about the performance of the computer of process. Also it is using four drives of smart kind which do the basic duties for generating the control signals and verifying the sensors state of the limits in continuous form. The computer and drivers are organized as a ring net using the serial port R S-232. The computer of process sends the orders and the identification of destination instrument throughout the net. (Author)

  7. Feedback-Controlled Transcranial Alternating Current Stimulation Reveals a Functional Role of Sleep Spindles in Motor Memory Consolidation.

    Science.gov (United States)

    Lustenberger, Caroline; Boyle, Michael R; Alagapan, Sankaraleengam; Mellin, Juliann M; Vaughn, Bradley V; Fröhlich, Flavio

    2016-08-22

    Transient episodes of brain oscillations are a common feature of both the waking and the sleeping brain. Sleep spindles represent a prominent example of a poorly understood transient brain oscillation that is impaired in disorders such as Alzheimer's disease and schizophrenia. However, the causal role of these bouts of thalamo-cortical oscillations remains unknown. Demonstrating a functional role of sleep spindles in cognitive processes has, so far, been hindered by the lack of a tool to target transient brain oscillations in real time. Here, we show, for the first time, selective enhancement of sleep spindles with non-invasive brain stimulation in humans. We developed a system that detects sleep spindles in real time and applies oscillatory stimulation. Our stimulation selectively enhanced spindle activity as determined by increased sigma activity after transcranial alternating current stimulation (tACS) application. This targeted modulation caused significant enhancement of motor memory consolidation that correlated with the stimulation-induced change in fast spindle activity. Strikingly, we found a similar correlation between motor memory and spindle characteristics during the sham night for the same spindle frequencies and electrode locations. Therefore, our results directly demonstrate a functional relationship between oscillatory spindle activity and cognition. PMID:27476602

  8. Beta band transcranial alternating (tACS and direct current stimulation (tDCS applied after initial learning facilitate retrieval of a motor sequence

    Directory of Open Access Journals (Sweden)

    Vanessa eKrause

    2016-01-01

    Full Text Available The primary motor cortex (M1 contributes to the acquisition and early consolidation of a motor sequence. Although the relevance of M1 excitability for motor learning has been supported, the significance of M1 oscillations remains an open issue. This study aims at investigating to what extent retrieval of a newly learned motor sequence can be differentially affected by motor-cortical transcranial alternating (tACS and direct current stimulation (tDCS. Alpha (10 Hz, beta (20 Hz or sham tACS was applied in 36 right-handers. Anodal or cathodal tDCS was applied in 30 right-handers. Participants learned an eight-digit serial reaction time task (SRTT; sequential vs. random with the right hand. Stimulation was applied to the left M1 after SRTT acquisition at rest for ten minutes. Reaction times were analyzed at baseline, end of acquisition, retrieval immediately after stimulation and reacquisition after eight further sequence repetitions.Reaction times during retrieval were significantly faster following 20 Hz tACS as compared to 10 Hz and sham tACS indicating a facilitation of early consolidation. TDCS yielded faster reaction times, too, independent of polarity. No significant differences between 20 Hz tACS and tDCS effects on retrieval were found suggesting that 20 Hz effects might be associated with altered motor-cortical excitability. Based on the behavioural modulation yielded by tACS and tDCS one might speculate that altered motor-cortical beta oscillations support early motor consolidation possibly associated with neuroplastic reorganization.

  9. Constant Current Models of Brushless DC Motor

    OpenAIRE

    Krykowski, Krzysztof; Hetmańczyk, Janusz

    2013-01-01

    Two constant current models of Permanent Magnet Brushless Direct Current Motor (PM BLDC) are presented in the paper. In the first part of the paper principle of operation, basic properties and mathematical equations describing PM BLDC models are given. Then, two different constant current models of PM BLDC motor are considered: In the first model, PM BLDC motor is approximated with dc motor; in the second model, modified constant current model is applied with additional block, which is used t...

  10. Bi-modes alternation stepping ultrasonic motors

    Institute of Scientific and Technical Information of China (English)

    Jiamei JIN; Chunsheng ZHAO

    2008-01-01

    Based on the principle of alternative operation of two bending vibration modes in an annular stator, this paper presents a standing-wave stepping ultrasonic motor characterized by no accumulative errors driven by an open-loop control circuitry. The driving forces are generated from the motions of projections on the stator in two modes. The positioning of the motor is achieved by the cooperation between the stator projections and rotor teeth, and the number of the rotors determines the stepping angle of the motor. Two-phase sinusoidal signals corresponding to the two modal frequencies drive the motor bi-direction stepping rotation via a switch unit. The prototype runs steadily without miss-step on trial. The single-step angle displacement of the motor is 2.5°.

  11. Alternative motor fuels today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bensaid, B

    2004-07-01

    Today, petroleum products account for 97% of the energy consumed in road transport. The purpose of replacing these products with alternative energies is to reduce oil dependence as well as greenhouse gas emissions. The high price of oil has promoted the use of 'conventional' alternative motor fuels (biofuels, LPG, NGV) and also renewed interest in syn-fuels (GTL, CTL, BTL) that have already given rise to industrial and pilot projects. (author)

  12. Alternative motor fuels today and tomorrow

    International Nuclear Information System (INIS)

    Today, petroleum products account for 97% of the energy consumed in road transport. The purpose of replacing these products with alternative energies is to reduce oil dependence as well as greenhouse gas emissions. The high price of oil has promoted the use of 'conventional' alternative motor fuels (biofuels, LPG, NGV) and also renewed interest in syn-fuels (GTL, CTL, BTL) that have already given rise to industrial and pilot projects. (author)

  13. Control strategy minimizing the converter-alternating current motor losses: application to electric traction; Strategies de commande minimisant les pertes d'un ensemble convertisseur - machine alternative: application a la traction electrique

    Energy Technology Data Exchange (ETDEWEB)

    Bastiani, Ph.

    2001-02-01

    Improving the efficiency of the converter-alternating current motor system is a major task in electric traction. Global energy optimisation implies a specific approach at system scale. To reach this goal, we have chosen an algebraic method using sub-system models. To start with, a synchronous machine Park model is developed to take account magnetic saturation and iron losses. Then, an averaged model of the voltage inverter is used in order to obtain a simplified model of the losses to be implemented in our optimisation method. This is how the global model is built including losses in the synchronous machine along with the losses of the power converter. Experimental results are there to validate our approach. This study proposes a method based on algebraic formulation of the general laws to control torque. Algorithms take into account magnetic circuits saturation and power losses in both the machine and its converter. Here again, experimental results validate the algorithm on several test benches. Achieved efficiency improvement is important compared to existing usual control strategies. The proposed method can be generalised to other machine-converter systems. As a matter of fact we have extended our study to the induction machine. As a complement ti this study we have looked at the effects natural limitations of voltages and currents in the torque-speed plane. Therefore algebraic formulation of the torque-speed plane and optimisation strategies are proposed including those constraints. (author)

  14. Brushless direct-current motors

    Science.gov (United States)

    Bahm, E. J.

    1970-01-01

    Survey results are presented on the use of unconventional motor windings and switching sequences to optimize performance of brushless dc motors. A motor was built, each coil terminal having a separate, accessible lead. With the shaft and all electronics excluded, length and outside diameter measured 1.25 and 0.75 in., respectively.

  15. Constant current electric motor drive for fan

    Energy Technology Data Exchange (ETDEWEB)

    Church, C.A.

    1988-03-23

    A motor for driving air through a replaceable filter to the face of a wearer of a protective helmet is supplied with power from a rechargeable battery pack through a current regulator which is controlled to tend to maintain the motor current constant in spite of variations in the battery voltage or the degree of clogging of the filter. The voltage across the motor, measured by resistors can be used as a measure of the degree of clogging of the filter to actuate an audible or visible alarm if the filter becomes too clogged. The voltage across the regulator measured by resistors can be used as a measure of the voltage of the battery to give a visible or audible warning if the battery charge gets too low. The two different warnings can be distinguishable from one another.

  16. Alternation of Agonists and Antagonists During Turtle Hindlimb Motor Rhythms

    OpenAIRE

    Stein, Paul S.G.

    2010-01-01

    In a variety of vertebrates, including turtle, many classical and contemporary studies of spinal cord neuronal networks generating rhythmic motor behaviors emphasize a Reciprocal Model with alternation of agonists and antagonists, alternation of excitatory and inhibitory postsynaptic potentials, and reciprocal inhibition. Some studies of spinal cord neuronal networks, including those in turtle during scratch motor rhythms, describe a Balanced Model with concurrent excitatory and inhibitory po...

  17. Reducing current reversal time in electric motor control

    Energy Technology Data Exchange (ETDEWEB)

    Bredemann, Michael V

    2014-11-04

    The time required to reverse current flow in an electric motor is reduced by exploiting inductive current that persists in the motor when power is temporarily removed. Energy associated with this inductive current is used to initiate reverse current flow in the motor.

  18. Alternating current for the West

    International Nuclear Information System (INIS)

    In the framework of the reactor EPR construction in the Manche, the authors wonder on the pertinence of this energy choice for the economy and the environment of the West France. They show that there is an alternative to this choice. In a first part a state of the situation concerning the electricity supply and demand in the region is detailed. Then from the local potential of renewable electric power production and the electricity conservation, they propose many concrete actions. (A.L.B.)

  19. ALTERNATING CURRENT ELECTROCOAGULATION FOR SUPERFUND SITE REMEDIATION

    Science.gov (United States)

    The technical and economical feasibility of alternating current electrocoagulation (ACE) developed by Electro-Pure Systems, Inc., was evaluated for a 2-year period. CE is an electrochemical technology where highly-charged aluminum polyhydroxide species are introduced into aqueous...

  20. Induction machine condition monitoring using notch-filtered motor current

    Science.gov (United States)

    Günal, Serkan; Gökhan Ece, Dog˜an; Nezih Gerek, Ömer

    2009-11-01

    This paper presents a new approach to induction motor condition monitoring using notch-filtered motor current signature analysis (NFMCSA). Unlike most of the previous work utilizing motor current signature analysis (MCSA) using spectral methods to extract required features for detecting motor fault conditions, here NFMCSA is performed in time-domain to extract features of energy, sample extrema, and third and fourth cumulants evaluated from data within sliding time window. Six identical three-phase induction motors were used for the experimental verification of the proposed method. One healthy machine was used as a reference, while other five with different synthetic faults were used for condition detection and classification. Extracted features obtained from NFMCSA of all motors were employed in three different and popular classifiers. The proposed motor current analysis and the performance of the features used for fault detection and classification are examined at various motor load levels and it is shown that a successful induction motor condition monitoring system is developed. Developed system is also able to indicate the load level and the type of a fault in multi-dimensional feature space representation. In order to test the generality and applicability of the developed method to other induction motors, data acquired from another healthy induction motor with different number of poles and rated power is also incorporated into the system. In spite of the above difference, the proposed feature set successfully locates the healthy motor within the classification cluster of "healthy motors" on the feature space.

  1. Stability of alternating current gliding arcs

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Salewski, Mirko; Leipold, Frank;

    2014-01-01

    on Ohm’s law indicates that the critical length of alternating current (AC) gliding arc discharge columns can be larger than that of a corresponding direct current (DC) gliding arc. This finding is supported by previously published images of AC and DC gliding arcs. Furthermore, the analysis shows...

  2. Experimental Study on Current Decay Characteristics of Persistent Current HTS Magnet by Alternating Magnetic Field

    Science.gov (United States)

    Park, Young Gun; Lee, Chang Young; Hwang, Young Jin; Lee, Woo Seung; Lee, Jiho; Jo, Hyun Chul; Chung, Yoon Do; Ko, Tae Kuk

    This paper deals with a current decay characteristics of a high temperature superconducting (HTS) magnet operated in persistent current mode (PCM). In superconducting synchronous machine applications such as linear synchronous motor (LSM), the superconducting coil is designed to operate in the PCM to obtain steady magnetic field with DC transport current. This superconducting magnet operates on a direct current, but it can be exposed to alternating magnetic field due to the armature winding. When the magnet is subjected to an external time-varying magnetic field, it is possible to result in a decay of the current in PCM system due to AC loss. In this research, a PCM system with armature coil which generates time-varying magnetic field was fabricated to verify current decay characteristics by external alternating magnetic field. The current decay rate was measured by using a hall sensor as functions of amplitude and frequency of armature coil.

  3. Current Pharmaceutical Treatments and Alternative Therapies of Parkinson's Disease.

    Science.gov (United States)

    Dong, Jie; Cui, Yanhua; Li, Song; Le, Weidong

    2016-01-01

    Over the decades, pharmaceutical treatments, particularly dopaminergic (DAergic) drugs have been considered as the main therapy against motor symptoms of Parkinson's disease (PD). It is proposed that DAergic drugs in combination with other medications, such as monoamine oxidase type B inhibitors, catechol-O-methyl transferase inhibitors, anticholinergics and other newly developed non-DAergic drugs can make a better control of motor symptoms or alleviate levodopa-induced motor complications. Moreover, non-motor symptoms of PD, such as cognitive, neuropsychiatric, sleep, autonomic and sensory disturbances caused by intrinsic PD pathology or drug-induced side effects, are gaining increasing attention and urgently need to be taken care of due to their impact on quality of life. Currently, neuroprotective therapies have been investigated extensively in pre-clinical studies, and some of them have been subjected to clinical trials. Furthermore, non-pharmaceutical treatments, including deep brain stimulation (DBS), gene therapy, cell replacement therapy and some complementary managements, such as Tai chi, Yoga, traditional herbs and molecular targeted therapies have also been considered as effective alternative therapies to classical pharmaceutics. This review will provide us updated information regarding the current drugs and non-drugs therapies for PD. PMID:26585523

  4. Reactor coolant pump testing using motor current signatures analysis

    Energy Technology Data Exchange (ETDEWEB)

    Burstein, N.; Bellamy, J.

    1996-12-01

    This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

  5. Direct Current Contamination of Kilohertz Frequency Alternating Current Waveforms

    OpenAIRE

    Franke, Manfred; Bhadra, Niloy; Bhadra, Narendra; Kilgore, Kevin

    2014-01-01

    Kilohertz Frequency Alternating Current (KHFAC) waveforms are being evaluated in a variety of physiological settings because of their potential to modulate neural activity uniquely when compared to frequencies in the sub-kilohertz range. However, the use of waveforms in this frequency range presents some unique challenges regarding the generator output. In this study we explored the possibility of undesirable contamination of the KHFAC waveforms by direct current (DC). We evaluated current- a...

  6. Electromechanical systems generating constant frequency alternating current

    Directory of Open Access Journals (Sweden)

    Т.А. Мазур

    2008-01-01

    Full Text Available  In the article we consider the usage of electromechanical drivers of constant speed rotation, which is based on many stepped electrodynamic reduction unit, in onboard main systems of electric supply of alternative current with constant frequency.

  7. Condition monitoring of machinery using motor current signature analysis

    International Nuclear Information System (INIS)

    Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process ''downstream'' of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given. 1 ref., 13 figs

  8. Tiling by rectangles and alternating current

    KAUST Repository

    Prasolov, M. V.

    2011-04-01

    This paper is on tilings of polygons by rectangles. A celebrated physical interpretation of such tilings by R.L. Brooks, C.A.B. Smith, A.H. Stone and W.T. Tutte uses direct-current circuits. The new approach of this paper is an application of alternating-current circuits. The following results are obtained: •a necessary condition for a rectangle to be tilable by rectangles of given shapes;•a criterion for a rectangle to be tilable by rectangles similar to it but not all homothetic to it;•a criterion for a "generic" polygon to be tilable by squares. These results generalize those of C. Freiling, R. Kenyon, M. Laczkovich, D. Rinne, and G. Szekeres. © 2010 Elsevier Inc.

  9. The causes and effects of the Alternative Motor Fuels Act

    Science.gov (United States)

    Liu, Yimin

    The corporate average fuel economy (CAFE) standard is the major policy tool to improve the fleet average miles per gallon of automobile manufacturers in the U.S. The Alternative Motor Fuels Act (AMFA) provides special treatment in calculating the fuel economy of alternative fuel vehicles to give manufacturers CAFE incentives to produce more alternative fuel vehicles. AMFA has as its goals an increase in the production of alternative fuel vehicles and a decrease in gasoline consumption and greenhouse gas emissions. This dissertation examines theoretically the effects of the program set up under AMFA. It finds that, under some conditions, this program may actually increase gasoline consumption and greenhouse gas emissions. The dissertation also uses hedonic techniques to examine whether the Alternative Motor Fuels Act (AMFA) has a significant effect on the implicit price of fuel economy and whether the marginal value of vehicle fuel efficiency changes over time. It estimates the change of implicit price in miles per gallon after the production of alternative fuel vehicles (AFVs). Results indicate that every year consumers may evaluate vehicle fuel economy differently, and that since AFVs came to the market, the marginal value of fuel economy from specific companies producing AFVs has decreased. This finding suggests that since the AMFA provides extra Corporate Average Fuel Economy (CAFE) credit for those automakers producing AFVs, the automakers can take advantage of the incentive to produce more profitable conventional vehicles and meet CAFE standards without improving the fleet fuel economy. In this way, manufacturers who produce AFVs are willing to offer a lower price for the fuel economy under the AMFA. Additionally, this paper suggests that the flexible fuel vehicles (FFVs) on the market are not significantly more expensive than comparable conventional vehicles, even if FFVs are also able to run on an alternative fuel and may cost more than conventional vehicles

  10. Motor current signature analysis for determining operational readiness of motor-operated valves (MOVs)

    International Nuclear Information System (INIS)

    Motor current signature analysis (MCSA) is a novel diagnostic process for condition monitoring of electric-motor-driven mechanical equipment (e.g., pumps, motor-operated valves, compressors, and processing machinery). The MCSA process identifies, characterizes, and trends over time the instantaneous load variations of mechanical equipment in order to diagnose changes in the condition of the equipment (e.g., due to degradation or service wear), which, if allowed to continue, may lead to failure. It monitors the instantaneous variations (noise content) in the electric current flowing through the power leads to the electric motor that drives the equipment. The motor itself thereby acts as a transducer, sensing both large and small, long-term and rapid, mechanical load variations and converting them to variations in the induced current generated in the motor windings. This motor current noise signature is detected, amplified, and further processed as needed to examine its time domain and frequency domain (spectral) characteristics. The operational principles of MCSA and the nonintrusive data collection apparatus and procedure used with MOVs will be described. Data collected from MOVs in both laboratory and in-plant environments will also be shown to illustrate the ability of MCSA to ''see'' the detailed inner workings of the valve and operator and thus to detect degraded performance at an incipient stage. (Set of 18 vugraphs)

  11. Alternating current electrocoagulation for Superfund site remediation

    International Nuclear Information System (INIS)

    A study is being conducted by Electro-Pure Systems, Inc. (EPS) under the Emerging Technology portion of the U.S. Environmental Protection Agency's (EPA's) Superfund Innovative Technology Evaluation (SITE) Program to study alternating current electrocoagulation for Superfund site remediation. Alternating current electrocoagulation has proven to be effective in agglomerating and removing colloidal solids, metals and certain organic contaminants from surrogate soils prepared from the US EPA's Synthetic Soil Matrix. Treatments under a wide range of operating conditions have enabled the optimum parameter settings to be established for multiple phase separation. Electrocoagulation enables appreciably enhanced filtration and dewatering rates to be realized for metals- and diesel fuel-spiked surrogate soil slurries; such enhancements are prompted by growth in the mean particle size of the clays and particulates from typically < 10 microns to as much as 150 microns depending on the degree of electrocoagulation. Reduction in the total suspended solids content of clays in all slurries in excess of 90% can routinely be achieved. Bench-scale experiments of the metals-spiked surrogate soils indicate that electrocoagulation preferentially concentrates soluble metals into the sludge phase; excellent metals separation (Pb, Cr, Cu, Cd) can be realized. Experiments on surrogate wastes spiked with volatile organics suggest that this technology is not capable of effecting good volatile extractions from the aqueous phase. Reductions in excess of 80% in the total organic carbon (TOC) content of the diesel fuel-spiked surrogates can, however, be achieved

  12. A New Optimal Current Excitation Scheme of Brushless DC Motor

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J. [Koje College, Koje (Korea); Park, H.W. [Korea Naval Academy, Jinhae (Korea)

    1999-10-01

    In this paper, the novel optimal excitation scheme of BLDCM producing loss-minimized ripple-free torque based on the d-q-0 reference frame is presented including 3-phase unbalanced condition. The optimized phase current waveforms that are obtained by the proposed method can be reference values and the motor winding currents are forced to track it by using the delta modulation technique. As a result, it can be shown that the proposed work provides a simple and clear way of obtaining and controlling optimal motor excitation current. Simulation and experimental results prove the validity and practical applications of the proposed control scheme. (author). 6 refs.,5 figs.

  13. A methodology for assessing the market benefits of alternative motor fuels: The Alternative Fuels Trade Model

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, P.N.

    1993-09-01

    This report describes a modeling methodology for examining the prospective economic benefits of displacing motor gasoline use by alternative fuels. The approach is based on the Alternative Fuels Trade Model (AFTM). AFTM development was undertaken by the US Department of Energy (DOE) as part of a longer term study of alternative fuels issues. The AFTM is intended to assist with evaluating how alternative fuels may be promoted effectively, and what the consequences of substantial alternative fuels use might be. Such an evaluation of policies and consequences of an alternative fuels program is being undertaken by DOE as required by Section 502(b) of the Energy Policy Act of 1992. Interest in alternative fuels is based on the prospective economic, environmental and energy security benefits from the substitution of these fuels for conventional transportation fuels. The transportation sector is heavily dependent on oil. Increased oil use implies increased petroleum imports, with much of the increase coming from OPEC countries. Conversely, displacement of gasoline has the potential to reduce US petroleum imports, thereby reducing reliance on OPEC oil and possibly weakening OPEC`s ability to extract monopoly profits. The magnitude of US petroleum import reduction, the attendant fuel price changes, and the resulting US benefits, depend upon the nature of oil-gas substitution and the supply and demand behavior of other world regions. The methodology applies an integrated model of fuel market interactions to characterize these effects.

  14. Alternating Current Influences Anaerobic Electroactive Biofilm Activity.

    Science.gov (United States)

    Wang, Xin; Zhou, Lean; Lu, Lu; Lobo, Fernanda Leite; Li, Nan; Wang, Heming; Park, Jaedo; Ren, Zhiyong Jason

    2016-09-01

    Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network. Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology. PMID:27485403

  15. Brushless DC motor Drive during Speed regulation with Current Controller

    Directory of Open Access Journals (Sweden)

    Bhikshalu Manchala

    2015-04-01

    Full Text Available Brushless DC Motor (BLDC is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling the stator phase current in a brushless DC drive are practically effective in low speed and cannot reduce the commutation torque ripple in high speed range. This paper presents the PI controller for speed control of BLDC motor. The output of the PI controllers is summed and is given as the input to the current controller. The BLDC motor is fed from the inverter where the rotor position and current controller is the input. The complete model of the proposed drive system is developed and simulated using MATLAB/Simulink software. The operation principle of using component is analysed and the simulation results are presented in this to verify the theoretical analysis.

  16. Digital current loop control of a brushless DC motor

    OpenAIRE

    Cox, Noel Patrick

    1987-01-01

    Servo control of motors has important applications m such areas as robotics, numerically controlled machines and 'fly by wire* aircraft systems. The development of high power high coercivity magnetic alloys, such as samarium cobalt, has led to the advent of the brushless dc machine, which offers a more advantageous alternative to the brush machine. The brushless DC machine eliminates the need for brush contacts, through the use of electronic commutation. It has better thermal charact...

  17. Advanced induction motor drive control with single current sensor

    Directory of Open Access Journals (Sweden)

    Adžić Evgenije M.

    2016-01-01

    Full Text Available This paper proposes induction motor drive control method which uses minimal number of sensors, providing only DC-link current as a feedback signal. Improved DC-link current sampling scheme and modified asymmetrical switching pattern cancels characteristic waveform errors which exist in all three reconstructed motor line-currents. Motor linecurrent harmonic content is reduced to an acceptable level, eliminating torque and speed oscillations which were inherent for conventional single sensor drives. Consequently, use of single current sensor and line-current reconstruction technique is no longer acceptable only for low and medium performance drives, but also for drives where priority is obtaining a highly accurate, stable and fast response. Proposed control algorithm is validated using induction motor drive hardware prototype based on TMS320F2812 digital signal processor. [Projekat Ministarstva nauke Republike Srbije, br. III 042004 and by the Provincial Secretariat for Science and Technological Development of AP Vojvodina under contract No. 114-451-3508/2013-04

  18. ESTIMATION OF THE MAIN CHARACTERISTICS OF THE TRACTION BLDC MOTOR ON THE BASIS OF VEHICLE ALTERNATOR

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2014-10-01

    Full Text Available A method of estimation of basic parameters of the BLDC motor based on the vehicle powerful alternator to convert an ordinary vehicle into a hybrid one is offered. The results of estimation of basic characteristics of the electric motor on the basis of the automobile alternator G290 are presented.

  19. Some Properties of Current Source Inverter Fed Induction Motor Drive

    Czech Academy of Sciences Publication Activity Database

    Lettl, Jiří; Frackiewicz, Z.

    Szczecin: Technical University of Szczecin, 2001, s. 657-660. ISBN 83-88764-70-5. [International Conference UEES 01 /5./. Miedzyzdroje (PL), 05.09.2001-08.09.2001] Institutional research plan: CEZ:AV0Z2057903 Keywords : induction motor * current source inverter * torque angle control Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  20. Experimental setup for the measurement of induction motor cage currents

    International Nuclear Information System (INIS)

    An experimental setup for measurement of the currents flowing in the rotor bars of induction motors during synchronous no-load tests is described in the paper. The experimental verification of the high-frequency phenomena in the rotor cage is fundamental for a deep insight of the additional loss estimation by numerical methods. The attention is mainly focused on the analysis and design of the transducers developed for the cage current measurement

  1. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well...

  2. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2001-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is then constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as...

  3. Enhanced Motor Learning Following Task-Concurrent Dual Transcranial Direct Current Stimulation

    OpenAIRE

    Karok, Sophia; Witney, Alice G.

    2013-01-01

    Objective Transcranial direct current stimulation (tDCS) of the primary motor cortex (M1) has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on...

  4. Method for On-line Estimation of Electrical Motor Parameter Variation and Current Sensor Offset for SPM Motor

    Science.gov (United States)

    Uenaka, Yutaro; Sazawa, Masaki; Ohishi, Kiyoshi; Kenji, Takahashi

    The servo system of a permanent magnet (PM) motor should always maintain fine torque and fine speed responses. Accurate motor parameter identification is necessary for the PM motor servo system because the current control system is designed by considering the electric parameters of the PM motor. However, the motor parameters vary with the age of the motor and temperature. Moreover, current sensors have offset values. When the current sensor has offset values, the PM motor servo system produces torque ripple. In order to overcome these problems, this paper proposes a new real-time estimation method for both current sensor offsets and electrical parameters (resistance Ra, inductance La, and magnetic flux φfa) of the surface permanent magnet (SPM) motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. In order to accurately estimate the motor parametera, the proposed method is using estimate currents, DC terms of sensor currents, and nominal motor parameter value. The experimental results of this study confirm that the proposed method satisfactorily estimates the current sensor offset of the U phase and V phase, as well as the electrical motor parametersRa, La, and φfa accurately.

  5. Overview of current and alternative slaughter practices

    Directory of Open Access Journals (Sweden)

    Troeger K.

    2004-01-01

    Full Text Available The conventional cattle slaughtering process includes some critical stages where a dissemination of Specified Risk Material (SRM: brain, spinal cord within or onto the carcass and within the slaughterhouse environment can occur. These processes are captive bolt stunning, removal of the head and first of all carcass splitting (sawing the spine lengthways. Captive bolt (CB stunning results in massive brain tissue damage with bleeding, and in some cases brain tissue also emerges from the CB hole. As the heart is still functioning, there is a risk of brain tissue particles being transferred v i a the blood flow to heart and lungs or even in the whole carcass. This contamination risk is actually assessed to be low, but a continuing leakage of Central Nervous System (CNS material from the captive bolt aperture in the further slaughter process may lead to direct and indirect contamination of carcass, meat and equipment. Therefore alternative stunning methods like electrical stunning or concussion stunning are discussed. A further critical point is the treatment of the head. When the head is removed, the spinal cord is cut with a knife. There is a danger of cross contamination due to spinal protein that may adhere to the knife and because of liquid cerebralis, which leaks from the foramen occipitale magnum. Further head cleaning with hand-held hoses following skinning also includes the danger of cross contamination from cleaning water or aerosol. Therefore measures regarding the safe handling of head and harvesting of head meat are proposed. The most critical point in terms of contamination of the meat surface with SRM is the currently common practise of sawing the spine vertically in the middle with hand-guided belt-type saws. A m i x t u r e of sawing residues and rinsing water (“sawing sludge” collects in the housing of the saw, and if it contains infectious material this leads to contamination of the subsequent carcasses. The most promising

  6. Development of Rotor Diagnosis Method via Motor Current Signature Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Seok; Huh, Hyung; Kim, Min Hwan; Jeong, Kyeong Hoon; Lee, Gyu Mhan; Park, Jin Ho; Park, Keun Bae; Lee, Cheol Kwon; Hur, S

    2006-01-15

    A study on motor current signature analysis has been performed to monitor a journal bearing fault due to increasing clearance. It was known that the journal bearing clearance produces side band frequencies, the supplied current frequency plus and minus rotational rotor frequency in motor current. But the existence information of the side band frequencies is not sufficient to diagnose whether the journal bearing is safe or not. Four journal bearing sets with different clearances are used to measure the side band frequency amplitude and the rotor vibration amplitude versus the journal bearing clearance. The side band frequency amplitude and the rotor vibration amplitude are increased as the journal bearing clearance is increasing. This trend assures that ASME OM vibration guide line can be applied to estimate the journal bearing clearance size. In this research, 2.5 times the reference side band amplitude is suggested as an indicator of a journal bearing fault. Further study is necessary to make out more specific quantitative relations between the side band frequency amplitude and the journal bearing clearance of a motor.

  7. A STUDY OF DC PERMANENT MAGNET MOTOR NOISE RELATED TO LINE CURRENT

    OpenAIRE

    Suriano, Candace Rogers

    1994-01-01

    Lightweight, compact and inexpensive DC permanent magnet motors are well suited for low cost high production use in industry. Unfortunately, the audible noise emanating from these motors can cause a false negative perception of the motor's quality. In cars, for example, fan motor noise can be a nuisance. The objective of this thesis is to examine the connection between motor noise and the line current wave form for a specific four pole DC permanent magnet motor. It is further concerned with i...

  8. Brushless direct-current motor with stationary armature and field

    Science.gov (United States)

    Studer, P. A.

    1970-01-01

    Electronically commutated dc motor has an active fixed field winding, and active fixed armature winding, and passive rotor. By use of brushless dc motor switching technique, motor provides continuous controllable and reversible torque without use of sliding contacts.

  9. Alternating current electromagnetic servo induction meter

    Science.gov (United States)

    Bogue, R. K.

    1968-01-01

    Electromagnetic device accurately indicates the responses of various sensors in high performance flight research aircraft to conditions encountered in flight. The device responds to sensor inputs to move a slideable armature along an indicator scale by the force of currents induced in the armature winding.

  10. Application of electric current signature analysis for three-phase induction motors

    International Nuclear Information System (INIS)

    As the motor's supply current changes with the load behavior, it is possible to analyze the motor condition through motor current signal analysis (MCSA). This paper examined the problem of the detection of the mechanical failures of the motor and its connected gear. From the result of the tests, the MCSA method is effective to monitor the dynamic model composed of motors and gear shaft. (author)

  11. Primer on Motor Fuel Excise Taxes and the Role of Alternative Fuels and Energy Efficient Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alex [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-08-26

    Motor fuel taxes were established to finance our nation’s transportation infrastructure, yet evolving economic, political, and technological influences are constraining this ability. At the federal level, the Highway Trust Fund (HTF), which is primarily funded by motor fuel taxes, has become increasingly dependent on general fund contributions and short-term reauthorizations to prevent insolvency. As a result, there are discussions at both the federal and state levels in which stakeholders are examining the future of motor fuel excise taxes as well as the role of electric and alternative fuel vehicles in that future. On July 1, 2015, six states increased their motor fuel tax rates.

  12. Current status of high temperature superconducting motor development

    International Nuclear Information System (INIS)

    A review of high temperature superconducting (HTS) motor research is presented. Expected performance and applications for these motors are described. A number of prototype motors using liquid nitrogen cooled HTS field coils have been demonstrated over the last four years. Two synchronous motors with HTS field coils were demonstrated in 1993. The latest motor utilized a rotating HTS field winding with over 600 meters of HTS wire and produced an output power exceeding five horsepower. Measured HTS winding performance as a function of motor load is presented for the two synchronous motors demonstrated in 1993

  13. Dynamics of laser-guided alternating current high voltage discharges

    Science.gov (United States)

    Daigle, J.-F.; Théberge, F.; Lassonde, P.; Kieffer, J.-C.; Fujii, T.; Fortin, J.; Châteauneuf, M.; Dubois, J.

    2013-10-01

    The dynamics of laser-guided alternating current high voltage discharges are characterized using a streak camera. Laser filaments were used to trigger and guide the discharges produced by a commercial Tesla coil. The streaking images revealed that the dynamics of the guided alternating current high voltage corona are different from that of a direct current source. The measured effective corona velocity and the absence of leader streamers confirmed that it evolves in a pure leader regime.

  14. Submerged electricity generation plane with marine current-driven motors

    Science.gov (United States)

    Dehlsen, James G.P.; Dehlsen, James B.; Fleming, Alexander

    2014-07-01

    An underwater apparatus for generating electric power from ocean currents and deep water tides. A submersible platform including two or more power pods, each having a rotor with fixed-pitch blades, with drivetrains housed in pressure vessels that are connected by a transverse structure providing buoyancy, which can be a wing depressor, hydrofoil, truss, or faired tube. The platform is connected to anchors on the seafloor by forward mooring lines and a vertical mooring line that restricts the depth of the device in the water column. The platform operates using passive, rather than active, depth control. The wing depressor, along with rotor drag loads, ensures the platform seeks the desired operational current velocity. The rotors are directly coupled to a hydraulic pump that drives at least one constant-speed hydraulic-motor generator set and enables hydraulic braking. A fluidic bearing decouples non-torque rotor loads to the main shaft driving the hydraulic pumps.

  15. Assessment of valve actuator motor rotor degradation by Fourier analysis of current waveform

    International Nuclear Information System (INIS)

    This paper presents a test report of a motor diagnostic system that uses Fourier Analysis of the motor current waveform to detect broken rotor bars in the motor or defects in the driven equipment. The test was conducted on a valve actuator motor driving a valve actuator that was in turn driving a dynamometer to measure the actuator torque output. The motor was gradually degraded by open circuiting rotor bars. The test confirmed the efficacy of the waveform analysis method for assessing motor rotor degradation and also provided data regarding the change in waveform characteristic as motor rotors are gradually degraded to failure

  16. Rotor position sensor switches currents in brushless dc motors

    Science.gov (United States)

    1965-01-01

    Reluctance switch incorporated in an induction motor is used for sensing rotor position and switching armature circuits in a brushless dc motor. This device drives the solar array system of an unmanned space satellite.

  17. Alternating current electroluminescent properties of zinc sulfide powders

    OpenAIRE

    Salimian, Alireza

    2012-01-01

    In order to investigate the alternating current electroluminescent properties of zinc sulfide powders the following experiments were conducted: synthesis of zinc sulfide phosphors (comprised of zinc, sulfur and copper dopant); thermal shocking of phosphor materials (sudden cooling, using liquid nitrogen, of phosphor particles heated up to 500oC) and analysis of their alternating current electroluminescent properties as well as studies of particle crystal structures by synchrotron and conventi...

  18. Second interim report of the Interagency Commission on Alternative Motor Fuels

    International Nuclear Information System (INIS)

    This report describes progress the commission and government agencies have made in implementing the provisions of the Alternative Motor Fuels Act of 1988, assessing the role of alternative motor fuels in the US transportation sector, and developing policies to promote the use of alternative fuels. The alternative motor-fuels policies proposed in the National Energy Strategy (NES) are described and shows how they compose an effective long-term plan to encourage the widespread use of alternative motor fuels. The progress to date of the Department of Energy (DOE) and other agencies in implementing the programs required by the AMFA is reported. A detailed scenario of future alternative-fuel use that displaces 2.5 million barrels per day (MMBD) of petroleum and a feasible path of vehicle production and fuel supply leading to that goal is described. An analytical tool for exploring and quantifying the energy market impacts of alternative fuels, the Alternative Fuels Trade Model (AFTM), is described. The AFTM provides a means of investigating the impacts of alternative fuels in interrelated world energy markets for petroleum and natural gas. Several major initiatives have recently been enacted that have important ramifications for alternative-fuels policy. The Clean Air Act Amendments of 1990 contain provisions mandating the use of nonpetroleum oxygenates in reformulated gasoline. Other provisions for much more stringent emissions standards may affect the ability of manufacturers to make and sell conventional-fuel vehicles or, at the very least, affect their cost-effectiveness in comparison to cleaner alternative-fuel vehicles (AFV's). Finally, the key areas in which technological advances could substantially improve the competitiveness of AFV technologies in the marketplace are reviewed

  19. Motor imagery in REM sleep is increased by transcranial direct current stimulation of the left motor cortex (C3).

    Science.gov (United States)

    Speth, Jana; Speth, Clemens

    2016-06-01

    This study investigates if anodal transcranial direct current stimulation (tDCS) of areas above the motor cortex (C3) influences the quantity and quality of spontaneous motor imagery experienced in REM sleep. A randomized triple-blinded design was used, combining neurophysiological techniques with a tool of quantitative mentation report analysis developed from cognitive linguistics and generative grammar. The results indicate that more motor imagery, and more athletic motor imagery, is induced by anodal tDCS in comparison to cathodal and sham tDCS. This insight may have implications beyond basic consciousness research. Motor imagery in REM sleep has been hypothesized to serve the rehearsal of motor movements, which benefits later motor performance. Electrophysiological manipulations of motor imagery in REM sleep could in the long run be used for rehabilitative tDCS protocols benefitting temporarily immobile clinical patients, especially those who cannot perform specific motor imagery tasks - such as dementia patients, infants with developmental and motor disorders, and coma patients. PMID:27079954

  20. Bearing Damage Detection of BLDC Motors Based on Current Envelope Analysis

    Science.gov (United States)

    Lee, Chun-Yao; Hsieh, Yu-Hua

    2012-12-01

    This paper proposes current envelope analysis (CEA) to analyze bearing fault signals in brushless direct current (BLDC) motors, and back propagation neural networks (BPNN) to automatically identify bearing faults. We made sample motors which contained different types of fault, recorded the current signals, and extracted the current features using CEA and Hilbert Huang transform (HHT) for BPNN fault identification. The results indicate that this approach can efficiently identify bearing faults in BLDC motors.

  1. Alternative drives for motor cars. Hybrid systems, fuel cells, alternative energy sources. 2. enl. ed.; Alternative Antriebe fuer Automobile. Hybridsysteme, Brennstoffzellen, alternative Energietraeger

    Energy Technology Data Exchange (ETDEWEB)

    Stan, Cornel [Berkeley Univ., CA (United States)]|[Paris Univ. (France)]|[Pisa Univ. (Italy)]|[Perugia Univ. (Italy)]|[Westsaechsischen Hochschule Zwickau (Germany)

    2008-07-01

    The implementation possibilities of future drive concepts - from hybrid systems comprising an electric motor and an internal combustion engine to fuel cells to alternative fuels like hydrogen or alcohol - will depend largely on quality criteria, e.g. power density, rotary momentum, acceleration characteristics, specific energy consumption, emissions of chemical substances, and noise. The boundary criteria for the introduction of realizeable concepts of alternative drives for motor cars will be defined by the availability and storability of the envisaged fuels, technical complexity, cost, safety, infrastructure and service. The book presents and analyzes the processes, drives and energy sources that can be combined in complex energy management systems for motor cars in accordance with the aforementioned criteria. Knowledge about these facts is indispensable for the development of new concepts. The 2nd edition describes many new developments in car propulsion systems as well as their combinations, new energy sources, energy converters and energy stores. All contents and literature reflect the latest state of science and technology. (orig.) [German] Ueber die Realisierungsmoeglichkeiten zukuenftiger Antriebskonzepte - von Hybridsystemen Elektro-/Verbrennungsmotor ueber Brennstoffzellen bis zu alternativen Energietraegern wie Wasserstoff oder Alkohol - werden fundierte Kriterien der Qualitaet eines Antriebs entscheiden. Leistungsdichte, Drehmomentverlauf, Beschleunigungscharakteristik, spezifischer Energieverbrauch sowie Emission chemischer Stoffe und Geraeusche sind dafuer wichtige Merkmale zur Qualitaetsbeurteilung. Die Verfuegbarkeit und die Speicherfaehigkeit vorgesehener Energietraeger, die technische Komplexitaet, Kosten, Sicherheit, Infrastruktur und Service werden die Randbedingungen fuer die Einfuehrung realisierbarer Konzepte alternativer Antriebe fuer Automobile stellen. Die Uebersicht und die Analyse der Prozesse, Antriebsmaschinen und Energietraeger, die

  2. Brushless DC motor Drive during Speed regulation with Current Controller

    OpenAIRE

    Bhikshalu Manchala; T.Amar Kiran

    2015-01-01

    Brushless DC Motor (BLDC) is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM) materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling...

  3. Modeling and Simulation of Current Source Inverter Fed Synchronous Motor in Complex Frequency Domain Taking the Transition Zone From Induction Motor to Synchronous Motor Mode into Account

    Directory of Open Access Journals (Sweden)

    A.B. Chattopadhyay

    2014-02-01

    Full Text Available Modeling of synchronous motor plays a dominant role in designing complicated drive system for different applications, especially large blower fans etc for steel industries. As synchronous motor has no inherent starting torque generally it is started as an induction motor with the help of a damper winding and it pulls into synchronism under certain conditions. The present paper exactly concentrates on this particular zone of transition from induction motor to synchronous motor mode for a current source inverter fed synchronous motor drive system. Due to complexity of synchronous motor in terms of number of windings and finite amount of air gap saliency, direct modeling of such transition zone in time domain becomes cumbersome at the first instance of modeling. That is why the modeling in complex frequency domain (s-domain has been taken up using small perturbation model. Such a model clearly shows role of induction motor as noise function or disturbance function with respect to the open loop block diagram of synchronous motor. Such finding can be quantized in terms of important results and that is done in the present paper such that the results can help the designer for the successful design of a synchronous motor drive system.

  4. SIMULATION AND IMPLEMENTATION OF CURRENT CONTROL OF BRUSHLESS DC MOTOR BASED ON A COMMON DC SIGNAL

    OpenAIRE

    J.Karthikeyan; Dr.R.Dhanasekaran

    2010-01-01

    The objective of this project is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but the dc machine requires constant maintenance. But the brushless permanent magnet motors do not have brushes and so they require less maintenance only. Brushless dc motors are widely used in applications whic...

  5. 77 FR 33315 - Protection of Stratospheric Ozone: Alternative for the Motor Vehicle Air Conditioning Sector...

    Science.gov (United States)

    2012-06-06

    ... Air Conditioning Sector Under the Significant New Alternatives Policy (SNAP) Program AGENCY...) within the refrigeration and air-conditioning sector. This final rule only concerns the use of CO 2 in... their suppliers with a refrigerant option subject to use conditions for motor vehicle air...

  6. Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Brushless Direct Current (BLDC) motor is widely used in aerospace area, CNC machines and servo systems that require the high control accuracy Once the faults occur in the motor, it will cause great damage to the whole system. Mechanical faults are common in electric machines, and account for up to 50%-60% of the faults. Approximately, 80% of the mechanical faults lead to the eccentricity. So it is necessary to monitor the health condition of the motor to ensure the faults can be detected earlier and measures will be taken to imorove the reliability.

  7. Current status of gene therapy for motor neuron disease

    Institute of Scientific and Technical Information of China (English)

    Xingkai An; Rong Peng; Shanshan Zhao

    2006-01-01

    OBJECTIVE: Although the etiology and pathogenesis of motor neuron disease is still unknown, there are many hypotheses on motor neuron mitochondrion, cytoskeleton structure and functional injuries. Thus, gene therapy of motor neuron disease has become a hot topic to apply in viral vector, gene delivery and basic gene techniques.DATA SOURCES: The related articles published between January 2000 and October 2006 were searched in Medline database and ISl database by computer using the keywords "motor neuron disease, gene therapy", and the language is limited to English. Meanwhile, the related references of review were also searched by handiwork. STUDY SELECTION: Original articles and referred articles in review were chosen after first hearing, then the full text which had new ideas were found, and when refer to the similar study in the recent years were considered first.DATA EXTRACTION: Among the 92 related articles, 40 ones were accepted, and 52 were excluded because of repetitive study or reviews.DATA SYNTHESIS: The viral vectors of gene therapy for motor neuron disease include adenoviral, adeno-associated viral vectors, herpes simplex virus type 1 vectors and lentiviral vectors. The delivery of them can be achieved by direct injection into the brain, or by remote delivery after injection vectors into muscle or peripheral nerves, or by ex vivo gene transfer. The viral vectors of gene therapy for motor neuron disease have been successfully developed, but the gene delivery of them is hampered by some difficulties. The RNA interference and neuroprotection are the main technologies for gene-based therapy in motor neuron disease. CONCLUSION : The RNA interference for motor neuron disease has succeeded in animal models, and the neuroprotection also does. But, there are still a lot of questions for gene therapy in the clinical treatment of motor neuron disease.

  8. A Hydraulic Motor-Alternator System for Ocean-Submersible Vehicles

    Science.gov (United States)

    Aintablian, Harry O.; Valdez, Thomas I.; Jones, Jack A.

    2012-01-01

    An ocean-submersible vehicle has been developed at JPL that moves back and forth between sea level and a depth of a few hundred meters. A liquid volumetric change at a pressure of 70 bars is created by means of thermal phase change. During vehicle ascent, the phase-change material (PCM) is melted by the circulation of warm water and thus pressure is increased. During vehicle descent, the PCM is cooled resulting in reduced pressure. This pressure change is used to generate electric power by means of a hydraulic pump that drives a permanent magnet (PM) alternator. The output energy of the alternator is stored in a rechargeable battery that powers an on-board computer, instrumentation and other peripherals.The focus of this paper is the performance evaluation of a specific hydraulic motor-alternator system. Experimental and theoretical efficiency data of the hydraulic motor and the alternator are presented. The results are used to evaluate the optimization of the hydraulic motor-alternator system. The integrated submersible vehicle was successfully operated in the Pacific Ocean near Hawaii. A brief overview of the actual test results is presented.

  9. The Mechanism Study of Alternating Arc(AC)Magnetic Levitation Induction Motor

    OpenAIRE

    Li Zeng; Fan Zhang; Zhida Zhu; Fang Chen

    2015-01-01

    Magnetic levitation (no bearings) motor by using magnetic force to make rotor suspend and drive realize its high or ultra-high speed rotating. The stator’s structure of traditional no bearing magnetic levitation motor is double winding which is polar logarithmic difference 1 of 2 sets of winding (torque winding and suspension winding) and embedded in the stator. Using two inverter respectively for the two sets of winding to go into the same frequency current in order to realize the suspension...

  10. Study on Current Sensorless Vector Control Method for Electric Vehicle Drive Motor

    Directory of Open Access Journals (Sweden)

    Xiaoyong Shen

    2013-07-01

    Full Text Available With the aggravation of environment pollution and the reduction of petroleum resources, the development of electric vehicle (EV draws more and more people’s attention. In the EV research field, that seeking for a high efficient and reliable motor control method that suits the operating conditions and characteristics of the vehicle drive motor has become one of the key techniques that need to be broken through urgently. Owing to the problems that the efficient work area is narrow and it leads to over-current phenomenon when traditional motor vector control method is applied to vehicle drive motor, this paper presents a current sensorless vector control technique for electric vehicle drive motor. According to motor speed and command torque which is gained from the speed loop control, this method directly controls the magnitude and phase angle of voltage vector to realize the orientation control of the magnetic field and then achieve the purpose of controlling the motor torque and speed. The feasibility and effectiveness of this method are verified by simulation results and bench test. Moreover, this method can not only improve the efficient work area, but also increase the reliability of motor control system. At the same time, it overcomes the dependence on the current sensor, circumvents the over-current defect caused by traditional motor vector control approach and reduces its cost. So it is a suitable and efficient control method for electric vehicle drive motor.  

  11. The Mechanism Study of Alternating Arc(ACMagnetic Levitation Induction Motor

    Directory of Open Access Journals (Sweden)

    Li Zeng

    2015-01-01

    Full Text Available Magnetic levitation (no bearings motor by using magnetic force to make rotor suspend and drive realize its high or ultra-high speed rotating. The stator’s structure of traditional no bearing magnetic levitation motor is double winding which is polar logarithmic difference 1 of 2 sets of winding (torque winding and suspension winding and embedded in the stator. Using two inverter respectively for the two sets of winding to go into the same frequency current in order to realize the suspension of the rotor and motor’s driven, small carrying capacity of motor’s structure, controlling complex system. This paper based on the traditional motor technology puts forward a kind of arc principle and respectively decorates two arc motors in horizontal and vertical direction symmetric to rotor according to the electromagnetic bearing suspension technology that is constituted the arc magnetic levitation induction motor. Establishing air-gap transformation regular between rotor and stator (air-gap length motor is under the effect of interference. Based on the electromagnetic theory establishing distribution regular of the air-gap magnetic induction intensity. Virtual displacement principle is used to establish electromagnetism mathematical model and motor electromagnetism levitation. By the finite element analysis carrying on simulation research to the magnetic induction intensity, electric magnetic levitation force and distribution features of electromagnetic torque and so on.

  12. How transcranial direct current stimulation can modulate implicit motor sequence learning and consolidation: A brief review

    Directory of Open Access Journals (Sweden)

    Branislav eSavic

    2016-02-01

    Full Text Available The purpose of this review is to investigate how transcranial direct current stimulation (tDCS can modulate implicit motor sequence learning and consolidation. So far, most of the studies have focused on the modulating effect of tDCS for explicit motor learning. Here, we focus explicitly on implicit motor sequence learning and consolidation in order to improve our understanding about the potential of tDCS to affect this kind of unconscious learning. Specifically, we concentrate on studies with the serial reaction time task (SRTT, the classical paradigm for measuring implicit motor sequence learning. The influence of tDCS has been investigated for the primary motor cortex, the premotor cortex, the prefrontal cortex, and the cerebellum. The results indicate that tDCS above the primary motor cortex gives raise to the most consistent modulating effects for both implicit motor sequence learning and consolidation.

  13. How Transcranial Direct Current Stimulation Can Modulate Implicit Motor Sequence Learning and Consolidation: A Brief Review.

    Science.gov (United States)

    Savic, Branislav; Meier, Beat

    2016-01-01

    The purpose of this review is to investigate how transcranial direct current stimulation (tDCS) can modulate implicit motor sequence learning and consolidation. So far, most of the studies have focused on the modulating effect of tDCS for explicit motor learning. Here, we focus explicitly on implicit motor sequence learning and consolidation in order to improve our understanding about the potential of tDCS to affect this kind of unconscious learning. Specifically, we concentrate on studies with the serial reaction time task (SRTT), the classical paradigm for measuring implicit motor sequence learning. The influence of tDCS has been investigated for the primary motor cortex, the premotor cortex, the prefrontal cortex, and the cerebellum. The results indicate that tDCS above the primary motor cortex gives raise to the most consistent modulating effects for both implicit motor sequence learning and consolidation. PMID:26903837

  14. Electrical Characteristics of an Alternating Current Plasma Igniter in Airflow

    Science.gov (United States)

    Zhao, Bingbing; He, Liming; Du, Hongliang; Zhang, Hualei

    2014-04-01

    The electrical characteristics of an alternating current (AC) plasma igniter were investigated for a working gas of air at atmospheric pressure. The discharge voltage and current were measured in air in both breakdown and stable combustion processes, respectively, and the current-zero phenomena, voltage-current (V-I) characteristics were studied for different working gas flow rates. The results indicated that the working gas between anode and cathode could be ionized to generate gas discharge when the voltage reached 8 kV, and the maximum current was 33.36 A. When the current came to zero, current-zero phenomena appeared with duration of 2 μs. At the current-zero moment, dynamic resistance between electrodes became extremely high, and the maximum value could reach 445 kΩ, which was the main factor to restrain the current. With increasing working gas flow rates, the gradient of V-I characteristic curves was increased, as was the dynamic resistance. At a constant driven power, the discharge voltage increased.

  15. Electrical Characteristics of an Alternating Current Plasma Igniter in Airflow

    International Nuclear Information System (INIS)

    The electrical characteristics of an alternating current (AC) plasma igniter were investigated for a working gas of air at atmospheric pressure. The discharge voltage and current were measured in air in both breakdown and stable combustion processes, respectively, and the current-zero phenomena, voltage-current (V-I) characteristics were studied for different working gas flow rates. The results indicated that the working gas between anode and cathode could be ionized to generate gas discharge when the voltage reached 8 kV, and the maximum current was 33.36 A. When the current came to zero, current-zero phenomena appeared with duration of 2 μs. At the current-zero moment, dynamic resistance between electrodes became extremely high, and the maximum value could reach 445 kΩ, which was the main factor to restrain the current. With increasing working gas flow rates, the gradient of V-I characteristic curves was increased, as was the dynamic resistance. At a constant driven power, the discharge voltage increased. (plasma technology)

  16. Brushless Direct Current Motor Control Using Sensorless Single-signal Feedback

    OpenAIRE

    2006-01-01

    This report is a study into the use of a novel Compound back Electromotive Force (CBEMF) method for driving brushless direct current (BLDC) motors. The study was conducted in an attempt to find a simpler drive-method that would allow fast motor rotation with less powerful microcontrollers. The results show this method to be viable, and that further study may be beneficial. CBEMF signal is a composite signal containing feedback information from all 3 motor phases. By utilizing the CBEMF p...

  17. A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications

    OpenAIRE

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active harmonic mitigation methods have been developed over the years, the total cost and complexity has become the main obstacle in employing prior-art methods for motor drive systems. This paper presents a no...

  18. DSPIC BASED POWER ASSISTED STEERING USING BRUSHLESS DIRECT CURRENT MOTOR

    Directory of Open Access Journals (Sweden)

    G. R.P. Lakshmi

    2013-01-01

    Full Text Available This study illustrates the Electrically Assisted power Steering (EAS using BLDC motor for a vehicle. Earlier the Electrically Assisted power Steering (EAS was implemented with DSP. This study shows the usage of a dsPIC to control the BLDC motor with an encoder. The BLDC motor here is driven by dsPIC through a three phase inverter system. IRAMS type of inverter is used which is cost efficient and space efficient. The dsPIC supplied with the input of the steering. In its higher capacity the vehicles speed controller acts as the assistance level controller for steering effort. At the lower capacity, the torque controller gives the effort level control. In reality this can be realized as torque sensor and vehicle sensor interfaced in the dsPIC. For actual implementation in the system, a dsPIC-based BLDC motor controller with three-phase inverter module is used with Hall-effect sensor feedback. It is designed in such a way that the driver assistance can be varied at any time without any difficulty.

  19. Transcranial Alternating Current and Random Noise Stimulation: Possible Mechanisms

    Science.gov (United States)

    Antal, Andrea; Herrmann, Christoph S.

    2016-01-01

    Background. Transcranial alternating current stimulation (tACS) is a relatively recent method suited to noninvasively modulate brain oscillations. Technically the method is similar but not identical to transcranial direct current stimulation (tDCS). While decades of research in animals and humans has revealed the main physiological mechanisms of tDCS, less is known about the physiological mechanisms of tACS. Method. Here, we review recent interdisciplinary research that has furthered our understanding of how tACS affects brain oscillations and by what means transcranial random noise stimulation (tRNS) that is a special form of tACS can modulate cortical functions. Results. Animal experiments have demonstrated in what way neurons react to invasively and transcranially applied alternating currents. Such findings are further supported by neural network simulations and knowledge from physics on entraining physical oscillators in the human brain. As a result, fine-grained models of the human skull and brain allow the prediction of the exact pattern of current flow during tDCS and tACS. Finally, recent studies on human physiology and behavior complete the picture of noninvasive modulation of brain oscillations. Conclusion. In future, the methods may be applicable in therapy of neurological and psychiatric disorders that are due to malfunctioning brain oscillations. PMID:27242932

  20. Experimental Investigations on PV Powered SVM-DTC Induction Motor without AC Phase Current Sensors

    OpenAIRE

    T. Muthamizhan; Ramesh, R.

    2014-01-01

    The paper presents a low-cost, phase-current reconstruction algorithm for space vector modulated direct torque controlled induction motor using the information obtained from only one shunt resistor which is in series with low side switches in a conventional three-phase inverter. The aim is to develop a low-cost high - performance induction motor drive. It uses the dc-link voltage and dc current to reconstruct the stator currents needed to estimate the motor flux and the electromagnetic torque...

  1. Filtering and Control of High Speed Motor Current in a Flywheel Energy Storage System

    Science.gov (United States)

    Kenny, Barbara H.; Santiago, Walter

    2004-01-01

    The NASA Glenn Research Center has been developing technology to enable the use of high speed flywheel energy storage units in future spacecraft for the last several years. An integral part of the flywheel unit is the three phase motor/generator that is used to accelerate and decelerate the flywheel. The motor/generator voltage is supplied from a pulse width modulated (PWM) inverter operating from a fixed DC voltage supply. The motor current is regulated through a closed loop current control that commands the necessary voltage from the inverter to achieve the desired current. The current regulation loop is the innermost control loop of the overall flywheel system and, as a result, must be fast and accurate over the entire operating speed range (20,000 to 60,000 rpm) of the flywheel. The voltage applied to the motor is a high frequency PWM version of the DC bus voltage that results in the commanded fundamental value plus higher order harmonics. Most of the harmonic content is at the switching frequency and above. The higher order harmonics cause a rapid change in voltage to be applied to the motor that can result in large voltage stresses across the motor windings. In addition, the high frequency content in the motor causes sensor noise in the magnetic bearings that leads to disturbances for the bearing control. To alleviate these problems, a filter is used to present a more sinusoidal voltage to the motor/generator. However, the filter adds additional dynamics and phase lag to the motor system that can interfere with the performance of the current regulator. This paper will discuss the tuning methodology and results for the motor/generator current regulator and the impact of the filter on the control. Results at speeds up to 50,000 rpm are presented.

  2. Conventional alternating-current generators and engine generator sets

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1978-04-01

    Available data and techniques relevant to the selection and analysis of appropriate electrical generating equipment for application in the ICES program are presented. Of the general classes of commercially available a-c generators, the synchronous, rotating field alternator is most suited to ICES applications, and the focus of this technology evaluation. Conventional 60-Hz, alternating-current generators, with standard ratings ranging from 1.25 kVA to 10,000 kVA at voltages from 125 single-phase to 14,400 volts three-phase and speeds up to 1800 rpm are covered. Technical data for representative diesel engine-generator sets for continuous prime power ratings up to 6445 kW are presented. Approximate 1976 costs of standard electrical generating equipment are given for: (1) standard conventional alternating current generators and (2) packaged engine-generator sets. The data indicate a decrease in unit costs as the power ratings increase, with the cost of the slow-speed units somewhat greater than that of the higher speed units. Maintenance data for a typical total energy plant presently in operation indicate that the average cost of maintenance amounts to 41 cents/kWh. A plot of available data also indicates a trend to decreasing operating costs with increasing unit size.

  3. Cheaper Synthesis Of Multipole-Brushless-dc-Motor Current

    Science.gov (United States)

    Alhorn, Dean C.; Howard, David E.

    1994-01-01

    Circuit converts output of single two-phase shaft-angle resolver to that of multi-speed three-phase shaft-angle resolver. Converter circuit applicable to generation of multispeed, multiphase shaft-angle-resolver signals from single two-phase shaft-angle resolver. Combination of converter circuit and single two-phase shaft-angle resolver offer advantages in cost, weight, size, and complexity. Design readily adaptable to two-phase motor.

  4. Palliative care for patients with motor neurone disease: current challenges

    OpenAIRE

    Oliver, David

    2016-01-01

    David J Oliver 1Wisdom Hospice, Rochester, 2University of Kent, Canterbury, UK Abstract: Motor neurone disease is a progressive disease, and the patient and his/her family face many challenges during the disease progression, with increasing weakness and multiple losses of function. The provision of care for these patients and their families is equally challenging, anticipating and responding to the person's needs. There are increasing challenges as more is understood about the diseas...

  5. Palliative care for patients with motor neurone disease: current challenges

    OpenAIRE

    Oliver DJ

    2016-01-01

    David J Oliver 1Wisdom Hospice, Rochester, 2University of Kent, Canterbury, UK Abstract: Motor neurone disease is a progressive disease, and the patient and his/her family face many challenges during the disease progression, with increasing weakness and multiple losses of function. The provision of care for these patients and their families is equally challenging, anticipating and responding to the person's needs. There are increasing challenges as more is understood about the disease an...

  6. A Study on New Current Controller for 7-Phase BLDC Motor Drive System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Surk; Jeon, Ywun Seok; Mok, Hyung Soo [Konkuk University (Korea); Kim, Duk Keun [Komotek Co., Ltd. (Korea)

    2001-04-01

    Recently, the demand of motor for industrial, household machinery is increasing. As Switching devices and control technology are progressing, so the use of BLDC Motor is increasing. But 3-phase BLCD Motor generally used has pulsating torque and speed variation in commutation, so the range of its application is limited to high speed operation. Especially, to solve these problems, it is necessary to increase phase of Motor, so study of Poly-Phase BLDC Motor is progressing. However, when hysteresis current controller is used, switching frequency is highly increasing. In this paper, 7-Phase BLDC Motor drive system is designed. Also MSTC (Minimum Switching Time Controller) is proposed and with simulation and experiment, their validities are verified. (author). 10 refs., 26 figs., 1 tab.

  7. Analysis of torque-current characteristic of brushless DC motor driven by three-phase H-bridge

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the simulation and analysis of the steady state characteristic of a brushless DC motor studies the torque-current characteristic of the motor as well and discusses the design of a current-measure circuit for torque controlling.

  8. Speed Control Analysis of Brushless DC Motor Based on Maximum Amplitude DC Current Feedback

    OpenAIRE

    Hassan M.A.A.; Abdullah A.R.; Bahari N.

    2014-01-01

    This paper describes an approach to develop accurate and simple current controlled modulation technique for brushless DC (BLDC) motor drive. The approach is applied to control phase current based on generation of quasi-square wave current by using only one current controller for the three phases. Unlike the vector control method which is complicated to be implemented, this simple current modulation technique presents advantages such as phase currents are kept in balance and the current is con...

  9. Renal perfusion evaluation by alternating current biosusceptometry of magnetic nanoparticles

    Science.gov (United States)

    Quini, Caio C.; Matos, Juliana F.; Próspero, André G.; Calabresi, Marcos Felipe F.; Zufelato, Nicholas; Bakuzis, Andris F.; Baffa, Oswaldo; Miranda, José Ricardo A.

    2015-04-01

    Alternating current susceptometry, a simple and affordable technique, was employed to study the sensitivity of this approach to assess rat kidney perfusion by the injection of 200 μL of magnetic nanoparticles with a concentration of 23 mg/mL in the femoral vein and the measurement of the signal above the kidney. The instrument was able to detect the signal and the transit time of the first and second pass were measured in five animals with average values of 13.6±4.3 s and 20.6±7.1 s.

  10. Thin-film Josephson junctions with alternating critical current density

    Science.gov (United States)

    Moshe, Maayan; Kogan, V. G.; Mints, R. G.

    2009-01-01

    We study the field dependence of the maximum current Im(H) in narrow edge-type thin-film Josephson junctions with alternating critical current density. Im(H) is evaluated within nonlocal Josephson electrodynamics taking into account the stray fields that affect the difference of the order-parameter phases across the junction and therefore the tunneling currents. We find that the phase difference along the junction is proportional to the applied field, depends on the junction geometry, but is independent of the Josephson critical current density gc , i.e., it is universal. An explicit form for this universal function is derived for small currents through junctions of the width W≪Λ , the Pearl length. The result is used to calculate Im(H) . It is shown that the maxima of Im(H)∝1/H and the zeros of Im(H) are equidistant but only in high fields. We find that the spacing between zeros is proportional to 1/W2 . The general approach is applied to calculate Im(H) for a superconducting quantum interference device with two narrow edge-type junctions. If gc changes sign periodically or randomly, as it does in grain boundaries of high- Tc materials and superconductor-ferromagnet-superconductor heterostructures, Im(H) not only acquires the major side peaks, but due to nonlocality the following peaks decay much slower than in bulk junctions.

  11. Start Up Current Control of Buck-Boost Convertor-Fed Serial DC Motor

    OpenAIRE

    Yusuf SÖNMEZ; Mahir DURSUN; GÜVENÇ, Uğur; Cemal YILMAZ

    2009-01-01

    Generally, DC motors are given preference for industrial applications such as electric locomotives, cranes, goods lifts. Because of they have high starting moment; they initially start with high current. This high start-up current must be decreased since it may damage windings of the motor and increases power consumption. It could be controlled by an appropriate driver system and controller. The nature of fuzzy logic control has adaptive characteristics that can achieve robust response to a s...

  12. An Alternating Current Electroosmotic Pump Based on Conical Nanopore Membranes.

    Science.gov (United States)

    Wu, Xiaojian; Ramiah Rajasekaran, Pradeep; Martin, Charles R

    2016-04-26

    Electroosmotic flow (EOF) is used to pump solutions through microfluidic devices and capillary electrophoresis columns. We describe here an EOF pump based on membrane EOF rectification, an electrokinetic phenomenon we recently described. EOF rectification requires membranes with asymmetrically shaped pores, and conical pores in a polymeric membrane were used here. We show here that solution flow through the membrane can be achieved by applying a symmetrical sinusoidal voltage waveform across the membrane. This is possible because the alternating current (AC) carried by ions through the pore is rectified, and we previously showed that rectified currents yield EOF rectification. We have investigated the effect of both the magnitude and frequency of the voltage waveform on flow rate through the membrane, and we have measured the maximum operating pressure. Finally, we show that operating in AC mode offers potential advantages relative to conventional DC-mode EOF pumps. PMID:27046145

  13. A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active...... harmonic mitigation methods have been developed over the years, the total cost and complexity has become the main obstacle in employing prior-art methods for motor drive systems. This paper presents a novel current modulation method based on the electronic inductor concept for three-phase ac-dc systems to...

  14. Alternating current electrospinning for preparation of fibrous drug delivery systems.

    Science.gov (United States)

    Balogh, Attila; Cselkó, Richárd; Démuth, Balázs; Verreck, Geert; Mensch, Jürgen; Marosi, György; Nagy, Zsombor Kristóf

    2015-11-10

    Alternating current electrospinning (ACES) was compared to direct current electrospinning (DCES) for the preparation of drug-loaded nanofibrous mats. It is generally considered that DCES is the solely technique to produce nanofibers using the electrostatic force from polymer solutions, however, less studied and also capable ACES provides further advantages such as increased specific productivities. A poorly water-soluble drug (carvedilol) was incorporated into the fibers based on three different polymeric matrices (an acid-soluble terpolymer (Eudragit(®) E), a base-soluble copolymer (Eudragit(®) L 100-55) and a nonionic homopolymer (polyvinylpyrrolidone K90)) to improve the dissolution of the weak base drug under different pH conditions. Morphology and fiber diameter evaluation showed similar electrospun fibers regardless the type of the high voltage and the major differences in feeding rates. The amorphous ACES and DCES fibers provided fast and total drug dissolutions in all cases. The presented results show that ACES can be a more feasible novel alternative to formulate fibers for drug delivery purposes. PMID:26320549

  15. Alternative drives for motor cars. Hybrid systems, fuel cells, alternative energy sources. 3. ed.; Alternative Antriebe fuer Automobile. Hybridsysteme, Brennstoffzellen, alternative Energietraeger

    Energy Technology Data Exchange (ETDEWEB)

    Stan, Cornel [California Univ., Berkeley, CA (United States); Paris-1 Univ., 75 (France); Pisa Univ. (Italy); Perugia Univ. (Italy); Kronstadt Univ. (Russian Federation)

    2012-07-01

    This book describes and assesses on the basis of the latest research and development projects worldwide what the possibilities are for the realisation of future drive concepts, ranging from battery-driven electromotors to hybrid systems combining electromotor and combustion engine to alternative energy resources such as hydrogen or alcohol. Power density, torque band, acceleration characteristics, specific energy consumption and chemical and noise emissions are the most important criteria for assessing the quality of a drive configuration. The boundary conditions for the introduction of alternative automotive drives are determined by the availability or production characteristics and the storability of the energy resources in question as well as by the degree of technical complexity, costs, safety, infrastructure and service. This book provides an updated overview and analysis of the processes, prime movers and energy resources that can be combined in complex energy management systems for automobiles. Up-to-date information of this kind is indispensable for the development of new concepts. The contents in overview: current data and facts on the development of new concepts; compact overview and analysis of processes, prime movers and energy resources; methods and solutions in designing alternative drives. [German] Die Realisierungsmoeglichkeiten zukuenftiger Antriebskonzepte - von batteriebetriebenen Elektromotoren und Hybridsystemen bestehend aus Elektro- und Verbrennungsmotor ueber Brennstoffzellen bis hin zu alternativen Energietraegern wie Wasserstoff oder Alkohol - werden auf Basis neuesten Forschungs- und Entwicklungsarbeiten weltweit praesentiert und bewertet. Leistungsdichte, Drehmomentverlauf, Beschleunigungscharakteristik, spezifischer Energieverbrauch sowie Emission chemischer Stoffe und Geraeusche sind wichtige Merkmale zur Beurteilung der Qualitaet einer Antriebskonfiguration. Die Verfuegbarkeit oder die Herstellungsmerkmale sowie die Speicherfaehigkeit

  16. Diagnosis of cryogenic pump-motor systems using vibration and current signature analysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byeong Keun; Gu, Dong Sik; Kim, Hyo Jung; Jeong, Han Eul [Gyeongsang National University, Tongyoung (Korea, Republic of); Kim, Hak Eun [Korea Gas Technology Corporation, Tongyoung (Korea, Republic of)

    2006-07-15

    In general, to send out natural gas via a pipeline network across the nation in LNG terminal, high-pressure cryogenic pump supply highly compressed LNG to high-pressure vaporization facilities. The Number of cryogenic pumps determined the send-out amount in LNG receiving terminal. So it is main equipment at LNG production process and should be maintained on best conditions. In this paper, to find out the cause of high vibration at cryogenic pumps-motor system in LNG terminal, vibration spectrum analysis and motor current signature analysis have been performed together. Through the analysis, motor rotor bar problems are estimated by the vibration analysis and confirmed by the current analysis. So, it is demonstrated through the case study in this paper, how performing vibration analysis and current signature analysis together can reliable diagnosis rotor bar problems in pump-motor system.

  17. Real-time control for long ohmic alternate current discharges

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.

    2014-05-15

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks.

  18. Real-time control for long ohmic alternate current discharges

    International Nuclear Information System (INIS)

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks

  19. Mountain Plains Learning Experience Guide: Electric Motor Repair.

    Science.gov (United States)

    Ziller, T.

    This Electric Motor Repair Course is designed to provide the student with practical information for winding, repairing, and troubleshooting alternating current and direct current motors, and controllers. The course is comprised of eight units: (1) Electric Motor Fundamentals, (2) Rewinding, (3) Split-phase Induction Motors, (4) Capacitor Motors,…

  20. Inter-individual variability in optimal current direction for transcranial magnetic stimulation of the motor cortex

    DEFF Research Database (Denmark)

    Balslev, Daniela; Braet, Wouter; McAllister, Craig; Miall, R Chris

    We evaluated inter-individual variability in optimal current direction for biphasic transcranial magnetic stimulation (TMS) of the motor cortex. Motor threshold for first dorsal interosseus was detected visually at eight coil orientations in 45 degrees increments. Each participant (n=13) completed...... intensity and side-effects it may be worthwhile to check whether rotating the coil 45 degrees from the traditional posterior-lateral orientation decreases motor threshold....... two experimental sessions. One participant with low test-retest correlation (Pearson's r<0.5) was excluded. In four subjects, visual detection of motor threshold was compared to EMG detection; motor thresholds were very similar and highly correlated (0.94-0.99). Similar with previous studies...

  1. Current error vector based prediction control of the section winding permanent magnet linear synchronous motor

    International Nuclear Information System (INIS)

    Highlights: → The structure of the permanent magnet linear synchronous motor (SW-PMLSM) is new. → A new current control method CEVPC is employed in this motor. → The sectional power supply method is different to the others and effective. → The performance gets worse with voltage and current limitations. - Abstract: To include features such as greater thrust density, higher efficiency without reducing the thrust stability, this paper proposes a section winding permanent magnet linear synchronous motor (SW-PMLSM), whose iron core is continuous, whereas winding is divided. The discrete system model of the motor is derived. With the definition of the current error vector and selection of the value function, the theory of the current error vector based prediction control (CEVPC) for the motor currents is explained clearly. According to the winding section feature, the motion region of the mover is divided into five zones, in which the implementation of the current predictive control method is proposed. Finally, the experimental platform is constructed and experiments are carried out. The results show: the current control effect has good dynamic response, and the thrust on the mover remains constant basically.

  2. Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Sophia Karok

    Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

  3. Alternative donor transplants for severe aplastic anemia: current experience.

    Science.gov (United States)

    Bacigalupo, Andrea; Sica, Simona

    2016-04-01

    Patients with acquired severe aplastic anemia (SAA), who lack a human leukocyte antigen (HLA) identical sibling donor (SIB), have two therapeutic options: immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporine (CsA), or a transplant from an alternative donor. In these patients, the current guidelines of the European Group for Blood and Marrow Transplantation (EBMT) call for a course of ATG + CsA first and transplantation in case of no response. The alternative donor source can be an unrelated donor (UD), a cord blood (CB) unit, or a family mismatched member, in most instances genetically HLA haplo-mismatched (HAPLO). In the present review, we will discuss recent results of transplants from matched UD and SIB donors, with significantly improved outcome, especially with UD in the past decade. We will also be looking at CB transplants, and the problems of limited stem cell dose. Finally HAPLO grafts have been explored in patients lacking or having rejected an unrelated or CB graft: early results seem encouraging, though the procedure should still be considered experimental. PMID:27000736

  4. Alternatives to animal testing: current status and future perspectives.

    Science.gov (United States)

    Liebsch, Manfred; Grune, Barbara; Seiler, Andrea; Butzke, Daniel; Oelgeschläger, Michael; Pirow, Ralph; Adler, Sarah; Riebeling, Christian; Luch, Andreas

    2011-08-01

    On the occasion of the 20th anniversary of the Center for Alternative Methods to Animal Experiments (ZEBET), an international symposium was held at the German Federal Institute for Risk Assessment (BfR) in Berlin. At the same time, this symposium was meant to celebrate the 50th anniversary of the publication of the book "The Principles of Humane Experimental Technique" by Russell and Burch in 1959 in which the 3Rs principle (that is, Replacement, Reduction, and Refinement) has been coined and introduced to foster the development of alternative methods to animal testing. Another topic addressed by the symposium was the new vision on "Toxicology in the twenty-first Century", as proposed by the US-National Research Council, which aims at using human cells and tissues for toxicity testing in vitro rather than live animals. An overview of the achievements and current tasks, as well as a vision of the future to be addressed by ZEBET@BfR in the years to come is outlined in the present paper. PMID:21607681

  5. Renal perfusion evaluation by alternating current biosusceptometry of magnetic nanoparticles

    International Nuclear Information System (INIS)

    Alternating current susceptometry, a simple and affordable technique, was employed to study the sensitivity of this approach to assess rat kidney perfusion by the injection of 200 μL of magnetic nanoparticles with a concentration of 23 mg/mL in the femoral vein and the measurement of the signal above the kidney. The instrument was able to detect the signal and the transit time of the first and second pass were measured in five animals with average values of 13.6±4.3 s and 20.6±7.1 s. - Highlights: • Rat kidney transit time of magnetic nanoparticles was measured with biosusceptometry. • AC biosusceptometry has sensitivity to measure magnetic nanoparticles in rat kidney. • AC susceptometry has good potential for in vivo studies of magnetic nanoparticles

  6. Alternating-current relaxation of a rotating metallic particle

    Science.gov (United States)

    Guo-Xi, Nie; Wen-Jia, Tian; Ji-Ping, Huang; Guo-Qing, Gu

    2016-06-01

    Based on a first-principles approach, we establish an alternating-current (AC) relaxation theory for a rotating metallic particle with complex dielectric constant . Here is the real part, the conductivity, ω 0 the angular frequency of an AC electric field, and . Our theory yields an accurate interparticle force, which is in good agreement with the existing experiment. The agreement helps to show that the relaxations of two kinds of charges, namely, surface polarized charges (described by ) and free charges (corresponding to ), contribute to the unusually large reduction in the attracting interparticle force. This theory can be adopted to determine the relaxation time of dynamic particles in various fields. Project supported by the National Natural Science Foundation of China (Grant No. 11222544), the Fok Ying Tung Education Foundation (Grant No. 131008), the Program for New Century Excellent Talents in University, China (Grant No. NCET-12-0121), and the National Key Basic Research Program of China (Grant No. 2011CB922004).

  7. Transient motor current signature analysis via modulus of the continuous complex wavelet: A pattern approach

    International Nuclear Information System (INIS)

    Highlights: • Transient MCSA detects motor faults via time–frequency analysis of the current. • The modulus of the CCWT shows the current harmonics in the time–frequency plane. • The choice of the DOG as mother wavelet is made after a comparative analysis. • Each motor fault harmonics displays a different pattern in the generated image. • A commercial motor with a rotor broken bar has been used to present the method. - Abstract: In this paper a new method to perform Transient Motor Current Signature analysis (TMCSA), based on the Continuous Complex Wavelet Transform (CCWT) of the line current, is presented. TMCSA is a powerful online method for diagnosing motor faults. Unlike traditional MCSA methods, based on the Fourier Transform (FT) of the stator currents in stationary regime, it can identify not only the presence of current harmonics that are characteristic of each motor fault, but also their unique time–frequency evolution pattern. This feature greatly increases its reliability, helping to discard non-fault related harmonics like those generated by periodic loads or voltage unbalances. In the case of a machine with broken bars, the representation in the time–frequency plane of the left sideband harmonic during the startup transient (LSHst) constitutes such a clear fault pattern. Mathematical tools that are able to characterize non-stationary signals are needed in TMCSA, such as the CCWT. It is a highly redundant transformation of the current signal into the time–frequency domain, and its modulus is used in this paper to generate a high resolution graphic pattern of the fault. Experimental results obtained on a 1.1 kW three-phase squirrel-cage induction motor with broken bars are discussed

  8. Impairments of motor-cortex responses to unilateral and bilateral direct current stimulation in schizophrenia

    Directory of Open Access Journals (Sweden)

    AlkomietHasan

    2013-10-01

    Full Text Available Transcranial direct current stimulation (tDCS is a non-invasive stimulation technique that can be applied to modulate cortical activity through induction of cortical plasticity. Since various neuropsychiatric disorders are characterised by fluctuations in cortical activity levels (e.g. schizophrenia, tDCS is increasingly investigated as a treatment tool. Several studies have shown that the induction of cortical plasticity following classical, unilateral tDCS is reduced or impaired in the stimulated and non-stimulated primary motor cortices (M1 of schizophrenia patients. Moreover, an alternative, bilateral tDCS setup has recently been shown to modulate cortical plasticity in both hemispheres in healthy subjects, highlighting another potential treatment approach. Here we present the first study comparing the efficacy of unilateral tDCS (cathode left M1, anode right supraorbital with simultaneous bilateral tDCS (cathode left M1, anode right M1 in schizophrenia patients. tDCS-induced cortical plasticity was monitored by investigating motor-evoked potentials induced by single-pulse transcranial magnetic stimulation applied to both hemispheres. Healthy subjects showed a reduction of left M1 excitability following unilateral tDCS on the stimulated left hemisphere and an increase in right M1 excitability following bilateral tDCS. In schizophrenia, no plasticity was induced following both stimulation paradigms. The pattern of these results indicates a complex interplay between plasticity and connectivity that is impaired in schizophrenia patients. Further studies are needed to clarify the biological underpinnings and clinical impact of these findings.

  9. SIMULATION AND IMPLEMENTATION OF CURRENT CONTROL OF BRUSHLESS DC MOTOR BASED ON A COMMON DC SIGNAL

    Directory of Open Access Journals (Sweden)

    J.Karthikeyan

    2010-06-01

    Full Text Available The objective of this project is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but the dc machine requires constant maintenance. But the brushless permanent magnet motors do not have brushes and so they require less maintenance only. Brushless dc motors are widely used in applications which require wide range of speed and torque control because of its low inertia, fast response, high reliability and maintenance free. This current controlled technique is based on the generation of quasi- square wave currents using only one controller for the three phases. The current control strategy uses a triangular carrier for the power transistors which is simpler and more accuratethan any other options. The advantages of this technique are: a The stator currents are completely characterized by their maximum amplitude , b The three phases are controlled with the same dc component , and then the phase currents are kept at exactly the same magnitude I max, c The dc link current measurement is not required .d phase currents are kept balanced and phase over currents are eliminated.

  10. PERFORMANCE OPTIMIZATION OF LINEAR INDUCTION MOTOR BY EDDY CURRENT AND FLUX DENSITY DISTRIBUTION ANALYSIS

    OpenAIRE

    M. S. MANNA; Marwaha, S.; MARWAHA A.

    2011-01-01

    The development of electromagnetic devices as machines, transformers, heating devices confronts the engineers with several problems. For the design of an optimized geometry and the prediction of the operational behaviour an accurate knowledge of the dependencies of the field quantities inside the magnetic circuits is necessary. This paper provides the eddy current and core flux density distribution analysis in linear induction motor. Magnetic flux in the air gap of the Linear Induction Motor ...

  11. Simplified Modeling, Analysis and Simulation of Permanent Magnet Brushless Direct Current Motors for Sensorless Operation

    OpenAIRE

    E. Kaliappan; C. Chellamuthu

    2012-01-01

    Problem statement: In this study, a simplified modeling and experimental analysis of Permanent Magnet Brushless DC (PMBLDC) motors for Sensorless operation using MATLAB/SIMULINK. This model provides a mechanism for monitoring and controlling the voltage, current, speed and torque response. Approach: BLDC motor is modeled as sub-blocks. The inverter and switching function are implemented as S-function builder block. The Sensorless scheme employs direct back emf based zero crossing detection te...

  12. Bispectrum Analysis of Motor Current Signals for Fault Diagnosis of Reciprocating Compressors

    OpenAIRE

    Naid, A.; Gu, Fengshou; Shao, Yimin; Al-Arbi, Salem; Ball, Andrew

    2009-01-01

    The induction motor is the most common driver in industry and has been previously proposed as a means of inferring the condition of an entire equipment train, predominantly through the measurement and processing of power supply parameters. This has obvious advantages in terms of being non-intrusive or remote, less costly to apply and improved safety. This paper describes the use of the induction motor current to identify and quantify a number of common faults seeded on a two-st...

  13. A novel zero-current soft-switching converter for switched reluctance motor drives

    OpenAIRE

    Ching, TW; Chan, CC; Chan, MSW; Chau, KT

    1998-01-01

    A new zero-current-transition (ZCT) power converter for switched reluctance motor drive applications is presented. The proposed ZCT power converter possesses the definite advantages that both the main and auxiliary switches are operating with zero-current switching (ZCS), as well as minimum current and voltage stresses. It has a simple circuit topology, minimum component count and low cost. The ZCT technique can significantly reduce the switch-on or -off losses by forcing the current to zero ...

  14. Standard series of direct-current motors for regulated electric drives

    Science.gov (United States)

    Cholewicki, I.; Lubina, M.; Kozhevnikov, V. A.; Kochnev, A. V.; Skoda, K.; Voleskiy, E.

    1984-11-01

    A standard series of d.c. motors for electric drives with speed and torque regulation has been developed. Thyristor-type converters for machine tools with digital program control are also being developed. Meeting future goals requires modification of the motor frame from the conventional round to a nearly square one, a larger ratio of armature stack length to diameter, better cooling, and insulation of a higher temperature class. In addition, it is necessary to laminate the housing partially or completely and to include a compensating winding. The basic motor configuration is 1 M 1001, according to Council of Mutual Economic Assistance (CEMA) Standard 246-78, with at least IP 23S protection and 1C 06 or 1C 05 cooling (shaft height from 112 mm up) and 1C 01 cooling (Shaft height or up to 250 mm). The series will be designed for a reference speed of 1500 rpm with not more than 15% armature current fluctuation, with speeds of 300-3000 rpm depending on voltage and motor size and torque regulation 1:200 (externally cooled motors) or 1;5, 1:10, 1:30 (self-cooled motors). Prototype motors with 132 mm and 355 mm shaft heights have already passed all tests.

  15. Electrical Motor Current Signal Analysis using a Dynamic Time Warping Method for Fault Diagnosis

    International Nuclear Information System (INIS)

    This paper presents the analysis of phase current signals to identify and quantify common faults from an electrical motor based on dynamic time warping (DTW) algorithm. In condition monitoring, measurements are often taken when the motor undertakes varying loads and speeds. The signals acquired in these conditions show similar profiles but have phase shifts, which do not line up in the time-axis for adequate comparison to discriminate the small changes in machine health conditions. In this study, DTW algorithms are exploited to align the signals to an ideal current signal constructed based on average operating conditions. In this way, comparisons between the signals can be made directly in the time domain to obtain residual signals. These residual signals are then based on to extract features for detecting and diagnosing the faults of the motor and components operating under different loads and speeds. This study provides a novel approach to the analysis of electrical current signal for diagnosis of motor faults. Experimental data sets of electrical motor current signals have been studied using DTW algorithms. Results show that DTW based residual signals highlights more the modulations due to the compressor process. And hence can obtain better fault detection and diagnosis results.

  16. A current monitoring system for diagnosing electrical failures in induction motors

    Science.gov (United States)

    Acosta, G. G.; Verucchi, C. J.; Gelso, E. R.

    2006-05-01

    Induction motors are critical components in industrial processes. A motor failure may yield an unexpected interruption at the industrial plant, with consequences in costs, product quality, and safety. Many of these faulty situations in three phase induction motors have an electrical reason. Among different detection approaches proposed in the literature, those based on stator current monitoring are advantageous due to its non-invasive properties. One of these techniques resorts to spectrum analysis of machine line current. Another non-invasive technique is the Extended Park's Vector Approach, which allows the detection of inter-turn short circuits in the stator winding. This article presents the development of an on-line current monitoring system that uses both techniques for fault detection and diagnosis in the stator and in the rotor. Based on experimental observations and on the knowledge of the electrical machine, a knowledge-based system was constructed in order to carry out the diagnosis task from these estimated data.

  17. Current-Driven Supramolecular Motor with In Situ Surface Chiral Directionality Switching.

    Science.gov (United States)

    Mishra, Puneet; Hill, Jonathan P; Vijayaraghavan, Saranyan; Van Rossom, Wim; Yoshizawa, Shunsuke; Grisolia, Maricarmen; Echeverria, Jorge; Ono, Teruo; Ariga, Katsuhiko; Nakayama, Tomonobu; Joachim, Christian; Uchihashi, Takashi

    2015-07-01

    Surface-supported molecular motors are nanomechanical devices of particular interest in terms of future nanoscale applications. However, the molecular motors realized so far consist of covalently bonded groups that cannot be reconfigured without undergoing a chemical reaction. Here we demonstrate that a platinum-porphyrin-based supramolecularly assembled dimer supported on a Au(111) surface can be rotated with high directionality using the tunneling current of a scanning tunneling microscope (STM). Rotational direction of this molecular motor is determined solely by the surface chirality of the dimer, and most importantly, the chirality can be inverted in situ through a process involving an intradimer rearrangement. Our result opens the way for the construction of complex molecular machines on a surface to mimic at a smaller scale versatile biological supramolecular motors. PMID:26098301

  18. Ground Return Current Behaviour in High Voltage Alternating Current Insulated Cables

    Directory of Open Access Journals (Sweden)

    Roberto Benato

    2014-12-01

    Full Text Available The knowledge of ground return current in fault occurrence plays a key role in the dimensioning of the earthing grid of substations and of cable sealing end compounds, in the computation of rise of earth potential at substation sites and in electromagnetic interference (EMI on neighbouring parallel metallic conductors (pipes, handrails, etc.. Moreover, the ground return current evaluation is also important in steady-state regime since this stray current can be responsible for EMI and also for alternating current (AC corrosion. In fault situations and under some assumptions, the ground return current value at a substation site can be computed by means of k-factors. The paper shows that these simplified and approximated approaches have a lot of limitations and only multiconductor analysis can show the ground return current behaviour along the cable (not only the two end values both in steady-state regime and in short circuit occurrence (e.g., phase-to-ground and phase-to-phase-to-ground. Multiconductor cell analysis (MCA considers the cable system in its real asymmetry without simplified and approximated hypotheses. The sensitivity of ground return current on circuit parameters (cross-bonding box resistances, substation earthing resistances, soil resistivity is presented in the paper.

  19. Smart Technique for Induction Motors Diagnosis by Monitoring the Power Factor Using Only the Measured Current

    International Nuclear Information System (INIS)

    This paper is concerned with accurate, early and reliable induction motor IM fault detection and diagnosis using an enhanced power parameter measurement technique. IM protection devices typically monitor the motor current and/or voltage to provide the motor protection from e.g. current overload, over/under voltage, etc. One of the interesting parameters to monitor is the operating power factor (PF) of the IM which provides better under-load protection compared to the motor current based approaches. The PF of the motor is determined by the level of the current and voltage that are drawn, and offers non-intrusive monitoring. Traditionally, PF estimation would require both voltage and the current measurements to apply the displacement method. This paper will use a method of determining the operating PF of the IM using only the measured current and the manufacturer data that are typically available from the nameplate and/or datasheet for IM monitoring. The novelty of this work lies in detecting very low phase imbalance related faults and misalignment. Much of the previous work has dealt with detecting phase imbalance faults at higher degrees of severity, i.e. voltage drops of 10% or more. The technique was tested by empirical measurements on test rig comprised a 1.1 kW variable speed three phase induction motor with varying output load (No load, 25%, 50%, 75% and 100% load). One common faults was introduced; imbalance in one phase as the electrical fault The experimental results demonstrate that the PF can be successfully applied for IM fault diagnosis and the present study shows that severity fault detection using PF is promising. The proposed method offers a potentially reliable, non-intrusive, and inexpensive CM tool which can be implemented with real-time monitoring systems

  20. Alternating-current conductivity and dielectric relaxation of bulk iodoargentate

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hai-Bao, E-mail: duanhaibao4660@163.com; Yu, Shan-Shan; Zhou, Hong

    2015-05-15

    Graphical abstract: The electric modulus shows single dielectric relaxation process in the measured frequency range. - Highlights: • The conduction mechanism is described by quantum mechanical tunneling model. • The applications of dielectric modulus give a simple method for evaluating the activation energy of the dielectric relaxation. • The [Ag{sub 2}I{sub 4}]{sup 2−}1-D chain and [Cu(en){sub 2}]{sup 2+} cation column form the layered stacks by hydrogen bond interactions. - Abstract: An inorganic-organic hybrid compound Cu(en){sub 2}Ag{sub 2}I{sub 4} (en = ethylenediamine) (1) was synthesized and single crystal structurally characterized. Along the [001] direction, the inorganic parts form an infinite 1-D chain and [Cu(en){sub 2}]{sup 2+} cations are separated by inorganic chain. The electrical conductivity and dielectric properties of 1 have been investigated over wide ranges of frequency. The alternating-current conductivities have been fitted to the Almond–West type power law expression with use of a single value of S. It is found that S values for 1 are nearly temperature-independent, which indicates that the conduction mechanism could be quantum mechanical tunneling (QMT) model. The dielectric loss and electric modulus show single dielectric relaxation process. The activation energy obtained from temperature-dependent electric modulus compare with the calculated from the dc conductivity plots.

  1. Inflammatory bowel diseases: an update of current treatment alternatives.

    Directory of Open Access Journals (Sweden)

    Lucrecia Suárez

    2009-11-01

    Full Text Available Inflammatory bowel diseases (IBD are characterized for having an unpredictable clinical course with periods of inactivity alternating with relapses, a very variable response to treatment and the constant threat of diverse complications. Management of IBD in children may be of particular complexity, added to the fact that published clinical trials are limited, and scientific evidence seems contradictory, explain in part why to current date there is no international consensus regarding treatment in this age group. A suitable therapy should aim at inducing and maintaining remission for as long as possible, encourage adequate growth and preventing potential complications from appearing. In more recent years, development of new therapeutic agents has allowed a more integrative approach which takes in consideration other aspects of the disease such as nutritional status, psychological welfare and general quality of life. One must also keep in mind that none of these therapeutic resources is exempt of side effects on short and long term basis, consequently, it is imperative to be thoughtful of individual features in order to make accurate clinical decisions and offer a tailored management plan which should be able to modify the disease evolution.

  2. Transcranial direct current stimulation over the supplementary motor area modulates the preparatory activation level in the human motor system

    Science.gov (United States)

    Carlsen, Anthony N.; Eagles, Jeremy S.; MacKinnon, Colum D.

    2016-01-01

    Transcranial direct current stimulation (tDCS) is a non-invasive stimulation method that can induce transient polarity-specific neuroplastic changes in cortical excitability lasting up to 1 h post-stimulation. While excitability changes with stimulation over the primary motor cortex have been well documented, the functional effects of stimulation over premotor regions are less well understood. In the present experiment, we tested how cathodal and anodal tDCS applied over the region of the supplementary motor area (SMA) affected preparation and initiation of a voluntary movement. Participants performed a simple reaction time (RT) task requiring a targeted wrist-extension in response to a go-signal. In 20% of RT trials a startling acoustic stimulus (SAS) was presented 500 ms prior to the “go” signal in order to probe the state of motor preparation. Following the application of cathodal, anodal, or sham tDCS (separate days) over SMA for 10 min, participants performed blocks of RT trials at 10 min intervals. While sham stimulation did not affect RT or incidence of early release by the SAS, cathodal tDCS led to a significant slowing of RT that peaked 10 min after the end of stimulation and was associated with a marked decrease in the incidence of movement release by the SAS. In contrast, anodal tDCS resulted in faster RTs, but the incidence of release was unchanged. These results are consistent with the SMA playing a role in the pre-planning of movements and that modulating its activity with tDCS can lead to polarity-specific changes in motor behavior. PMID:25446764

  3. Analysis of Current Harmonics in 3kV DC Catenary Caused by Specific Current Harmonics of an Asynchronous Motor

    Science.gov (United States)

    Lewandowski, Mirosław

    2010-01-01

    The mathematical model of vehicle supply system as well as the mathematical model of main circuit of locomotive with asynchronous motors have been described in this article. The necessity of analysis of disturbances caused by distorted current run of drive motors emerged together with the introduction of high power vehicles with power electronic converters. Analysis of the compatibility of traction high current circuits with circuits of the signal and traffic control systems requires the knowledge of current spectrum in a catenary, which has been taken by a vehicle. The author has described the algebraic method of calculating of the spectrum amplitudes in a catenary. It does not require laborious and time-consuming simulations of a system, which considerably decreases preliminary costs of designation and dimensioning of a vehicle drive system.

  4. 3-D analysis of eddy current in permanent magnet of interior permanent magnet motors

    International Nuclear Information System (INIS)

    Interior permanent magnet motors are widely used in various fields. However, in high-speed operations, it is important to decrease the eddy current loss in the permanent magnet. In order to decrease the eddy current loss, we propose to divide the permanent magnet. In this paper, we clarified the effect of division of permanent magnet on the eddy current loss using the 3-D finite element method. (Author)

  5. Electric Circuit Model Suitable for Common Mode Current Paths Distributing in the Motor Drive System

    Science.gov (United States)

    Mutoh, Nobuyoshi; Ogata, Mitsukatsu; Harashima, Fumio

    Experimental date are used to analyze conducted EMI noises which are produced in a motor drive system with power converters comprised of a converter and an inverter. The processes are investigated in which common mode noises (voltages and currents) are strongly influenced by voltage fluctuations occurring due to switching operations. It is found that the common mode currents are resonance currents which appear in series resonance circuits distributed in the motor drive system. The circuits have various kinds of resonance frequencies related to voltage fluctuations produced by switching operations and micro-surge voltages generated at the terminal of machines such as an ac rector or a motor. Thus, parameters of the distributed series resonance circuits are estimated using the transient waveforms obtained by separating the common mode current into waves analyzed by the FFT method. It is proved through simulations and experiments that the proposed circuit models closely represent actual electric circuits for common mode current paths distributed in the motor drive system.

  6. Bearing fault detection using motor current signal analysis based on wavelet packet decomposition and Hilbert envelope

    Directory of Open Access Journals (Sweden)

    Imaouchen Yacine

    2015-01-01

    Full Text Available To detect rolling element bearing defects, many researches have been focused on Motor Current Signal Analysis (MCSA using spectral analysis and wavelet transform. This paper presents a new approach for rolling element bearings diagnosis without slip estimation, based on the wavelet packet decomposition (WPD and the Hilbert transform. Specifically, the Hilbert transform first extracts the envelope of the motor current signal, which contains bearings fault-related frequency information. Subsequently, the envelope signal is adaptively decomposed into a number of frequency bands by the WPD algorithm. Two criteria based on the energy and correlation analyses have been investigated to automate the frequency band selection. Experimental studies have confirmed that the proposed approach is effective in diagnosing rolling element bearing faults for improved induction motor condition monitoring and damage assessment.

  7. Detection of outer raceway bearing defects in small induction motors using stator current analysis

    Indian Academy of Sciences (India)

    İzzet Y Önel; K Burak Dalci; İbrahim Senol

    2005-12-01

    We investigate the application of induction motor stator current spectral analysis (MCSA) for detection of rolling element bearing damage from the outer raceway. In this work, MCSA and vibration analysis are applied to induction motor to detect outer raceway defects in faulty bearings. Data acquisition, recording,and fast fourier transform (FFT) algorithms are done by using the LabVIEW programming language. Experimental results verify the relationship between vibration analysis and MCSA, and identify the presence of outer raceway bearing defects in induction machines. This work also indicates that detecting fault frequencies by motor currents is more difficult than detecting them by vibration analysis. The use of intensive resolution FFT is recommended in MCSA for detecting faults easily. Reinstalling a faulty bearing can alter the characteristic frequencies and it is difficult to compare results from different bearings or even from the same bearing in different installations.

  8. Simplified Modeling, Analysis and Simulation of Permanent Magnet Brushless Direct Current Motors for Sensorless Operation

    Directory of Open Access Journals (Sweden)

    E. Kaliappan

    2012-01-01

    Full Text Available Problem statement: In this study, a simplified modeling and experimental analysis of Permanent Magnet Brushless DC (PMBLDC motors for Sensorless operation using MATLAB/SIMULINK. This model provides a mechanism for monitoring and controlling the voltage, current, speed and torque response. Approach: BLDC motor is modeled as sub-blocks. The inverter and switching function are implemented as S-function builder block. The Sensorless scheme employs direct back emf based zero crossing detection technique. Results: The proposed model with Sensorless control technique with back emf zero crossing detection is tested in the BLDC Motor and the performance was evaluated. The simulated and experimental results show that the proposed modeling works quite well during starting and running conditions. Conclusion/Recommendation: The developed model consists of several independent sub-blocks, that can be used in the modeling of Permanent Magnet Sinusoidal Motor and induction motor. Hence the developed simulation model is a design tool to study the dynamic behavior of Sensorless Controlled Brushless DC Motor.

  9. Electrical motor current signal analysis using a modified bispectrum for fault diagnosis of downstream mechanical equipment

    Science.gov (United States)

    Gu, F.; Shao, Y.; Hu, N.; Naid, A.; Ball, A. D.

    2011-01-01

    This paper presents the use of the induction motor current to identify and quantify common faults within a two-stage reciprocating compressor based on bispectrum analysis. The theoretical basis is developed to understand the nonlinear characteristics of current signals when the motor undertakes a varying load under different faulty conditions. Although conventional bispectrum representation of current signal allows the inclusion of phase information and the elimination of Gaussian noise, it produces unstable results due to random phase variation of the sideband components in the current signal. A modified bispectrum based on the amplitude modulation feature of the current signal is then adopted to combine both lower sidebands and higher sidebands simultaneously and hence characterise the current signal more accurately. Based on this new bispectrum analysis a more effective diagnostic feature, namely normalised bispectral peak, is developed for fault classification. In association with the kurtosis value of the raw current signal, the bispectrum feature gives rise to reliable fault classification results. In particular, the low feature values can differentiate the belt looseness from the other fault cases and different degrees of discharge valve leakage and inter-cooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to the analysis of stator current for the diagnosis of motor drive faults from downstream driving equipment.

  10. Transcranial direct current stimulation of the primary motor cortex improves word-retrieval in older adults.

    Directory of Open Access Journals (Sweden)

    Marcus eMeinzer

    2014-09-01

    Full Text Available Language facilitation by transcranial direct current stimulation (tDCS in healthy individuals has generated hope that tDCS may also allow improving language impairment after stroke (aphasia. However, current stimulation protocols have yielded variable results and may require identification of residual language cortex using functional magnetic resonance imaging (fMRI, which complicates incorporation into clinical practice. Based on previous behavioral studies that demonstrated improved language processing by motor system pre-activation, the present study assessed whether tDCS administered to the primary motor cortex (M1 can enhance language functions.This proof-of-concept study employed a sham-tDCS controlled, cross-over, within-subject design and assessed the impact of unilateral excitatory (anodal and bihemispheric (dual tDCS in eighteen healthy older adults during semantic word-retrieval and motor speech tasks. Simultaneous fMRI scrutinized the neural mechanisms underlying tDCS effects.Both active tDCS conditions significantly improved word-retrieval compared to sham-tDCS. The direct comparison of activity elicited by word-retrieval vs. motor-speech trials revealed bilateral frontal activity increases during both anodal- and dual-tDCS compared to sham-tDCS. This effect was driven by more pronounced deactivation of frontal regions during the motor-speech task, while activity during word-retrieval trials was unaffected by the stimulation. No effects were found in M1 and secondary motor regions.Our results show that tDCS administered to M1 can improve word-retrieval in healthy individuals, thereby providing a rationale to explore whether M1-tDCS may offer a novel approach to improve language functions in aphasia. fMRI revealed neural facilitation specifically during motor speech trials, which may have reduced switching costs between the overlapping neural systems for lexical retrieval and speech processing, thereby resulting in improved

  11. Permanent Magnet Eddy Current Loss Analysis of a Novel Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Zhang, Yuqiu; Lu, Kaiyuan; Ye, Yunyue

    2012-01-01

    In this paper, a new motor integrated permanent magnet gear (MIPMG) is discussed. The focus is on eddy current loss analysis associated to permanent magnets (PMs). A convenient model of MIPMG is provided based on 2-D field-motion coupled time-stepping finite element method for transient eddy...... current analysis. The model takes the eddy current effect of PMs into account in determination of the magnetic field in the air-gap and in the magnet regions. The eddy current losses generated in the magnets are properly interpreted. Design improvements for reducing the eddy current losses are suggested...

  12. Phase-compensation-based dynamic time warping for fault diagnosis using the motor current signal

    Science.gov (United States)

    Zhen, D.; Zhao, H. L.; Gu, F.; Ball, A. D.

    2012-05-01

    Dynamic time warping (DTW) is a time-domain-based method and widely used in various similar recognition and data mining applications. This paper presents a phase-compensation-based DTW to process the motor current signals for detecting and quantifying various faults in a two-stage reciprocating compressor under different operating conditions. DTW is an effective method to align two signals for dissimilarity analysis. However, it has drawbacks such as singularities and high computational demands that limit its application in processing motor current signals for obtaining modulation characteristics accurately in diagnosing compressor faults. Therefore, a phase compensation approach is developed to reduce the singularity effect and a sliding window is designed to improve computing efficiency. Based on the proposed method, the motor current signals measured from the compressor induced with different common faults are analysed for fault diagnosis. Results show that residual signal analysis using the phase-compensation-based DTW allows the fault-related sideband features to be resolved more accurately for obtaining reliable fault detection and diagnosis. It provides an effective and easy approach to the analysis of motor current signals for better diagnosis in the time domain in comparison with conventional Fourier-transform-based methods.

  13. Sensorless Position Measurement Based on PWM Eddy Current Variation for Switched Reluctance Motor

    OpenAIRE

    Laurent, Philippe; Multon, Bernard; Hoang, Emmanuel; Gabsi, Mohamed

    1995-01-01

    This paper proposes a new method for indirect sensing of the rotor position in a switched reluctance motor. The method operates with the rotor eddy current losses produced by the PWM converter switching, regardless of magnetic saturation. Experimental results concerning sensivity and performances are schown in a 6/4 30W 3000rpm SRM.

  14. Phase-compensation-based dynamic time warping for fault diagnosis using the motor current signal

    International Nuclear Information System (INIS)

    Dynamic time warping (DTW) is a time-domain-based method and widely used in various similar recognition and data mining applications. This paper presents a phase-compensation-based DTW to process the motor current signals for detecting and quantifying various faults in a two-stage reciprocating compressor under different operating conditions. DTW is an effective method to align two signals for dissimilarity analysis. However, it has drawbacks such as singularities and high computational demands that limit its application in processing motor current signals for obtaining modulation characteristics accurately in diagnosing compressor faults. Therefore, a phase compensation approach is developed to reduce the singularity effect and a sliding window is designed to improve computing efficiency. Based on the proposed method, the motor current signals measured from the compressor induced with different common faults are analysed for fault diagnosis. Results show that residual signal analysis using the phase-compensation-based DTW allows the fault-related sideband features to be resolved more accurately for obtaining reliable fault detection and diagnosis. It provides an effective and easy approach to the analysis of motor current signals for better diagnosis in the time domain in comparison with conventional Fourier-transform-based methods. (paper)

  15. Experimental Investigations on PV Powered SVM-DTC Induction Motor without AC Phase Current Sensors

    Directory of Open Access Journals (Sweden)

    T. Muthamizhan

    2014-05-01

    Full Text Available The paper presents a low-cost, phase-current reconstruction algorithm for space vector modulated direct torque controlled induction motor using the information obtained from only one shunt resistor which is in series with low side switches in a conventional three-phase inverter. The aim is to develop a low-cost high - performance induction motor drive. It uses the dc-link voltage and dc current to reconstruct the stator currents needed to estimate the motor flux and the electromagnetic torque. Photovoltaic arrays convert solar power to dc electric power; uses chopper and dc-ac inverter to fed three phase Induction Motor. The chopper used here is current fed full bridge boost dc-dc converter, which is preferred and extensively used in high voltage applications and advantageous over voltage fed converters. The inverter switches are controlled by PWM techniques obtained from SVM-DTC of IM. The experimental investigations are given to prove the ability of the proposed scheme of reproducing the performances of a SVM- DTC IM drive.

  16. Optimum torque control of a two-phase asymmetric induction motor fed with controlled currents

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, M.A.A.; Andrade, D.A.; Martins Neto, L.; Bissochi, C.A. Jr [Univ. of Uberlandia, Dept. of Electrical Engineering (Brazil)

    2000-08-01

    This work presents an analysis of the behaviour of a too phase asymmetrical induction motor fed with controlled currents, with a view to torque control. The mathematical model of the asymmetric two-phase motor in the reference frame ab/AB with no transformation of co-ordinates presented. Optimum torque control is obtained with vector control technique, and the conditions to obtain vector control are outlined. Digital simulation is performed under different conditions as follows: balanced and unbalanced voltage supply, amplitude control of the stator mmf and vector control. The possibility for high dynamic performance using the asymmetrical induction machine is shown to be easily obtainable. (orig.)

  17. Rotor Time Constant Compensation for Vector-Controlled Induction Motor with DC Current Injection Method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Joo; Choi, Jong woo; Kim, Heung Geung [Kyungpook National University, Taegu(Korea); Lee, Deulk Kee [Kumi College, Kumi(Korea); Jung, Jong Jin [Sungduk College, Yongcheon(Korea); Nho, Eui Cheol [Pukyong National University, Pusan(Korea); Chun, Tae Won [University of UIsan, UIsan(Korea)

    2002-02-01

    To obtain a high performance in a vector controlled induction motor, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly caries due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. this paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations and experimentals. (author). 12 refs., 14 figs., 1 tab.

  18. Parameter Estimation of Inverter and Motor Model at Standstill using Measured Currents Only

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Knudsen, Morten; Tønnes, M.

    1996-01-01

    the system is the reference values for the stator voltages given as duty cycles for the Pulse With Modulated power device. The system output is the measured stator currents. Three experiments are describedgiving respectively 1) the stator resistance and inverter parameters, 2) the stator transient......Methods for estimation of the parameters in the electrical equivalent diagram for the induction motor, based on special designed experiments, are given. In all experriments two of the three phases are given the same potential, i.e., no net torque is generatedand the motor is at standstill. Input to...

  19. Current Status of Helium-3 Alternative Technologies for Nuclear Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kouzes, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McElroy, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peerani, P. [European Commission, Ispra (Italy). Joint Research Centre; Aspinall, M. [Hybrid Instruments Ltd., Birmingham (United Kingdom); Baird, K. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Bakel, A. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Borella, M. [SCK.CEN, Mol (Belgium); Bourne, M. [Univ. of Michigan, Ann Arbor, MI (United States); Bourva, L. [Canberra Ltd., Oxford (United Kingdom); Cave, F. [Hybrid Instruments Ltd., Birmingham (United Kingdom); Chandra, R. [Arktis Radiation Detectors Ltd., Zurich (Sweden); Chernikova, D. [Chalmers Univ. of Technology (Sweden); Croft, S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dermody, G. [Symetrica Inc., Maynard, MA (United States); Dougan, A. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Ely, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fanchini, E. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Finocchiaro, P. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Gavron, Victor [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kureta, M. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Ianakiev, Kiril Dimitrov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ishiyama, K. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Lee, T. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Martin, Ch. [Symetrica Inc., Maynard, MA (United States); McKinny, K. [GE Reuter-Stokes, Twinsburg, OH (United States); Menlove, Howard Olsen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Orton, Ch. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Pappalardo, A. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Pedersen, B. [European Commission, Ispra (Italy). Joint Research Centre; Peranteau, D. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Plenteda, R. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Pozzi, S. [Univ. of Michigan, Ann Arbor, MI (United States); Schear, M. [Symetrica Inc., Maynard, MA (United States); Seya, M. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Siciliano, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stave, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sun, L. [Proportional Technologies Inc., Houston, TX (United States); Swinhoe, Martyn Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tagziria, H. [European Commission, Ispra (Italy). Joint Research Centre; Vaccaro, S. [DG Energy (Luxembourg); Takamine, J. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Weber, A. -L. [Inst. for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses (France); Yamaguchi, T. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Zhu, H. [National Nuclear Security Administration (NNSA), Washington, DC (United States)

    2015-12-01

    International safeguards inspectorates (e.g., International Atomic Energy Agency {IAEA}, or Euratom) rely heavily on neutron assay techniques, and in particular, on coincidence counters for the verification of declared nuclear materials under safeguards and for monitoring purposes. While 3He was readily available, the reliability, safety, ease of use, gamma-ray insensitivity, and high intrinsic thermal neutron detection efficiency of 3He-based detectors obviated the need for alternative detector technologies. However, the recent decline of the 3He gas supply has triggered international efforts to develop and field neutron detectors that make use of alternative materials. In response to this global effort, the U.S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) and Euratom launched a joint effort aimed at bringing together international experts, technology users and developers in the field of nuclear safeguards to discuss and evaluate the proposed 3He alternative materials and technologies. The effort involved a series of two workshops focused on detailed overviews and viability assessments of various 3He alternative technologies for use in nuclear safeguards applications. The key objective was to provide a platform for collaborative discussions and technical presentations organized in a compact, workshop-like format to stimulate interactions among the participants. The meetings culminated in a benchmark exercise providing a unique opportunity for the first inter-comparison of several available alternative technologies. This report provides an overview of the alternative technology efforts presented during the two workshops along with a summary of the benchmarking activities and results. The workshop recommendations and key consensus observations are discussed in the report, and used to outline a proposed path forward and future needs foreseeable in the area of 3He-alternative

  20. Current Status of Helium-3 Alternative Technologies for Nuclear Safeguards

    International Nuclear Information System (INIS)

    International safeguards inspectorates (e.g., International Atomic Energy Agency, or Euratom) rely heavily on neutron assay techniques, and in particular, on coincidence counters for the verification of declared nuclear materials under safeguards and for monitoring purposes. While 3He was readily available, the reliability, safety, ease of use, gamma-ray insensitivity, and high intrinsic thermal neutron detection efficiency of 3He-based detectors obviated the need for alternative detector technologies. However, the recent decline of the 3He gas supply has triggered international efforts to develop and field neutron detectors that make use of alternative materials. In response to this global effort, the U.S. Department of Energy's (DOE) National Nuclear Security Administration (NNSA) and Euratom launched a joint effort aimed at bringing together international experts, technology users and developers in the field of nuclear safeguards to discuss and evaluate the proposed 3He alternative materials and technologies. The effort involved a series of two workshops focused on detailed overviews and viability assessments of various 3He alternative technologies for use in nuclear safeguards applications. The key objective was to provide a platform for collaborative discussions and technical presentations organized in a compact, workshop-like format to stimulate interactions among the participants. The meetings culminated in a benchmark exercise providing a unique opportunity for the first inter-comparison of several available alternative technologies. This report provides an overview of the alternative technology efforts presented during the two workshops along with a summary of the benchmarking activities and results. The workshop recommendations and key consensus observations are discussed in the report, and used to outline a proposed path forward and future needs foreseeable in the area of 3He-alternative technologies.

  1. PERFORMANCE OPTIMIZATION OF LINEAR INDUCTION MOTOR BY EDDY CURRENT AND FLUX DENSITY DISTRIBUTION ANALYSIS

    Directory of Open Access Journals (Sweden)

    M. S. MANNA

    2011-12-01

    Full Text Available The development of electromagnetic devices as machines, transformers, heating devices confronts the engineers with several problems. For the design of an optimized geometry and the prediction of the operational behaviour an accurate knowledge of the dependencies of the field quantities inside the magnetic circuits is necessary. This paper provides the eddy current and core flux density distribution analysis in linear induction motor. Magnetic flux in the air gap of the Linear Induction Motor (LIM is reduced to various losses such as end effects, fringes, effect, skin effects etc. The finite element based software package COMSOL Multiphysics Inc. USA is used to get the reliable and accurate computational results for optimization the performance of Linear Induction Motor (LIM. The geometrical characteristics of LIM are varied to find the optimal point of thrust and minimum flux leakage during static and dynamic conditions.

  2. Speed Control Analysis of Brushless DC Motor Based on Maximum Amplitude DC Current Feedback

    Directory of Open Access Journals (Sweden)

    Hassan M.A.A.

    2014-07-01

    Full Text Available This paper describes an approach to develop accurate and simple current controlled modulation technique for brushless DC (BLDC motor drive. The approach is applied to control phase current based on generation of quasi-square wave current by using only one current controller for the three phases. Unlike the vector control method which is complicated to be implemented, this simple current modulation technique presents advantages such as phase currents are kept in balance and the current is controlled through only one dc signal which represent maximum amplitude value of trapezoidal current (Imax. This technique is performed with Proportional Integral (PI control algorithm and triangular carrier comparison method to generate Pulse Width Modulation (PWM signal. In addition, the PI speed controller is incorporated with the current controller to perform desirable speed operation of non-overshoot response. The performance and functionality of the BLDC motor driver are verified via simulation by using MATLAB/SIMULINK. The simulation results show the developed control system performs desirable speed operation of non-overshoot and good current waveforms.

  3. Task-specific effect of transcranial direct current stimulation on motor learning

    Directory of Open Access Journals (Sweden)

    Cinthia Maria Saucedo Marquez

    2013-07-01

    Full Text Available Transcranial direct current stimulation (tDCS is a relatively new non-invasive brain stimulation technique that modulates neural processes. When applied to the human primary motor cortex (M1, tDCS has beneficial effects on motor skill learning and consolidation in healthy controls and in patients. However, it remains unclear whether tDCS improves motor learning in a general manner or whether these effects depend on which motor task is acquired. Here we compare whether the effect of tDCS differs when the same individual acquires (1 a Sequential Finger Tapping Task (SEQTAP and (2 a Visual Isometric Pinch Force Task (FORCE. Both tasks have been shown to be sensitive to tDCS applied over M1, however, the underlying processes mediating learning and memory formation might benefit differently from anodal-tDCS. Thirty healthy subjects were randomly assigned to an anodal-tDCS group or sham-group. Using a double-blind, sham-controlled cross-over design, tDCS was applied over M1 while subjects acquired each of the motor tasks over 3 consecutive days, with the order being randomized across subjects. We found that anodal-tDCS affected each task differently: The SEQTAP task benefited from anodal-tDCS during learning, whereas the FORCE task showed improvements only at retention. These findings suggest that anodal tDCS applied over M1 appears to have a task-dependent effect on learning and memory formation.

  4. Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

    Energy Technology Data Exchange (ETDEWEB)

    Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

    1997-12-31

    Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

  5. A comparison of alternating current and direct current electrospray ionization for mass spectrometry.

    Science.gov (United States)

    Sarver, Scott A; Chetwani, Nishant; Dovichi, Norman J; Go, David B; Gartner, Carlos A

    2014-04-01

    A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS have been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were one to two orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50%, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one-half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating that improvements in spectral quality may benefit certain compounds or classes of compounds, on an individual basis. PMID:24464359

  6. Experiments with alternate currents of very high frequency

    CERN Document Server

    Tesla, Nikola

    2013-01-01

    Here is one of Nikola Tesla's most important lectures; it brightened the world and everything in it. Of all these phenomena the most important to study' are the current phenomena, on account of the already extensive and evergrowing use of currents for industrial purposes. It is now a century since the first practical source of current was produced, and, ever since, the phenomena which accompany the flow of currents have been diligently studied, and through the untiring efforts of scientific men the simple laws which govern them have been discovered.

  7. Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

    Science.gov (United States)

    Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

    2013-01-01

    Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time

  8. Fault tolerance control of phase current in permanent magnet synchronous motor control system

    Science.gov (United States)

    Chen, Kele; Chen, Ke; Chen, Xinglong; Li, Jinying

    2014-08-01

    As the Photoelectric tracking system develops from earth based platform to all kinds of moving platform such as plane based, ship based, car based, satellite based and missile based, the fault tolerance control system of phase current sensor is studied in order to detect and control of failure of phase current sensor on a moving platform. By using a DC-link current sensor and the switching state of the corresponding SVPWM inverter, the failure detection and fault control of three phase current sensor is achieved. Under such conditions as one failure, two failures and three failures, fault tolerance is able to be controlled. The reason why under the method, there exists error between fault tolerance control and actual phase current, is analyzed, and solution to weaken the error is provided. The experiment based on permanent magnet synchronous motor system is conducted, and the method is proven to be capable of detecting the failure of phase current sensor effectively and precisely, and controlling the fault tolerance simultaneously. With this method, even though all the three phase current sensors malfunction, the moving platform can still work by reconstructing the phase current of the motor.

  9. Comparison of Unmodulated Current Control Characteristics of Permanent Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Anwar Muqorobin

    2014-12-01

    Full Text Available This paper discusses comparison of unmodulated current controls in PMSM, more specifically, on-off, sliding mode, predictive and hybrid controls. The purpose of this study is to select the most appropriate control technique to be adopted. The comparison method is preceded by modeling the motor and entering the values of the motor parameters. PI control is used for speed control and zero d-axis current is employed. Furthermore, performing simulation for each type ofthe selected current controls and analyzing their responses in terms of dq and abc currents, q-axis current response with step reference, as well as THD. Simulation results show that the on-off control gives the best overall performance based on its abc-axis current ripple and THD at large load torque. The hybrid control shows the best response occurring only at the fastest transient time of q-axis current but its response exhibits bad qualities compared with other controls. The predictive control yields the best responses offering the smallest d-axis ripple current and THD at small load torque condition. The sliding mode control, however, does not exhibit any prominent performance compared to the others. Results presented in this paper further indicate that for the PMSM used in the simulation the most appropriate control is the predictive control.

  10. Desempenho de um microtrator utilizando-se motores com diferentes alternativas energéticas = Performance of a microtractor using engines with different energetic alternatives

    Directory of Open Access Journals (Sweden)

    Denílson Eduardo Rodrigues

    2006-01-01

    Full Text Available Neste trabalho avaliou-se o desempenho de um microtrator equipado com três diferentes tipos de acionamento. Um mesmo chassi de um microtrator foi instalado, alternadamente, com um motor elétrico trifásico (MCA, um motor elétrico de corrente contínua (MCC e com um motor de combustão interna (MCI. Os ensaios do microtrator com cada um dos motores permitiram a determinação da força de tração máxima, da velocidade de deslocamento, do consumo de combustível e a patinagem dos rodados. O MCC desenvolveu maior força de tração, sendo 22% superior aos demais. O consumo específico de energia para os microtratores decresceu com o aumento da patinagem. This study evaluated the performance of a microtractor implemented in three different operational types. A microtractor chassis was alternately operated with a three-phase electric engine (MCA, a direct-current electric engine (MCC and an internal combustion engine (MCI. The rehearsals of the microtractor implemented in each one of the engines allowed determinations of the maximum tractive force, the forward speed and the fuel consumption in wheel skiddings. The MCC developed greater snatch force, being 22% superior to the others. The specific consumption on energy for the microtractors decreased as the skiddings increased.

  11. Design of Current Controller for Two Quadrant DC Motor Drive by Using Model Order Reduction Technique

    CERN Document Server

    Ramesh, K; Nirmalkumar, A; Gurusamy, G

    2010-01-01

    In this paper, design of current controller for a two quadrant DC motor drive was proposed with the help of model order reduction technique. The calculation of current controller gain with some approximations in the conventional design process is replaced by proposed model order reduction method. The model order reduction technique proposed in this paper gives the better controller gain value for the DC motor drive. The proposed model order reduction method is a mixed method, where the numerator polynomial of reduced order model is obtained by using stability equation method and the denominator polynomial is obtained by using some approximation technique preceded in this paper. The designed controllers responses were simulated with the help of MATLAB to show the validity of the proposed method.

  12. Analysis of the dynamic response improvement of a turbocharged diesel engine driven alternating current generating set

    International Nuclear Information System (INIS)

    Reliability of electric supply systems is among the most required necessities of modern society. Turbocharged diesel engine driven alternating current generating sets are often used to prevent electric black outs and/or as prime electric energy suppliers. It is well known that turbocharged diesel engines suffer from an inadequate response to a sudden load increase, this being a consequence of the nature of the energy exchange between the engine and the turbocharger. The dynamic response of turbocharged diesel engines could be improved by electric assisting systems, either by direct energy supply with an integrated starter-generator-booster (ISG) mounted on the engine flywheel, or by an indirect energy supply with an electrically assisted turbocharger. An experimentally verified zero dimensional computer simulation method was used for the analysis of both types of electrical assistance. The paper offers an analysis of the interaction between a turbocharged diesel engine and different electric assisting systems, as well as the requirements for the supporting electric motors that could improve the dynamic response of a diesel engine while driving an AC generating set. When performance class compliance is a concern, it is evident that an integrated starter-generator-booster outperforms an electrically assisted turbocharger for the investigated generating set. However, the electric energy consumption and frequency recovery times are smaller when an electrically assisted turbocharger is applied

  13. Extracting DC bus current information for optimal phase correction and current ripple in sensorless brushless DC motor drive

    Institute of Scientific and Technical Information of China (English)

    Zu-sheng HO; Chii-maw UANG; Ping-chieh WANG

    2014-01-01

    Brushless DC motor (BLDCM) sensorless driving technology is becoming increasingly established. However, op-timal phase correction still relies on complex calculations or algorithms. In finding the correct commutation point, the problem of phase lag is introduced. In this paper, we extract DC bus current information for auto-calibrating the phase shift to obtain the correct commutation point and optimize the control of BLDC sensorless driving. As we capture only DC bus current information, the original shunt resistor is used in the BLDCM driver and there is no need to add further current sensor components. Software processing using only simple arithmetic operations successfully accomplishes the phase correction. Experimental results show that the proposed method can operate accurately and stably at low or high speed, with light or heavy load, and is suitable for practical applications. This approach will not increase cost but will achieve the best performance/cost ratio and meet market expectations.

  14. High-Frequency Parasitic Currents in Inverter-Fed Induction Motor Drives

    Czech Academy of Sciences Publication Activity Database

    Doležel, Ivo; Škramlík, Jiří; Valouch, Viktor

    Seoul : KIEE, 2007, s. 403-407. ISBN 978-89-86510-07-2. [International Conference on Electrical Machines and System s - ICEMS 2007. Seoul (KR), 08.10.2007-11.10.2007] R&D Projects: GA ČR GA102/06/0112 Institutional research plan: CEZ:AV0Z20570509 Keywords : numerical modeling * parasitic currents * induction motor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://www.icems2007.com/

  15. Alternatives to animal testing: current status and future perspectives

    OpenAIRE

    Liebsch, Manfred; Grune, Barbara; Seiler, Andrea; Butzke, Daniel; Oelgeschläger, Michael; Pirow, Ralph; Adler, Sarah; Riebeling, Christian; Luch, Andreas

    2011-01-01

    On the occasion of the 20th anniversary of the Center for Alternative Methods to Animal Experiments (ZEBET), an international symposium was held at the German Federal Institute for Risk Assessment (BfR) in Berlin. At the same time, this symposium was meant to celebrate the 50th anniversary of the publication of the book “The Principles of Humane Experimental Technique” by Russell and Burch in 1959 in which the 3Rs principle (that is, Replacement, Reduction, and Refinement) has been coined and...

  16. A Novel Method of Phase Current Compensation for Switched Reluctance Motor System Based on Finite Element

    Directory of Open Access Journals (Sweden)

    Haijun Zhang

    2009-10-01

    Full Text Available Torque ripple is a major problem of switched reluctance motor drive system, which causes undesirable vibration and acoustic noise. In this paper, a novel method of torque closed-loop and fuzzy compensation control for the switched reluctance motor drive system based on finite element model is described. In terms of the simulation results and the special characteristics of static torquecurrent-angle which are calculated by finite element method, the phase current can be treated just as the nonlinear function of phase torque. With the proposed control concept, a compensating signal is added to the phase current, the current shape can vary with the fuzzy control ruler to minimize the torque ripple. In the end, an example of 8/6 poles switched reluctance motor is simulated. Simulation results show that the torque ripple coefficient Ti can be reduced about fifty percent and the total torque also can be advanced, which verifies the effects of the proposed fuzzy compensation control technique.

  17. Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

    Directory of Open Access Journals (Sweden)

    Kimura Akio

    2010-06-01

    Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

  18. A novel current vector decomposition controller design for six-phase permanent magnet synchronous motor

    Institute of Scientific and Technical Information of China (English)

    袁雷; 胡冰新; 魏克银; 林莹

    2016-01-01

    The vector control algorithm based on vector space decomposition (VSD) transformation method has a more flexible control freedom, which can control the fundamental and harmonic subspace separately. To this end, a current vector decoupling control algorithm for six-phase permanent magnet synchronous motor (PMSM) is designed. Using the proposed synchronous rotating coordinate transformation matrix, the fundamental and harmonic components ind−q subspace are changed into direct current (DC) component, only using the traditional proportional integral (PI) controller can meet the non-static difference adjustment, and the controller parameter design method is given by employing internal model principle. In addition, in order to remove the 5th and 7th harmonic components of stator current, the current PI controller parallel with resonant controller is employed inx−y subspace to realize the specific harmonic component compensation. Simulation results verify the effectiveness of current decoupling vector controller.

  19. Fiske steps in Josephson junctions with alternating critical current density

    International Nuclear Information System (INIS)

    We have developed a simple model, in the framework of the Kulik theory of Fiske steps in Josephson junctions, for the electromagnetic resonances observed in the current voltage characteristics of certain high temperature superconductor grain boundary junctions. Some preliminary results are illustrated

  20. Teaching Electrical Energy, Voltage and Current: An Alternative Approach.

    Science.gov (United States)

    Licht, Pieter

    1991-01-01

    A program for teaching the concepts of electric energy, voltage, and current is proposed. The ideas and concepts are introduced in a sequence that places more emphasis on some aspects that are normally treated very briefly. A phenomenological orientation, qualitative and quantitative micro- and macroscopic treatments, and the inclusion of the…

  1. Taxation of Fringe Benefits: Alternative Approaches to Current Problems.

    Science.gov (United States)

    Cohen, Anita E.

    1979-01-01

    The current IRS tax treatment of fringe benefits is seen as inadequate, and the judicial precept confusing, because groups of employee benefits are inappropriately excluded from taxation as perquisites. A tax equalization approach is proposed. Available from Suffolk University Law Review Office, 41 Temple St., Boston, MA 02114. (MSE)

  2. Detection of mechanical failures in induction motors by current spectrum analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sokansky, K.; Novak, P.; Bilos, J.; Labaj, J. [Technical University Ostrava, Moraviasilesian Power Stations s.h.c. (Czech Republic)

    1997-12-31

    From the diagnostic point of view, an electric machine can be understood as an electromechanical system. It means that any manifestations of mechanical failures do not have to show themselves only in mechanical quantities, i.e. vibration in our case. Mechanical failures can also manifest themselves in electrical quantities, namely in electric current in our case. This statement is valid inversely too, which means that faults occurring in electric circuits can be measured through mechanical quantities. This presentation deals with measuring the current spectra of induction motors with short circuited armatures that are drives used in the industries most. (orig.) 3 refs.

  3. Analysis of energy cogeneration with alternative motors in a brewery; Analise de cogeracao de energia com motores alternativos em uma cervejaria

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Evelyn Ramiro; Almeida Silvio Carlos Anibal de [Universidade Federal do Rio de Janeiro (DEM/UFRJ), RJ (Brazil). Dept. de Engenharia Mecanica], E-mail: eng_evelyn@poli.ufrj.br

    2010-07-01

    In this study it will be presented a technical-economical simulation on a plant that needs thermal and electrical energy, simultaneously. This simulation analysis will be based on the economical and technical validity of the installation of a thermo electrical cogeneration power plant using alternative motors. The objective intends the electrical autonomy of use of thermal energy and the better plant efficiency, and lower CO{sub 2} emissions. This analysis will utilize the Cogeneration Read Reckoner, version 3.1 of the Sinclair Knight Merz.

  4. Alternating current calorimetry at very high pressure and low temperature

    CERN Document Server

    Wilhelm, H

    2002-01-01

    The specific heat of CePd sub 2 sub . sub 0 sub 2 Ge sub 1 sub . sub 9 sub 8 has been measured with an ac calorimetric technique up to 22 GPa for temperatures in the range 0.3 K <=T <=10 K. A thermocouple allowed the temperature oscillations to be read when an ac heating current was sent through the sample. The inverse of the thermovoltage V sub a sub c recorded at low temperature exhibits a pronounced anomaly as a function of pressure. It is shown that 1/V sub a sub c extrapolated to zero temperature is a measure of the Sommerfeld coefficient gamma.

  5. Josephson effects in an alternating current biased transition edge sensor

    CERN Document Server

    Gottardi, Luciano; Akamatsu, Hiroki; van der Kuur, Jan; Bruijn, Marcel P; Hartog, Roland H den; Hijmering, Richard; Khosropanah, Pourya; Lambert, Colin; van der Linden, Anton J; Ridder, Marcel L; Suzuki, Toyo; Gao, Jan R

    2016-01-01

    We report the experimental evidence of the ac Josephson effect in a transition edge sensor (TES) operating in a frequency domain multiplexer and biased by ac voltage at MHz frequencies. The effect is observed by measuring the non-linear impedance of the sensor. The TES is treated as a weakly linked superconducting system and within the resistively shunted junction model framework. We provide a full theoretical explanation of the results by finding the analytic solution of the non-inertial Langevian equation of the system and calculating the non-linear response of the detector to a large ac bias current in the presence of noise.

  6. Alternating Pulse Current in Electrocoagulation for Wastewater Treatment to Prevent the Passivation or Al Electrode

    Institute of Scientific and Technical Information of China (English)

    MAO Xuhui; HONG Song; ZHU Hua; LIN Hui; WEI Lin; GAN Fuxing

    2008-01-01

    A novel current feed style, alternating pulse current, was proposed in electrocoagulation aiming at preventing the passivation of electrode materials. The open circuit potential (OCP) measurements after anodic and cathodic potentiodynamic polarization showed that cathodic polarization could activate Al electrode. The surface of Al electrode after alternating pulse current electrocoagulation was investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), and the results indicate that passivation of Al is not observed. Furthermore, the simulated wastewater treatment tests show that alternating pulse current electrocoagulation has a visible energy saving effect and is worthy of generalization.

  7. Design and control of the phase current of a brushless dc motor to eliminate cogging torque

    Science.gov (United States)

    Jang, G. H.; Lee, C. J.

    2006-04-01

    This paper presents a design and control method of the phase current to reduce the torque ripple of a brushless dc (BLDC) motor by eliminating cogging torque. The cogging torque is the main source of torque ripple and consequently of speed error, and it is also the excitation source to generate the vibration and noise of a motor. This research proposes a modified current wave form, which is composed of main and auxiliary currents. The former is the conventional current to generate the commutating torque. The latter generates the torque with the same magnitude and opposite sign of the corresponding cogging torque at the given position in order to eliminate the cogging torque. Time-stepping finite element method simulation considering pulse-width-modulation switching method has been performed to verify the effectiveness of the proposed method, and it shows that this proposed method reduces torque ripple by 36%. A digital-signal-processor-based controller is also developed to implement the proposed method, and it shows that this proposed method reduces the speed ripple significantly.

  8. Detection of stator winding faults in induction motors using three-phase current monitoring.

    Science.gov (United States)

    Sharifi, Rasool; Ebrahimi, Mohammad

    2011-01-01

    The objective of this paper is to propose a new method for the detection of inter-turn short circuits in the stator windings of induction motors. In the previous reported methods, the supply voltage unbalance was the major difficulty, and this was solved mostly based on the sequence component impedance or current which are difficult to implement. Some other methods essentially are included in the offline methods. The proposed method is based on the motor current signature analysis and utilizes three phase current spectra to overcome the mentioned problem. Simulation results indicate that under healthy conditions, the rotor slot harmonics have the same magnitude in three phase currents, while under even 1 turn (0.3%) short circuit condition they differ from each other. Although the magnitude of these harmonics depends on the level of unbalanced voltage, they have the same magnitude in three phases in these conditions. Experiments performed under various load, fault, and supply voltage conditions validate the simulation results and demonstrate the effectiveness of the proposed technique. It is shown that the detection of resistive slight short circuits, without sensitivity to supply voltage unbalance is possible. PMID:21074767

  9. Alternating Current All-electrical Gun Control System in Tanks

    Directory of Open Access Journals (Sweden)

    Zang Kemao

    2004-07-01

    Full Text Available The ac all-electrical gun control system is composed of permanent magnetic synchronous machine-drive control systems and the ball-screw by replacing the complicated electrohydraulic systems. At the same time, the variable-structure system with sliding modes makes the gun control systems to have higher performances using the only rate flexure gyroscope. Thereby, vehicle hull gyroscope and angular gyroscope are left out.The new ac all-electrical gun control systems developed are reduced by 40 per cent in weight, decreased by 30 per cent in volume, increased by 35 per cent in efficiency, and enhanced by three times in service life as compared to the current gun control systems.

  10. Diesel-alcohol-castor oil fuel blend as an alternative fuel for compression ignition motors; Misturas diesel-alcool-oleo de ricina como um combustivel alternativo para motores de ignicao por compressao

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, Eduardo Gagliuffi; Bastos, Jose Guilherme R.R.; Barbosa, Cleiton Rubens Formiga [Rio Grande do Norte Univ., Natal, RN (Brazil). Centro de Tecnologia. Dept. de Engenharia Mecanica]. E-mail: eduardo@dem.ufrn.br

    2000-07-01

    This work evaluates some characteristics of the diesel-alcohol-castor oil ternary blends, where the castor oil is used as co-solvent viewing the using in compression ignition motors. The obtained results present the possibility of using those ternary blends as alternative fuels in compression ignition motors to be adopted in regions where the blend components are available.

  11. The current situation of diagnosis for insulation deterioration of high voltage induction motors in nuclear power plants

    International Nuclear Information System (INIS)

    In order to evaluate aging effect on motor correctly, several data of high voltage induction motors in 17 nuclear power plants of Tokyo Electric Power Co. (TEPCO) have been collected since 1984. Collected data are non-destructive insulation diagnosis test data including insulation resistance, static capacitance and the results of insulation destructive test after replacement of motors. Evaluation based on the data shows that breakdown voltage (BDV) of motor coil has relationship with the motor parameters such as current increase ratio, maximum discharge magnitude, difference of dielectric dissipation factor, etc. From this viewpoint, BDV estimation formula for 6.6 kV motors is established by using multiple linear regression analysis method, considering parameter used in D-map evaluation. However the measured parameters may vary due to the factors besides insulation deterioration, not only the estimated BDV but also visual inspection data are took into account for overall diagnosis. Further collection of data and evaluation will be done continuously in order to enhance accuracy of the insulation diagnosis. The current situation of diagnosis for insulation deterioration of 6.6 kV class induction motors in nuclear power plants is described in this technical note. Also current situation of investigation on 3.3 kV class motors is described. (author)

  12. Alternate current characteristics of SiC powders

    Science.gov (United States)

    Mârtensson, E.; Gäfvert, U.; Önneby, C.

    2001-09-01

    Silicon carbide (SiC) powder is used in nonlinear field grading materials. The composite material, consisting of an insulating polymer matrix filled with the SiC grains, is usually a percolated system with established conducting paths. In order to explain the properties, the electrical characteristic of the SiC powder itself is of interest. The ac characteristics of SiC powders have been studied by dielectric response, capacitance-voltage, and ac-pulse measurements. The frequency, electric field, and pressure dependencies have been analyzed for green and black SiC, which have different doping. The ac characteristics of green and black SiC powders are governed by both the barrier regions at the SiC-grain contacts and the surrounding matrix. The nonlinear loss is determined by the conduction current at the contacts. Depending on the doping level of the SiC grains, the capacitance may be controlled by either the nonlinear capacitance of the barrier region or the linear capacitance of the surrounding matrix. Each contact zone may be modeled by a nonlinear resistance in parallel with both a nonlinear and a linear capacitance. The components are considered to be frequency independent. However, in order to explain the macroscopic frequency and field dependencies of the SiC powders, the use of a network of unique contact zones with dissimilar properties is suggested.

  13. Emission Patterns under Alternative Congestion and Motor Vehicle Pollution Mitigation Policies in Shanghai

    Institute of Scientific and Technical Information of China (English)

    Chen Hongfeng; Li Fen; Li Xiangling

    2007-01-01

    As a megacity with thriving economy, Shanghai is experiencing rapid motorisation and confronted with traffic congestion problems despite its low car ownership. It is of value to look into the policies on emission control of motor vehicle and congestion reduction in such a city to explore how to reconcile mobility enhancement with the environment. Results of a dynamic simulation displayed time paths of emissions from motor vehicles in Shanghai over the period from 2000 to 2020. The simulation results showed that early policies on emission control of motor vehicle could bring about far-reaching effects on emission reduction, and take advantage of available low-polluting technologies and technical innovation over time. Travel demand management would play an important role in curbing congestion and reducing motor vehicle pollution by calming down car ownership rise and deterring inefficient trips as well as reducing fuel waste caused by congestion.

  14. A Sensorless Speed Control using Stator Ripple Currents for an Induction Motor Drive with Space Phasor PWM

    OpenAIRE

    Mohapatra, KK; Gopakumar, K.; Baiju, MR; Murty, BV

    2004-01-01

    In the present paper a simple sensorless speed estimation scheme is presented, where the speed information is obtained from the motor phase current ripple. The scheme measures the stator current phasor deviation direction to determine the back EMF vector position during inverter zero vector switching states. This measurement of rotor flux position is done indirectly by computing the motor back EMF position which is orthogonal to the rotor flux position. The space vector PWM voltage output in ...

  15. Control of Pseudo-Sinusoidal Switched Reluctance Motor with Zero Torque Ripple and Damped Input Current Ripple

    OpenAIRE

    Van Du, Le

    2013-01-01

    Switched reluctance motor(SRM)drives are favored in many industrial applications because of their cost advantage and ruggedness. However, the torque ripple and bus current ripple of SRM restrict its application range  compared with traditional AC and DC motors due to the doubly salient pole structure and the highly non-linear coupling between torque, rotor position and phase current. As a result of the torque ripple on the shaft, unwilling large acoustic noises are generated. The large curren...

  16. Laser agitates probability flow in atoms to form alternating current and its peak-dip phenomenon

    CERN Document Server

    Cui, Huai-Yang

    2016-01-01

    By using trajectory-based approaches to quantum transition, it is found that laser can agitate the probability flow in atoms to form alternating current with the frequency of the laser. The detailed physical process of quantum transition is investigated, during which the alternating current in atomic probability flow becomes a key role connecting the external electromagnetic wave with the evolution of the quantum states in atoms. Computer was employed to simulate the physical process. The atomic alternating current may have the peak-dip phenomenon.

  17. Improvement of immunoassay detection system by using alternating current magnetic susceptibility

    Science.gov (United States)

    Kawabata, R.; Mizoguchi, T.; Kandori, A.

    2016-03-01

    A major goal with this research was to develop a low-cost and highly sensitive immunoassay detection system by using alternating current (AC) magnetic susceptibility. We fabricated an improved prototype of our previously developed immunoassay detection system and evaluated its performance. The prototype continuously moved sample containers by using a magnetically shielded brushless motor, which passes between two anisotropic magneto resistance (AMR) sensors. These sensors detected the magnetic signal in the direction where each sample container passed them. We used the differential signal obtained from each AMR sensor's output to improve the signal-to-noise ratio (SNR) of the magnetic signal measurement. Biotin-conjugated polymer beads with avidin-coated magnetic particles were prepared to examine the calibration curve, which represents the relation between AC magnetic susceptibility change and polymer-bead concentration. For the calibration curve measurement, we, respectively, measured the magnetic signal caused by the magnetic particles by using each AMR sensor installed near the upper or lower part in the lateral position of the passing sample containers. As a result, the SNR of the prototype was 4.5 times better than that of our previous system. Moreover, the data obtained from each AMR sensor installed near the upper part in the lateral position of the passing sample containers exhibited an accurate calibration curve that represented good correlation between AC magnetic susceptibility change and polymer-bead concentration. The conclusion drawn from these findings is that our improved immunoassay detection system will enable a low-cost and highly sensitive immunoassay.

  18. Harsh-environment motor renovation - the only alternative in an emergency

    International Nuclear Information System (INIS)

    It is difficult for utilities to obtain identical replacements for safety-related motors in an emergency because of the limited number of renovation facilities and the utilities' understanding of the renovation process. This paper addresses the renovation of motors installed in harsh environments. It also applies to mild-environment safety-related materials, wherein improperly related electrical materials could affect seismic qualification and catastrophic failures while operating at the motor's temperature extreme. The purpose of this paper is to provide utilities with insight into today's renovation process and its complexity when dealing with issues such as regulatory guides 10CFR50.49, 10CFR50 Appendix B, and 10CFR21

  19. Performance evaluation of directly photovoltaic powered DC PM (direct current permanent magnet) motor – propeller thrust system

    International Nuclear Information System (INIS)

    Photovoltaic (PV) powered directly coupled electro-mechanical system has wide applications (e.g. PV powered cooling fans in green houses, PV water pumping system, solar vehicles). The objective of this work is to analyse the operation of directly PV powered DC PM (direct current permanent magnet) motor – propeller system for selection of motor parameters. The performance of such system mainly depends on the incident solar radiation, operating cell temperature, DC motor and propeller load parameters. It is observed that the operating points of the PV DC PM motor – propeller system matches very closely with the maximum power points (MPPs) of the PV array, if the DC PM motor – propeller parameters have been properly selected. It is found that for a specific application of such type of system, matching of torque–speed operating points with respect to the maximum power points of PV array are very important. It is ascertained through results that the DC PM motor's armature resistance, magnetic field constant, starting current to overcome the starting torque and torque coefficient are the main parameters. In designing a PV powered DC PM motor for a specific application, selection of these parameters are important for maximum utilization of the PV array output. The results of this system are useful for designing of directly PV powered DC PM motor's for aerodynamic applications. - Highlights: • We analyse the performance of directly PV powered DC PM motor – propeller system. • We examine PV electro-mechanical system for selection of DC motor parameters. • Matching of torque–speed curve to maximum power points of PV array is important

  20. Alternative Stimulation Intensities for Mapping Cortical Motor Area with Navigated TMS.

    Science.gov (United States)

    Kallioniemi, Elisa; Julkunen, Petro

    2016-05-01

    Navigated transcranial magnetic stimulation (nTMS) is becoming a popular tool in pre-operative mapping of functional motor areas. The stimulation intensities used in the mapping are commonly suprathreshold intensities with respect to the patient's resting motor threshold (rMT). There is no consensus on which suprathreshold intensity should be used nor on the optimal criteria for selecting the appropriate stimulation intensity (SI). In this study, the left motor cortices of 12 right-handed volunteers (8 males, age 24-61 years) were mapped using motor evoked potentials with an SI of 110 and 120 % of rMT and with an upper threshold (UT) estimated by the Mills-Nithi algorithm. The UT was significantly lower than 120 % of rMT (p < 0.001), while no significant difference was observed between UT and 110 % of rMT (p = 0.112). The representation sizes followed a similar trend, i.e. areas computed based on UT (5.9 cm(2)) and 110 % of rMT (5.0 cm(2)) being smaller than that of 120 % of rMT (8.8 cm(2)) (p ≤ 0.001). There was no difference in representation sizes between 110 % of rMT and UT. The variance in representation size was found to be significantly lower with UT compared to 120 % of rMT (p = 0.048, uncorrected), while there was no difference between 110 % of rMT and UT or 120 % of rMT. Indications of lowest inter-individual variation in representation size were observed with UT; this is possibly due to the fact that it takes into account the individual input-output characteristics of the motor cortex. Therefore, the UT seems to be a good option for SI in motor mapping applications to outline functional motor areas with nTMS and it could potentially reduce the inter-individual variation caused by the selection of SI in motor mapping in pre-surgical applications and radiosurgery planning. PMID:26830768

  1. Choice Of Input Data Type Of Artificial Neural Network To Detect Faults In Alternative Current Systems

    Directory of Open Access Journals (Sweden)

    T. Benslimane

    2006-01-01

    Full Text Available This paper present a study on different input data types of ANN used to detect faults such as over-voltage in AC systems (AC network , induction motor. The input data of ANN are AC voltage and current. In no fault condition, voltage and current are sinusoidal. The input data of the ANN may be the instantaneous values of voltage and current, their RMS values or their average values after been rectified. In this paper we presented different characteristics of each one of these data. A digital software C++ simulation program was developed and simulation results were presented.

  2. Modulation of Training by Single-Session Transcranial Direct Current Stimulation to the Intact Motor Cortex Enhances Motor Skill Acquisition of the Paretic Hand

    Science.gov (United States)

    Zimerman, Máximo; Heise, Kirstin F.; Hoppe, Julia; Cohen, Leonardo G.; Gerloff, Christian; Hummel, Friedhelm C.

    2016-01-01

    Background and Purpose Mechanisms of skill learning are paramount components for stroke recovery. Recent noninvasive brain stimulation studies demonstrated that decreasing activity in the contralesional motor cortex might be beneficial, providing transient functional improvements after stroke. The more crucial question, however, is whether this intervention can also enhance the acquisition of complex motor tasks, yielding longer-lasting functional improvements. In the present study, we tested the capacity of cathodal transcranial direct current stimulation (tDCS) applied over the contralesional motor cortex during training to enhance the acquisition and retention of complex sequential finger movements of the paretic hand. Method Twelve well-recovered chronic patients with subcortical stroke attended 2 training sessions during which either cathodal tDCS or a sham intervention were applied to the contralesional motor cortex in a double-blind, crossover design. Two different motor sequences, matched for their degree of complexity, were tested in a counterbalanced order during as well as 90 minutes and 24 hours after the intervention. Potential underlying mechanisms were evaluated with transcranial magnetic stimulation. Results tDCS facilitated the acquisition of a new motor skill compared with sham stimulation (P=0.04) yielding better task retention results. A significant correlation was observed between the tDCS-induced improvement during training and the tDCS-induced changes of intracortical inhibition (R2=0.63). Conclusions These results indicate that tDCS is a promising tool to improve not only motor behavior, but also procedural learning. They further underline the potential of noninvasive brain stimulation as an adjuvant treatment for long-term recovery, at least in patients with mild functional impairment after stroke. PMID:22618381

  3. Robust optical speed tracking control of a current sensor less synchronous reluctance motor drive using a new sliding mode controller

    International Nuclear Information System (INIS)

    This paper describes the robust optimal incremental motion control of a current sensor less synchronous reluctance motor, which can be specified by any desired speed profile. The control scheme is a combination of conventional linear quadratic feed back control method and sliding mode control. A novel sliding switching surface is employed first, that makes the states of the synchronous reluctance motor follow the nominal trajectories (controlled by any type of nominal controller) when the motor parameter uncertainties and the disturbance load torque exist. The sliding mode controller has no reaching phase and produces small sliding mode control chattering. Then, using the above tracking controller, the well-known torque control schemes, maximum torque, constant current inductive axis control and maximum power factor control related to the synchronous reluctance motor are examined below and above the base speed. Finally the validity of our proposed control scheme is verified by computer simulation results

  4. Generation of complex motor patterns in american grasshopper via current-controlled thoracic electrical interfacing.

    Science.gov (United States)

    Giampalmo, Susan L; Absher, Benjamin F; Bourne, W Tucker; Steves, Lida E; Vodenski, Vassil V; O'Donnell, Peter M; Erickson, Jonathan C

    2011-01-01

    Micro-air vehicles (MAVs) have attracted attention for their potential application to military applications, environmental sensing, and search and rescue missions. While progress is being made toward fabrication of a completely human-engineered MAV, another promising approach seeks to interface to, and take control of, an insect's nervous system. Cyborg insects take advantage of their innate exquisite loco-motor, navigation, and sensing abilities. Recently, several groups have demonstrated the feasibility of radio-controlled flight in the hawkmoth and beetle via electrical neural interfaces. Here, we report a method for eliciting the "jump" response in the American grasshopper (S. Americana). We found that stimulating the metathoracic T3 ganglion with constant-current square wave pulses with amplitude 186 ± 40 μA and frequency 190 ± 13 Hz reproducibly evoked (≥95% success rate) the desired motor activity in N=3 test subjects. To the best of our knowledge, this is the first report of an insect cyborg with a synchronous neuromuscular system. PMID:22254549

  5. Preventive maintenance basis: Volume 11 -- Direct current electric motors. Final report

    International Nuclear Information System (INIS)

    US nuclear plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This report provides an overview of the PM Basis project and describes use of the PM Basis database. Volume 11 of the report provides a program of PM tasks suitable for application to DC (direct current) electric motors in nuclear power plants. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

  6. Speed Control of Brushless Dc Motor Using Current Fed Quasi Z-source Inverter with Regeneration Capability

    Directory of Open Access Journals (Sweden)

    A. Santhi Mary Antony

    2015-06-01

    Full Text Available Current fed Quasi Z-Source Inverters (qZSI have the advantages of voltage buck-boost capability, improved reliability, reduced passive component ratings, continuous input current, a common dc rail between source and inverter and unique regeneration capability. This current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. Since current fed quasi Z Source Inverter has many advantages it can be employed for motor drive applications such as Brushless DC motor (BLDC drive. Therefore this study proposes the use of qZSI for BLDC motor. The simulation results for the same are presented in this study.

  7. Comparison of experimental and theoretical reaction rail currents, rail voltages, and airgap fields for the linear induction motor research vehicle

    Science.gov (United States)

    Elliott, D. G.

    1977-01-01

    Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.

  8. Current control method for zero torque ripple and maximum efficiency of brushless dc motor; Brushless DC motor no zero torque ripple saidai koritsuka denryu seigyoho

    Energy Technology Data Exchange (ETDEWEB)

    Chigiri, T.; Shimada, T.; Watanabe, T.; Ichinokura, O.; Jinzenji, T. [Tohoku University, Sendai (Japan)

    1996-11-20

    Since the rare metal magnets show the high saturation flux density, the ferrite magnets of the magnetic field poles of PM (permanent magnet) motors have been substituted for them in recent years. The feature of the rare metal magnet realize small size or high power BLM (brushless dc motors). However, the ordinary magnetic field poles of the PM motors generate higher harmonic flux and cause torque ripple. They are usually removed by short pitch winding, skew slot method and so on. But these methods show a drawback to lower efficiency. This problem is important especially for high power BLM. Recently new methods have been proposed to realize zero torque ripple and high efficiency drive at the same time. The methods optimize the reference current waveform which is calculated by motor ENE (electromotive force) in advance, and current are controlled to follow up the optimized one. However, the one method assumes try and error. The other one doesn`t prove that it realizes maximum efficiency and zero torque ripple drive at the same time. And they have much room to improvement to apply to BLM. This paper proposes the simultaneous equations which give the accurate relation among instantaneous torque, EW and current, and proposes a new index CSR which evaluates the relation between copper loss and current waveform. Then the optimized current waveform to drive BLM with zero torque ripple and maximum efficiency is calculated by using new equations and CSR. For this waveform includes triplex harmonic order, normal three phase full bridge inverter can`t be used. This paper proposes four arm full bridge inverter which can apply triplex order current to BLM. Experimental result proves this method is available. 9 refs., 11 figs., 2 tabs.

  9. Impact Analysis of Dwell Angles on Current Shape and Torque in Switched Reluctance Motors

    Directory of Open Access Journals (Sweden)

    Syeda Fatima Ghousia

    2012-03-01

    Full Text Available The reduction of torque ripple is the main target in research for designing a variable drive system with switched reluctance motors (SRM for higher torque density and better efficiency. This ripple is due to the transition of excitation current between the adjacent phases. Precise control of turn-on and turn off angle is required to smooth the torque. In this paper, the effects of selecting the turn-on and turn-off angles are simulated in detail. It is observed that with the extended turn-on and turn off angles, the precise selection of turn-on and turn off angle can alter the shape of the excitation current in the stator coil and its point of overlapping with the adjacent coil. Therefore the transition between different phases can be smoothed out. The impact of this alteration on the excitation current and torque ripple as a function of different parameters of dwell angle is studied in detail in this paper. It is found that a sinusoidal current shape can also be obtained with the proper selection of these parameters.

  10. Note: Fast compact laser shutter using a direct current motor and three-dimensional printing

    Science.gov (United States)

    Zhang, Grace H.; Braverman, Boris; Kawasaki, Akio; Vuletić, Vladan

    2015-12-01

    We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade's range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than 108 cycles.

  11. Note: Fast compact laser shutter using a direct current motor and three-dimensional printing

    International Nuclear Information System (INIS)

    We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade’s range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than 108 cycles

  12. Note: Fast compact laser shutter using a direct current motor and three-dimensional printing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Grace H., E-mail: ghzhang0@mit.edu; Braverman, Boris; Kawasaki, Akio; Vuletić, Vladan [Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-12-15

    We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade’s range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than 10{sup 8} cycles.

  13. Advanced valve motor operator diagnostic system [motor current signature analysis] M.C.S.A/[valve motor operator diagnostic system] VMODS

    International Nuclear Information System (INIS)

    This paper explains Wyle's new system for diagnostics, signature analysis and direct measurement of actual load on Motor Operated Valves (MOV) in the closed direction. The following topics are discussed: System description, System capabilities, and Features. The specific features of Wyle's system are: Measures directly the actual closing force; Easy to install; Leap frog working feature minimizes test time; Capability of up to 14-channel simultaneous input and acquisition; Non-intrusive monitoring at a remote location [motor control center (MCC)]; High sensitivity and selectivity to a variety of mechanical disorders affecting MOV operational readiness; and Provision of useful and trendable signature features

  14. 30 CFR 77.900 - Low- and medium-voltage circuits serving portable or mobile three-phase alternating current...

    Science.gov (United States)

    2010-07-01

    ... portable or mobile three-phase alternating current equipment; circuit breakers. 77.900 Section 77.900... mobile three-phase alternating current equipment; circuit breakers. Low- and medium-voltage circuits supplying power to portable or mobile three-phase alternating current equipment shall be protected...

  15. Antibacterial effect of alternating current against Staphylococcus aureus and Pseudomonas aeroginos

    Directory of Open Access Journals (Sweden)

    Mehdi Mirzaii

    2015-05-01

    Full Text Available Background — The use of physical means as an aid for modern medicine in the champion against pathogenic microorganisms holds new approach that recently have begun to be widely recognized. The use of an additional physical means, alternating currents, introduced to inhibit bacterial growth and enhance disinfectant potency. The present study aimed to determine the best frequency of alternating currents in prevention of bacterial growth and to detect the efficacy of alternating currents on disinfectant bactericidal potency. Material and Methods — Electric field strength of 6 and 10 V/cm2 at 50 KHz, 1 MHz, 10 MHz and 20 MHz was applied continuously during lag phases of staphylococcus aureus and pseudomonas aeroginosa. Then Changes in bacterial growth were investigated by the time kill method. Efficacy alternating currents on the current disinfectants bactericidal potency (microzed, deconex, Dettol and glutaraldehyde were evaluated by MIC and MBC. Results — Alternating current at the low voltage and high frequency (10 V/cm2 at 20 MHz reduced the growth of S. aureus and P. aeruginosa effectively. Electric field strength of 10 V/cm2 at 20 MHz showed a better effect on the low level disinfectants such as Dettol and Deconex compared to the high level disinfectants such as Glutaraldehyde, Microzed GP-H and Aniosyme. Conclusion — Detection of a suitable form of alternating current is necessary in the future. This method may be applied as a complementary for eliminating of conductive and semi-conductive surfaces of hospital and increase disinfectant bactericidal potency.

  16. A novel solid-state control system for the minimization of re-switching transient currents of induction motor

    International Nuclear Information System (INIS)

    This work is an investigation into the minimizing re-closure transient currents of induction motors by activating NOVEL solid state control system switching at a matched condition. This emphasis is placed upon-circuit transition starting of cage motors, particularly star-delta switching. The initial study is carried out on single-phase induction motion. This system is capable of effective sensing re-closure of a switched off running single-phase induction motor. Further this scheme could be developed to give sequential delta closure of a switched off running three-phase induction motor during 1st cycles following the opening of the star mode. Consideration is also given to the possibility of using sensed re-closure to minimize transient whenever the supply to a running induction motor is briefly interrupted, irrespective of whether the interruption is by accident design. A brief study is made into the type of transient currents generated by opening the circuit of a running induction motor. The importance of the switching pattern for star-delta starting is explained and emphasized. (author)

  17. Method and apparatus for reducing the harmonic currents in alternating-current distribution networks

    Science.gov (United States)

    Beverly, Leon H.; Hance, Richard D.; Kristalinski, Alexandr L.; Visser, Age T.

    1996-01-01

    An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution network and a load. The apparatus and method also employs a mechanism for increasing the source neutral impedance of the AC source distribution network. This mechanism can consist of a choke installed in the neutral line between the AC source and the Zig-Zag transformer.

  18. Minimization and identification of conducted emission bearing current in variable speed induction motor drives using PWM inverter

    Indian Academy of Sciences (India)

    A Ramachandran; M Channa Reddy; Ranjan Moodithaya

    2008-10-01

    The recent increase in the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applicatons in process and aerospace industries, but due to fast switching of the modern power electronic devices, the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrical instruments and give rise to the flow of bearing current in the induction motor. Due to the flow of bearing current in the induction motor, electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the conducted and radiated emissions become a major concern. In this paper, identification of bearing current due to conducted emission, the measurement of bearing current in a modified induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line impedance stabilization network (LISN)), the electronics interface circuits are used to measure high frequency common mode current, bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at the same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with frequency Vs, line voltage in $dB{_\\mu} V$, common mode voltage in $dB{_\\mu} V$ and the bearing current in $dB_{\\mu} A$ with out and with minimizing circuits.

  19. Theoretical modeling of NO electrochemical reduction on multifunctional layer electrode by alternating/direct current electrolysis

    International Nuclear Information System (INIS)

    Highlights: • Mechanistic modeling of nitrogen oxide electrochemical reduction. • Fundamentals of both alternative and direct current electrolysis. • Theoretical optimal frequency in alternative current electrolysis. - Abstract: A one-dimensional symmetric model on NO electrochemical reduction in solid oxide electrolysis cell(SOEC) considering gas transport, electronic conduction, ionic conduction, and electrochemical process based on multifunctional layer electrode is developed. The simulation results agree well with the experimental results both in the direct current(DC) and alternative current(AC) electrolysis. The distributions of the NO concentration in the electrode are predicted in both DC and AC electrolysis. The effects of temperature, voltage, and O2 concentration were investigated on NO alternative current electrolysis and direct current electrolysis processes. The modeling results show that the optimal frequency of 0.3 Hz is corresponded to the maximum NO decomposition rate in different temperatures and voltages. The NO decomposition increases with increasing temperature and decreasing O2 concentration in most cases. At 450 °C, the NO decomposition presents first increased and then decreased trend with different voltages at the frequency of 0.3 Hz. This is similar to the effects of O2 concentration at 450 °C and 475 °C at the same frequency

  20. Gravity Compensation Technique Uses Small dc Motor

    Science.gov (United States)

    Hollow, Richard

    1988-01-01

    Small dc servomotor powered by simple constant-current source and with suitable gearing used to cancel effect of gravity upon load. Lead-screw positioning system has load counterbalanced by small supplementary motor powered by constant current source. Motor lighter and more compact alternative to counterbalance. Used in variety of mechanical systems where load positioned or accelerated in vertical plane.

  1. A Comparative Study of Pre-computed Current Methods for Torque Ripple Minimisation in Switched Reluctance Motor

    OpenAIRE

    Venkatesha, L; Ramanarayanan, V.

    2000-01-01

    One of the few drawbacks of Switched Reluctance Motor (SRM) is the high torque ripple when compared to the conventional AC and DC drives. In this paper, some of the precomputed current methods for torque ripple minimization in SRM are compared with the method proposed by the authors. The approach to the problem of finding the current trajectories to minimise the torque ripple in different proposed schemes are briefly explained. For all the schemes considered for comparison, the current tra...

  2. Effect of decreasing electrical resistance in Characeae cell membranes caused by the flow of alternating current

    Directory of Open Access Journals (Sweden)

    Edward Śpiewla

    2014-02-01

    Full Text Available By means of the techniques of external electrodes and microelectrodes, it was found that evanescent flow of an alternating current through plasmalemma of Characeae cells neutralises oscillatory change in their electrical resistance and reversibly diminishes its value. This effect is particularly significant in the case of "high resistance cells", but it weakens with increasing temperature. The value of the estimated activation energy indicates that, after flow of the alternating current through the membrane, a rapid increase in the conductivity may be caused by an increase in conductivity of potassium channels. This result seems to support the hypothesis of electroconformational feedback.

  3. Performance Evaluation of Photo-Voltaic fed Brushless Direct Current Motor for Agricultural applications

    Directory of Open Access Journals (Sweden)

    B.V.A.S.S.R.Krishna

    2015-10-01

    Full Text Available This work presents an effective approach towards reduction of steps in power conversion from solar photovoltaic system to load. When a Photovoltaic system is fed to an induction motor, it requires MPPT controller and an Inverter circuit in first and second stages since Induction motor works with a.c supply. By eliminating the Inverter circuit and employing a BLDC motor the efficiency of the system can be improved. The BLDC motor works under Electronic commutation principle with VSI embedded in the motor. A PV Panel fed to the "R" load with Hill Climbing MPPT is considered along with practical irradiance data. Simulation is carried out by formulating the mathematical model for the photovoltaic source, MPPT, Motor. System performance‟s are investigated under different levels of solar insolation

  4. Anodal transcranial direct current stimulation enhances the effects of motor imagery training in a finger tapping task.

    Science.gov (United States)

    Saimpont, Arnaud; Mercier, Catherine; Malouin, Francine; Guillot, Aymeric; Collet, Christian; Doyon, Julien; Jackson, Philip L

    2016-01-01

    Motor imagery (MI) training and anodal transcranial direct current stimulation (tDCS) applied over the primary motor cortex can independently improve hand motor function. The main objective of this double-blind, sham-controlled study was to examine whether anodal tDCS over the primary motor cortex could enhance the effects of MI training on the learning of a finger tapping sequence. Thirty-six right-handed young human adults were assigned to one of three groups: (i) who performed MI training combined with anodal tDCS applied over the primary motor cortex; (ii) who performed MI training combined with sham tDCS; and (iii) who received tDCS while reading a book. The MI training consisted of mentally rehearsing an eight-item complex finger sequence for 13 min. Before (Pre-test), immediately after (Post-test 1), and at 90 min after (Post-test 2) MI training, the participants physically repeated the sequence as fast and as accurately as possible. An anova showed that the number of sequences correctly performed significantly increased between Pre-test and Post-test 1 and remained stable at Post-test 2 in the three groups (P strength within the primary motor cortex could have been reinforced by the association of MI training and tDCS compared with MI training alone and tDCS alone. PMID:26540137

  5. The technique of entropy optimization in motor current signature analysis and its application in the fault diagnosis of gear transmission

    International Nuclear Information System (INIS)

    Nowadays, Motor Current Signature Analysis (MCSA) is widely used in the fault diagnosis and condition monitoring of machine tools. However, although the current signal has lower SNR (Signal Noise Ratio), it is difficult to identify the feature frequencies of machine tools from complex current spectrum that the feature frequencies are often dense and overlapping by traditional signal processing method such as FFT transformation. With the study in the Motor Current Signature Analysis (MCSA), it is found that the entropy is of importance for frequency identification, which is associated with the probability distribution of any random variable. Therefore, it plays an important role in the signal processing. In order to solve the problem that the feature frequencies are difficult to be identified, an entropy optimization technique based on motor current signal is presented in this paper for extracting the typical feature frequencies of machine tools which can effectively suppress the disturbances. Some simulated current signals were made by MATLAB, and a current signal was obtained from a complex gearbox of an iron works made in Luxembourg. In diagnosis the MCSA is combined with entropy optimization. Both simulated and experimental results show that this technique is efficient, accurate and reliable enough to extract the feature frequencies of current signal, which provides a new strategy for the fault diagnosis and the condition monitoring of machine tools.

  6. On the possible role of stimulation duration for after-effects of transcranial alternating current stimulation

    OpenAIRE

    Stefan Rach; Toralf Neuling; Herrmann, Christoph S.

    2015-01-01

    Transcranial alternating current stimulation is a novel method that allows application of sinusoidal currents to modulate brain oscillations and cognitive processes. Studies in humans have demonstrated tACS after-effects following stimulation durations in the range of minutes. However, such after-effects are absent in animal studies using much shorter stimulation protocols in the range of seconds. Thus, stimulation duration might be a critical parameter for after-effects to occur. To test thi...

  7. Studying Effects of Transcranial Alternating Current Stimulation on Hearing and Auditory Scene Analysis

    NARCIS (Netherlands)

    Riecke, Lars

    2016-01-01

    Recent studies have shown that perceptual detection of near-threshold auditory events may depend on the relative timing of the event and ongoing brain oscillations. Furthermore, transcranial alternating current stimulation (tACS), a non-invasive and silent brain stimulation technique, can entrain co

  8. An investigation of the dynamic behaviors of an MRE isolator subjected to constant and alternating currents

    Science.gov (United States)

    Shi, H. F.; Yu, M.; Zhu, M.; Fu, J.; Choi, S. B.; Xing, Z. W.

    2016-07-01

    This paper presents the dynamic behaviors of a magneto-rheological elastomer (MRE) isolator by applying constant and time-varying exciting currents. As the first step, a shear type of the MRE isolator is devised with a simplified design. Then, the distributions of the magnetic field in the MRE isolator under both constant and alternating exciting currents are analyzed by commercial software (ANSYS). Subsequently, the dynamic performances of the isolator are experimentally evaluated by applying three different inputs: constant, square and sinusoidal exciting current. It has been identified from the experimental results that the constant exciting current can provide optimal performances in static control, while the MRE isolator presents more advantages in dynamic control with the sine wave current excitation. This means that an attenuation coefficient of alternating current should be considered to achieve a better dynamic control effect. On the other hand, it has also been demonstrated that alternating the magnetic field can provide a broader variable range of the viscous damping coefficient than that under constant magnetic field.

  9. Adding effect of current displacement and magnetic circuit saturation in an asynchronous motor mathematical model

    Directory of Open Access Journals (Sweden)

    I.A. Tsodik

    2014-04-01

    Full Text Available A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.

  10. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul

    2005-01-01

    A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency...... needed to adjust the speed of the motor. The integrated motor drive concept is a result of merging the two units in order to achieve the following benefits [1-3]: reducing the design and the commissioning time in complex industrial equipments, no need for a cabinet to host the frequency converter, no...... induction motor as a boost inductor for a PFC (Power Factor Correction) stage controlled by the inverter zero-sequence voltage component. By determining how much energy is possible to store in a corner inductor, it is proven that integrating the magnetics into the stator yoke is a feasible solution...

  11. Motor current signature analysis detects airgap eccentricity problems in 3.3 kV 670 HP induction motor driven pumps

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, W.T. [EM Diagnostics Ltd., Alford, Scotland (United Kingdom)

    2005-07-01

    This paper presented industrial case histories to demonstrate the application of Motor Current Signature Analysis (MCSA) to reliably detect airgap eccentricity in 3-phase induction motors. Two types of airgap eccentricity exist simultaneously. The first is static eccentricity where the position of minimum radial airgap length is fixed, and the second is dynamic eccentricity where the minimum airgap revolves with the rotor and is a function of space and time. The causes of both types of airgap eccentricity were described along with the differences between the two. The resultant steady force on the rotor in one direction called unbalanced magnetic pull was also discussed along with the unique frequency components in the airgap flux waveform which induce current components in the stator winding. It was noted that if the level of airgap eccentricity is not kept within a specified limit, then both types of eccentricity cause excessive stressing of the motor resulting in increased bearing wear. In addition, the radial magnetic force waves produced by eccentricity also act on the stator core assembly and rotor cage, thereby subjecting the stator and rotor windings to harmful vibration. MCSA was used to identify the characteristic current signature pattern that indicates abnormal levels of airgap eccentricity. An equation used to identify the current signature pattern was presented. The magnitudes of the rotor slot passing frequency components are a function of airgap eccentricity and are also affected by other factors such as rotor slot design, rotor bar skew, magnetic saturation, magneto motive force distribution, operating load, stator winding asymmetry, stator winding impedance, and voltage supply unbalance. It was concluded that MCSA can reliably detect unacceptable running levels of airgap eccentricity. The technology can be assessed by a hand held and user friendly MCSA instrument called the Iris CS Meter, which has on-line diagnostics to detect broken rotor bars

  12. Alternate but do not swim: a test for executive motor dysfunction in Parkinson disease.

    Science.gov (United States)

    Falchook, Adam D; Decio, Danilo; Williamson, John B; Okun, Michael S; Malaty, Irene A; Rodriguez, Ramon L; Heilman, Kenneth M

    2011-07-01

    The objective of this study is to learn if participants with Parkinson disease (PD), when compared to normal controls, are impaired in making simultaneous but independent right and left hand movements. Participants were tested with Luria's Alternating Hand Postures (AHP) test and modified AHP tests. Twelve PD participants without dementia and twelve matched controls were assessed for their ability to perform the parallel AHP test (both hands remaining in the same coronal plane) and with modifications of this test into swimming (alternative arm extension with finger extension and arm flexion with finger flexion) and reverse swimming (alternative arm extension-finger flexion and arm flexion-finger extension) movements. The participants with PD were significantly impaired when performing the parallel and the reverse swimming movements AHP tests, but not impaired on the swimming movements AHP test. Swimming movements may be phylogenetically and ontogenetically more primitive and not as heavily dependent on frontal-basal ganglia networks; thus performance of swimming movements during the parallel AHP test may decrease this test's sensitivity. PMID:22882811

  13. System and method for motor speed estimation of an electric motor

    Science.gov (United States)

    Lu, Bin; Yan, Ting; Luebke, Charles John; Sharma, Santosh Kumar

    2012-06-19

    A system and method for a motor management system includes a computer readable storage medium and a processing unit. The processing unit configured to determine a voltage value of a voltage input to an alternating current (AC) motor, determine a frequency value of at least one of a voltage input and a current input to the AC motor, determine a load value from the AC motor, and access a set of motor nameplate data, where the set of motor nameplate data includes a rated power, a rated speed, a rated frequency, and a rated voltage of the AC motor. The processing unit is also configured to estimate a motor speed based on the voltage value, the frequency value, the load value, and the set of nameplate data and also store the motor speed on the computer readable storage medium.

  14. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    OpenAIRE

    Jelena Loncarski; Mats Leijon; Milan Srndovic; Claudio Rossi; Gabriele Grandi

    2015-01-01

    The standard solution for the traction system in battery powered electric vehicles (EVs) is a two-level (2L) inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L) inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple redu...

  15. Improved Eddy-current Field Loss Model and Scaling Index for Magnets of Permanent Magnet Synchronous Motors

    OpenAIRE

    Zhang Lei; Gao Chunxia

    2015-01-01

    The paper gives detailed systematic researches on the mechanism and key factors of eddy-current losses in rotor magnets of high power-density permanent magnet synchronous motors(PMSMs). Firstly, this paper establishes quantitative mathematic model of eddy-current losses for surface-mounted PMSM based on eddy current field model and Maxwell equations. Then, a scaling index is put forward to weigh the key factors relevant to the eddy-current losses in magnets. At the same time, the principles o...

  16. Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials

    Science.gov (United States)

    Grimes, D.J.; Marranzino, A.P.

    1968-01-01

    Two spectrographic methods are used in mobile field laboratories of the U. S. Geological Survey. In the direct-current arc method, the ground sample is mixed with graphite powder, packed into an electrode crater, and burned to completion. Thirty elements are determined. In the spark method, the sample, ground to pass a 150-mesh screen, is digested in hydrofluoric acid followed by evaporation to dryness and dissolution in aqua regia. The solution is fed into the spark gap by means of a rotating-disk electrode arrangement and is excited with an alternating-current spark discharge. Fourteen elements are determined. In both techniques, light is recorded on Spectrum Analysis No. 1, 35-millimeter film, and the spectra are compared visually with those of standard films.

  17. Increased resting state connectivity between ipsilesional motor cortex and contralesional premotor cortex after transcranial direct current stimulation with physical therapy.

    Science.gov (United States)

    Chen, Joyce L; Schlaug, Gottfried

    2016-01-01

    Non-invasive stimulation of the brain using transcranial direct current stimulation (tDCS) during motor rehabilitation can improve the recovery of movements in individuals with stroke. However, the neural substrates that underlie the clinical improvements are not well understood. In this proof-of-principle open-label pilot study, five individuals with stroke received 10 sessions of tDCS while undergoing usual care physical/occupational therapy for the arm and hand. Motor impairment as indexed by the Upper Extremity Fugl Meyer assessment was significantly reduced after the intervention. Resting state fMRI connectivity increased between ipsilesional motor cortex and contralesional premotor cortex after the intervention. These findings provide preliminary evidence that the neural underpinnings of tDCS coupled with rehabilitation exercises, may be mediated by interactions between motor and premotor cortex. The latter, of which has been shown to play an important role in the recovery of movements post-stroke. Our data suggest premotor cortex could be tested as a target region for non-invasive brain-stimulation to enhance connectivity between regions that might be beneficial for stroke motor recovery. PMID:26980052

  18. Use of Biosensors as Alternatives to Current Regulatory Methods for Marine Biotoxins

    Directory of Open Access Journals (Sweden)

    Luis M. Botana

    2009-11-01

    Full Text Available Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in European food and there are no legal requirements or technical approaches available to identify their presence. The need for alternative methods to the bioassay is clearly important, and biosensors have become in recent years a feasible alternative to animal sacrifice. This review will discuss the advantages and disadvantages of using biosensors as alternatives to animal assays for marine toxins, with particular focus on surface plasmon resonance (SPR technology.

  19. Study on Current Sensorless Vector Control Method for Electric Vehicle Drive Motor

    OpenAIRE

    Xiaoyong Shen; Linhui Li; Jing Chang; Yafu Zhou; Jing Lian

    2013-01-01

    With the aggravation of environment pollution and the reduction of petroleum resources, the development of electric vehicle (EV) draws more and more people’s attention. In the EV research field, that seeking for a high efficient and reliable motor control method that suits the operating conditions and characteristics of the vehicle drive motor has become one of the key techniques that need to be broken through urgently. Owing to the problems that the efficient work area is narrow and it leads...

  20. Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

    International Nuclear Information System (INIS)

    Highlights: → Very high removal efficiency of cadmium was achieved by electrocoagulation. → Alternating current (AC) avoids oxide layer and corrosion on anode surface. → Good current transfer between anode and cathode results more removal efficiency. → Compact treatment facility and complete automation. → Aluminum alloy anode prevents residual aluminum in treated water. - Abstract: In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl-1 was achieved at a current density of 0.2 A/dm2 and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

  1. Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Subramanyan, E-mail: vasudevan65@gmail.com [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India); Lakshmi, Jothinathan; Sozhan, Ganapathy [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India)

    2011-08-15

    Highlights: {yields} Very high removal efficiency of cadmium was achieved by electrocoagulation. {yields} Alternating current (AC) avoids oxide layer and corrosion on anode surface. {yields} Good current transfer between anode and cathode results more removal efficiency. {yields} Compact treatment facility and complete automation. {yields} Aluminum alloy anode prevents residual aluminum in treated water. - Abstract: In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl{sup -1} was achieved at a current density of 0.2 A/dm{sup 2} and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

  2. Eyes wide shut: Transcranial alternating current stimulation drives alpha rhythm in a state dependent manner

    OpenAIRE

    Philipp Ruhnau; Toralf Neuling; Marco Fuscá; Herrmann, Christoph S.; Gianpaolo Demarchi; Nathan Weisz

    2016-01-01

    Transcranial alternating current stimulation (tACS) is used to modulate brain oscillations to measure changes in cognitive function. It is only since recently that brain activity in human subjects during tACS can be investigated. The present study aims to investigate the phase relationship between the external tACS signal and concurrent brain activity. Subjects were stimulated with tACS at individual alpha frequency during eyes open and eyes closed resting states. Electrodes were placed at Cz...

  3. Corporate Bond Financing of Real Estate Investments - A currently viable alternative to bank loans in Sweden?

    OpenAIRE

    Mårtensson, Viktor; Åström., Ragnar

    2013-01-01

    After the recent financial crisis real estate companies in Sweden experienced difficulties obtaining funding for both new projects as well as refinancing of current investments. The situation in the credit market has since then improved but the refinancing problems that real estate companies experienced during this time has made firms aware of this risk and many companies now seek to diversify their funding sources. This thesis discusses the usage of corporate bonds as an alternative funding ...

  4. Effects of direct and alternating current on the treatment of oily water in an electroflocculation process

    OpenAIRE

    A. A. Cerqueira; P. S. A. Souza; M. R. C. Marques

    2014-01-01

    In the direct current mode (DC), widely used in electroflocculation (EC), the formation of an impermeable oxide layer on the cathode causes the declining of the efficiency of this process. This disadvantage has been reduced by adopting alternating current (AC). In this study, the effects of AC and DC on operational parameters such as the removal of oils and greases (O&G), color and turbidity from oil-in-water (O/W) emulsions of the petroleum industry using aluminum electrodes were investigate...

  5. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan;

    2014-01-01

    Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating......, synchronized with simultaneously recorded current and voltage waveforms. Dynamic details of the novel non-equilibrium discharge are revealed, which is characterized by a sinusoidal current waveform with amplitude stabilized at around 200 mA intermediate between thermal arc and glow discharge, shedding light to...

  6. Transcranial Alternating Current Stimulation in Patients with Chronic Disorder of Consciousness: A Possible Way to Cut the Diagnostic Gordian Knot?

    Science.gov (United States)

    Naro, Antonino; Bramanti, Placido; Leo, Antonino; Russo, Margherita; Calabrò, Rocco Salvatore

    2016-07-01

    Unresponsive wakefulness syndrome (UWS) is a chronic disorder of consciousness (DOC) characterized by a lack of awareness and purposeful motor behaviors, owing to an extensive brain connectivity impairment. Nevertheless, some UWS patients may retain residual brain connectivity patterns, which may sustain a covert awareness, namely functional locked-in syndrome (fLIS). We evaluated the possibility of bringing to light such residual neural networks using a non-invasive neurostimulation protocol. To this end, we enrolled 15 healthy individuals and 26 DOC patients (minimally conscious state-MCS- and UWS), who underwent a γ-band transcranial alternating current stimulation (tACS) over the right dorsolateral prefrontal cortex. We measured the effects of tACS on power and partial-directed coherence within local and long-range cortical networks, before and after the protocol application. tACS was able to specifically modulate large-scale cortical effective connectivity and excitability in all the MCS participants and some UWS patients, who could be, therefore, considered as suffering from fLIS. Hence, tACS could be a useful approach in supporting a DOC differential diagnosis, depending on the level of preservation of the cortical large-scale effective connectivity. PMID:27062669

  7. Mixed eccentricity diagnosis in Inverter-Fed Induction Motors via the Adaptive Slope Transform of transient stator currents

    Science.gov (United States)

    Pons-Llinares, J.; Antonino-Daviu, J.; Roger-Folch, J.; Moríñigo-Sotelo, D.; Duque-Pérez, O.

    2014-10-01

    This paper researches the detection of mixed eccentricity in Inverter-Fed Induction Motors. The classic FFT method cannot be applied when the stator current captured is not in steady state, which is very common in these motors. Therefore, a transform able to detect the time-frequency evolutions of the components present in the transient signal captured must be applied. In order to optimize the result, a method to calculate the theoretical time-frequency evolution of the stator current components is presented, using only the captured current. This previously obtained information enables the use of the proposed transform: the Adaptive Slope Transform, based on appropriately choosing the atom slope in each point analyzed. Thanks to its adaptive characteristics, the time-frequency evolution of the main components in a stator transient current is traced precisely and with high detail in the 2D time-frequency plot obtained. As a consequence, the time-frequency plane characteristic patterns produced by the Eccentricity Related Harmonics are easily and clearly identified enabling a reliable diagnosis. Moreover, the problem of quantifying the presence of the fault is solved presenting a simple and easy to apply method. The transform capabilities have been shown successfully diagnosing an Inverter-Fed Induction Motor with mixed eccentricity during a startup, a decrease in the assigned frequency, and a load variation with and without slip compensation.

  8. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    Science.gov (United States)

    Gallegos-Lopez, Gabriel; Nagashima, James M.; Perisic, Milun; Hiti, Silva

    2012-06-05

    A system is provided for controlling two alternating current (AC) machines via a five-phase PWM inverter module. The system comprises a first control loop, a second control loop, and a current command adjustment module. The current command adjustment module operates in conjunction with the first control loop and the second control loop to continuously adjust current command signals that control the first AC machine and the second AC machine such that they share the input voltage available to them without compromising the target mechanical output power of either machine. This way, even when the phase voltage available to either one of the machines decreases, that machine outputs its target mechanical output power.

  9. Production of alcohols and other oxygenates from fossil fuels and renewables : final report for IEA Alternative Motor Fuels Agreement Program of research and development on alternative motor fuels, Annex 4/Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Vancea, L. (comp.) [Natural Resources Canada, Ottawa, ON (Canada)

    1995-07-01

    The objective of the International Energy Agency's (IEA's) Alternative Motor Fuels Agreement Program was to exchange information on the production of alcohols and other oxygenates between 6 participating countries including Canada, Italy, Japan, New Zealand, Sweden and the United States. Various production methods were reviewed in an effort to identify potential areas of cooperative research programs. The original scope was to examine the production of alcohols and other oxygenates from fossil fuels only, but some participants examined their production from renewables. This report provided a brief description of the Annex and the list of participants. It presented the Operating Agent's Report and contained a summary of the contributions submitted by participating countries by topic. In Canada, Iogen of Ottawa, Ontario has conducted a study on the energy, carbon and economic budgets estimated for wheat grain, corn grain, wheat straw, and switchgrass. Iogen has developed a process for fermenting wheat straw and switchgrass into ethanol. Most research has focused on enzymatic hydrolysis processes because of the low yields inherent in dilute acid hydrolysis processes. Enzymes hydrolyze the cellulose to glucose without producing any degradation products, thereby yielding high quantity products with no toxicity. Future bioethanol production will probably be cellulosic-based rather than grain-based. refs., tabs., figs.

  10. Optimization of brushless direct current motor design using an intelligent technique.

    Science.gov (United States)

    Shabanian, Alireza; Tousiwas, Armin Amini Poustchi; Pourmandi, Massoud; Khormali, Aminollah; Ataei, Abdolhay

    2015-07-01

    This paper presents a method for the optimal design of a slotless permanent magnet brushless DC (BLDC) motor with surface mounted magnets using an improved bee algorithm (IBA). The characteristics of the motor are expressed as functions of motor geometries. The objective function is a combination of losses, volume and cost to be minimized simultaneously. This method is based on the capability of swarm-based algorithms in finding the optimal solution. One sample case is used to illustrate the performance of the design approach and optimization technique. The IBA has a better performance and speed of convergence compared with bee algorithm (BA). Simulation results show that the proposed method has a very high/efficient performance. PMID:25841938

  11. Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

    OpenAIRE

    Bo Long; Shin Teak Lim; Ji Hyoung Ryu; Kil To Chong

    2013-01-01

    Regenerative braking provides an effective way of extending the driving range of battery powered electric vehicles (EVs). This paper analyzes the equivalent power circuit and operation principles of an EV using regenerative braking control technology. During the braking period, the switching sequence of the power converter is controlled to inverse the output torque of the three-phase brushless direct-current (DC) motor, so that the braking energy can be returned to the battery. Compared with ...

  12. Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording

    Directory of Open Access Journals (Sweden)

    James eDowsett

    2016-03-01

    Full Text Available Transcranial alternating current stimulation (tACS has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01. In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.

  13. Continuous electromagnetic separation of inclusion from aluminum melt using alternating current

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel scheme about the continuous electromagnetic purification of aluminum melt was put forward based on the utilization of a square separation pipe and a 50 Hz alternating current to produce electromagnetic force. It is experimentally found that with electrical current of 400 A/cm2, it takes only 10 s to remove 95% inclusion from aluminum melt. Comprehensive numerical simulations were carried out to investigate the dynamics mechanisms behind the process. The results show that the removal of inclusion is attributed to the cooperative effects of electromagnetic buoyancy and the secondary flow induced by the rotational electromagnetic force, and the removal efficient increases with the size of inclusion and the electrical current imposed. Theoretical predictions on the distribution and removal efficiency of inclusion were supported by the experiments.

  14. 30 CFR 75.900 - Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit...

    Science.gov (United States)

    2010-07-01

    ... Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers. Low- and medium-voltage power circuits serving three-phase alternating current equipment shall be... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Low- and medium-voltage circuits serving...

  15. Environmental cost-effectiveness of bio diesel production in Greece: Current policies and alternative scenarios

    International Nuclear Information System (INIS)

    Following European Directive 2003/30/EC, the Greek Government adapted legislation that introduces and regulates the bio diesel market. The implemented quota scheme allocates the country's annual, predetermined, tax exempt production of bio diesel to industries based on their ability to meet several criteria. A number of bio diesel supply chain stakeholders have criticized this policy for being efficiency-robbing and vague. This paper uses 2007 data from energy crop farms and three bio diesel-producing companies in order to assess these criticisms. We study the economic and environmental aspects of the currently adopted policy and compare them to three alternative scenarios. We conclude that such criticisms have a merit and that policy makers need to reconsider their alternative options regarding the promotion of bio diesel in transport. Permission of sales directly to local consumers and promotion of forward integration by farmers are efficiency enhancing and environment-friendly means of promoting the use of bio diesel in transport.

  16. Environmental cost-effectiveness of bio diesel production in Greece. Current policies and alternative scenarios

    International Nuclear Information System (INIS)

    Following European Directive 2003/30/EC, the Greek Government adapted legislation that introduces and regulates the bio diesel market. The implemented quota scheme allocates the country's annual, predetermined, tax exempt production of bio diesel to industries based on their ability to meet several criteria. A number of bio diesel supply chain stakeholders have criticized this policy for being efficiency-robbing and vague. This paper uses 2007 data from energy crop farms and three bio diesel-producing companies in order to assess these criticisms. We study the economic and environmental aspects of the currently adopted policy and compare them to three alternative scenarios. We conclude that such criticisms have a merit and that policy makers need to reconsider their alternative options regarding the promotion of bio diesel in transport. Permission of sales directly to local consumers and promotion of forward integration by farmers are efficiency enhancing and environment-friendly means of promoting the use of bio diesel in transport. (author)

  17. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010

    DEFF Research Database (Denmark)

    Adler, Sarah; Basketter, David; Creton, Stuart;

    2011-01-01

    The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on...... methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at...... least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between...

  18. Alternate current interference in pipeline; Interferencia por corrente alternada em dutos

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Joao Hipolito de Lima [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    This paper regards to the concerning that the pipeline operators should take in to account to better understand and control the alternate current interference (AC- interference). Pipelines sharing rights-of-way with AC high voltage power lines are subjected to AC interference that can cause risk for personnel, operational safety and environment. The AC-interference shall be evaluated, in such way that mitigating action can be applied in order to assure the pipeline is operated in a safety way. The AC-interference evaluation should take in to account the pipeline and the electrical generation/transmission design data. Three approaches are considered: the coating integrity, the personnel chock hazards and the pipeline integrity. The coating integrity is affected by the possibility of high-voltage be induced on the pipeline during power line current fault. The operation and maintenance personnel can be prone to chock hazards (touch voltage and step voltage), depending upon the level of the induced voltage on the pipeline and the ground current. An induced voltage evaluation is then necessary to identify AC potentials in pipeline higher than the safe criteria. The pipeline integrity is concerning to the possibility of occurring alternate current corrosion (AC-corrosion) on the pipe wall. This kind of corrosion is still been investigated, and although it is less critical than the direct current corrosion, it can happen in specific situation. Parameters that affect AC-corrosion are discussed in this paper. Finely it is presented a brief guide to evaluate the possibility of occurring AC- interference in a pipeline and a mitigation measures summary. (author)

  19. Electrical Motor Current Signal Analysis using a Modulation Signal Bispectrum for the Fault Diagnosis of a Gearbox Downstream

    International Nuclear Information System (INIS)

    Motor current signal analysis has been an effective way for many years of monitoring electrical machines themselves. However, little work has been carried out in using this technique for monitoring their downstream equipment because of difficulties in extracting small fault components in the measured current signals. This paper investigates the characteristics of electrical current signals for monitoring the faults from a downstream gearbox using a modulation signal bispectrum (MSB), including phase effects in extracting small modulating components in a noisy measurement. An analytical study is firstly performed to understand amplitude, frequency and phase characteristics of current signals due to faults. It then explores the performance of MSB analysis in detecting weak modulating components in current signals. Experimental study based on a 10kw two stage gearbox, driven by a three phase induction motor, shows that MSB peaks at different rotational frequencies can be based to quantify the severity of gear tooth breakage and the degrees of shaft misalignment. In addition, the type and location of a fault can be recognized based on the frequency at which the change of MSB peak is the highest among different frequencies.

  20. Combined transcranial direct current stimulation and homebased occupational therapy of upper limb motor impairment following intracerebral hemorrhage

    DEFF Research Database (Denmark)

    Mortensen, Jesper; Figlewski, Krystian; Andersen, Henning

    2016-01-01

    Purpose: To investigate the combined effect of transcranial direct current stimulation (tDCS) andhome-based occupational therapy on activities of daily living (ADL) and grip strength, inpatients with upper limb motor impairment following intracerebral hemorrhage (ICH). Methods:A double......-blind randomized controlled trial with one-week follow-up. Patients received fiveconsecutive days of occupational therapy at home, combined with either anodal (n ¼ 8) orsham (n ¼ 7) tDCS. The primary outcome was ADL performance, which was assessed with theJebsen–Taylor test (JTT). Results: Both groups improved JTT...... group, from baseline to post-assessment (p ¼ 0.158). Conclusions: Fiveconsecutive days of tDCS combined with occupational therapy provided greater improvementsin grip strength compared with occupational therapy alone. tDCS is a promising add-onintervention regarding training of upper limb motor...

  1. Examination of Periodic Disturbance Current Control Method: Controlling the Beat Phenomenon of DC Voltage Pulsation in Permanent-Magnet Synchronous Motor Drives

    Science.gov (United States)

    Tobari, Kazuaki; Sakamoto, Kiyoshi; Iwaji, Yoshitaka; Kaneko, Daigo; Uematsu, Hajime; Okubo, Tomofumi

    We propose a new beatless control mechanism for permanent-magnet synchronous motor (PMSM) drives. In drive systems, the three-phase voltage source induces a ripple component whose frequency is six times that of the voltage source frequency in the DC voltage. Therefore, if the motor frequency becomes six times the voltage frequency, a beat phenomenon, which causes an increase in the motor current ripple is observed. We analyze the beat phenomenon which causes current ripples and propose a method based on periodic disturbance current regulation, i.e., beatless control. We carry out time-domain simulation and various experiments and demonstrate the effectiveness of the proposed controller.

  2. MINITYPE MACHINING SYSTEM FOR DIAMOND LAPPING & POLISHING BY USING BRUSHLESS DIRECT CURRENT MOTOR AS PRECISE SPINDLE

    Institute of Scientific and Technical Information of China (English)

    FU Huinan; CHEN Dongsheng; ZHAO Yong; LIN Binquan

    2008-01-01

    A minitype precise spindle system which can machine precisely and stably in the process of diamond lapping and polishing is designed. In such minitype spindle system, the brushless DC spindle motor is used to drive the lapping finish table, which is built with fluid dynamic bearings. Some measures have been taken to make the lapping system dynamic balance, and a servo controller which can adjust the speed of motor from 1 200 r/min to 5 400 r/min is designed. Experiments show that the spindle system is reliable and stable for diamond polishing, and the detection results by atomic force microscope(AFM) show that the surfaces of diamond edge's Ra is 6.725 nm and whole diamond average Ra is 3.25 nm.

  3. Contribution to Problems of Emergency Feeding of Induction Motor by Injected Currents

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav; Klíma, J.

    Gaborone : IASTED, 2006, s. 77-82. ISBN 0-88986-616-3. [Proceedings of the IASTED International Conference on Power, Energy,and Applications. Gaborone (BW), 11.09.2006-13.09.2006] R&D Projects: GA ČR(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction motor * emergency operation of electrical drives * stray losses Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  4. Two Phase Emergency Feeding of Induction Motors by Injected Currents-Analysis

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Klíma, J.

    Rio de Janeiro : WSEAS, 2005, s. 1-6. ISBN 960-8457-19-X. [WSEAS International Conference on Power Engineering Systems (ICOPES 2005) /4./. Rio de Janeiro (BR), 25.04.2005-27.04.2005] R&D Projects: GA ČR(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction motor * emergency operation of electrical drives * additional losses Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. Two Phase Emergency Feeding of Induction Motors by Injected Currents-Discussion

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Bendl, Jiří; Klíma, J.

    Rio de Janeiro : WSEAS, 2005, s. 7-12. ISBN 960-8457-19-X. [WSEAS International Conference on Power Engineering Systems (ICOPES 2005) /4./. Rio de Janeiro (BR), 25.04.2005-27.04.2005] R&D Projects: GA ČR(CZ) GA102/04/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction motor * additional losses * parasitic torques Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. Determination of torque-speed-current characteristics of a brushless DC motor by utilizing back-EMF of non-energized phase

    International Nuclear Information System (INIS)

    This paper presents a method to determine the torque constant and the torque-speed-current characteristics of a brushless DC (BLDC) motor by utilizing back-EMF variation of nonenergized phase. It also develops a BLDC motor controller with a digital signal processor (DSP) to monitor its current, voltage and speed in real time. Torque-speed-current characteristics of a BLDC motor are determined by using the proposed method and the developed controller. They are compared with the torque-speed-current characteristics measured by dynamometer experimentally. This research shows that the proposed method is an effective method to determine the torque constant and the torque-speed-current characteristics of the BLDC motor without using dynamometer

  7. Determination of torque-speed-current characteristics of a brushless DC motor by utilizing back-EMF of non-energized phase

    Energy Technology Data Exchange (ETDEWEB)

    Jang, G.H. [Department of Mechanical Engineering, Hanyang University, 17 Haengdangdong, Seongdonggu, Seoul 133-791 (Korea, Republic of)]. E-mail: ghjang@hanyang.ac.kr; Yeom, J.H. [Department of Mechanical Engineering, Hanyang University, 17 Haengdangdong, Seongdonggu, Seoul 133-791 (Korea, Republic of); Kim, M.G. [Department of Mechanical Engineering, Hanyang University, 17 Haengdangdong, Seongdonggu, Seoul 133-791 (Korea, Republic of)

    2007-03-15

    This paper presents a method to determine the torque constant and the torque-speed-current characteristics of a brushless DC (BLDC) motor by utilizing back-EMF variation of nonenergized phase. It also develops a BLDC motor controller with a digital signal processor (DSP) to monitor its current, voltage and speed in real time. Torque-speed-current characteristics of a BLDC motor are determined by using the proposed method and the developed controller. They are compared with the torque-speed-current characteristics measured by dynamometer experimentally. This research shows that the proposed method is an effective method to determine the torque constant and the torque-speed-current characteristics of the BLDC motor without using dynamometer.

  8. Determination of torque speed current characteristics of a brushless DC motor by utilizing back-EMF of non-energized phase

    Science.gov (United States)

    Jang, G. H.; Yeom, J. H.; Kim, M. G.

    2007-03-01

    This paper presents a method to determine the torque constant and the torque-speed-current characteristics of a brushless DC (BLDC) motor by utilizing back-EMF variation of nonenergized phase. It also develops a BLDC motor controller with a digital signal processor (DSP) to monitor its current, voltage and speed in real time. Torque-speed-current characteristics of a BLDC motor are determined by using the proposed method and the developed controller. They are compared with the torque-speed-current characteristics measured by dynamometer experimentally. This research shows that the proposed method is an effective method to determine the torque constant and the torque-speed-current characteristics of the BLDC motor without using dynamometer.

  9. Passivity-based current controller design for a permanent-magnet synchronous motor.

    Science.gov (United States)

    Achour, A Y; Mendil, B; Bacha, S; Munteanu, I

    2009-07-01

    The control of a permanent-magnet synchronous motor is a nontrivial issue in AC drives, because of its nonlinear dynamics and time-varying parameters. Within this paper, a new passivity-based controller designed to force the motor to track time-varying speed and torque trajectories is presented. Its design avoids the use of the Euler-Lagrange model and destructuring since it uses a flux-based dq modelling, independent of the rotor angular position. This dq model is obtained through the three-phase abc model of the motor, using a Park transform. The proposed control law does not compensate the model's workless force terms which appear in the machine's dq model, as they have no effect on the system's energy balance and they do not influence the system's stability properties. Another feature is that the cancellation of the plant's primary dynamics and nonlinearities is not done by exact zeroing, but by imposing a desired damped transient. The effectiveness of the proposed control is illustrated by numerical simulation results. PMID:19426970

  10. Dynamics of single vortex line in the field of external alternative current

    International Nuclear Information System (INIS)

    Motion of a single vortex line in steady state under action of an external force due to alternate transport current, viscosity and pinning forces as well as the Magnus force has been investigated. The presence of the effective vortex mass was also taken into account. The vibrational spectrum of the line had two branches: the low- and high-frequency ones. The latter branch appears due to taking the effective vortex mass into consideration. In present report, the absorption of energy by the vortex, depending on the frequency of external transport current, has been calculated. The frequency dependence of the absorption demonstrates two typical resonance maxima, one of them being due to depinning frequency of the vortex, and the other one due to its cyclotron resonance. The influences of other forces on dynamics of the single vortex line were considered

  11. Air pollution control residues from waste incineration: Current UK situation and assessment of alternative technologies

    International Nuclear Information System (INIS)

    Current disposal options for APC residues in the UK and alternative treatment technologies developed world-wide have been reviewed. APC residues are currently landfilled in the UK where they undergo in situ solidification, although the future acceptability of this option is uncertain because the EU waste acceptance criteria (WAC) introduce strict limits on leaching that are difficult to achieve. Other APC residue treatment processes have been developed which are reported to reduce leaching to below relevant regulatory limits. The Ferrox process, the VKI process, the WES-PHix process, stabilisation/solidification using cementitious binders and a range of thermal treatment processes are reviewed. Thermal treatment technologies convert APC residues combined with other wastes into inert glass or glass-ceramics that encapsulate heavy metals. The waste management industry will inevitably use the cheapest available option for treating APC residues and strict interpretation and enforcement of waste legislation is required if new, potentially more sustainable technologies are to become commercially viable

  12. Adaptive current compensation with nonlinear disturbance observer for single-sided linear induction motor considering dynamic eddy-effect

    Institute of Scientific and Technical Information of China (English)

    DENG Jiang-ming; CHEN Te-fang; CHEN Chun-yang

    2015-01-01

    An adaptive current compensation control for a single-sided linear induction motor (SLIM) with nonlinear disturbance observer was developed. First, to maintaint-axis secondary component flux constant with consideration of the specially dynamic eddy-effect (DEE) of the SLIM, a instantaneously tracing compensation ofm-axis current component was analyzed. Second, adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer (NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.

  13. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    International Nuclear Information System (INIS)

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  14. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

    2015-03-15

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  15. Regional economic impacts of current and proposed management alternatives for Charles M. Russell National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Ishizaki, Asuka; Ritten, John

    2013-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. Charles M. Russell (CMR) National Wildlife Refuge, located in north-central Montana, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for the Refuge must contain an analysis of expected effects associated with current and proposed refuge-management strategies. For refuge CCP planning, an economic analysis provides a means of estimating how current management (No Action Alternative) and proposed management activities (Alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates a refuge’s contribution to the local community; and (2) it can help in determining whether economic effects are or are not a real concern in choosing among management alternatives. It is important to note that the economic value of a refuge encompasses more than just the impacts on the regional economy. Refuges also provide substantial nonmarket values (values for items not exchanged in established markets) such as maintaining endangered species, preserving wetlands, educating future generations, and adding stability to the ecosystem (Carver and Caudill, 2007). However, quantifying these types of nonmarket values is beyond the scope of this study. This report first presents a description of the local community and economy near the Refuge. Next, the methods used to conduct a regional economic impact analysis are described. An analysis of the final CCP management strategies that could affect stakeholders and residents and the local economy is then presented. The refuge management activities of economic concern in this analysis are:

  16. Regional economic impacts of current and proposed management alternatives for Don Edwards National Wildlife Refuge

    Science.gov (United States)

    Richardson, Leslie; Huber, Chris; Koontz, Lynne

    2012-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan. The Comprehensive Conservation Plan must describe the desired future conditions of a Refuge and provide long-range guidance and management direction to achieve refuge purposes. The Don Edwards San Francisco Bay National Wildlife Refuge, located at the south end of California's San Francisco Bay and one of seven refuges in the San Francisco Bay National Wildlife Refuge Complex, is in the process of developing a range of management goals, objectives, and strategies for the Comprehensive Conservation Plan. The Comprehensive Conservation Plan must contain an analysis of expected effects associated with current and proposed Refuge management strategies. For Refuge Comprehensive Conservation Plan planning, a regional economic analysis provides a means of estimating how current management (No Action Alternative) and proposed management activities (alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates the Don Edwards San Francisco Bay National Wildlife Refuge's contribution to the local community, and (2) it can help in determining whether economic effects are or are not a real concern in choosing among management alternatives. This report first presents a description of the local community and economy near the Don Edwards San Francisco Bay National Wildlife Refuge. Next, the methods used to conduct a regional economic impact analysis are described. An analysis of the final Comprehensive Conservation Plan management strategies that could affect stakeholders, residents, and the local economy is then presented. The management activities of economic concern in this analysis are: * Spending in the local community by Refuge visitors; * Refuge personnel salary spending; and * Refuge purchases of goods and services within the local

  17. Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

    Science.gov (United States)

    Holliday, Ezekiel S. (Inventor)

    2014-01-01

    Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

  18. An Approach to Suppressing Both Shaft Voltage and Leakage Current in an AC Motor Driven by a Voltage-Source PWM Inverter

    Science.gov (United States)

    Doumoto, Takafumi; Akagi, Hirofumi

    This paper proposes a practical approach to suppressing both shaft voltage and leakage current in an ac motor driven by a voltage-source PWM inverter. This approach is characterized by using a neutral line of the ac motor. A common-mode inductor is connected between the inverter and the motor. Moreover, a resistor and a capacitor are connected in series between the motor neutral point and the inverter negative dc bus. This unique circuit configuration makes the common-mode inductor effective in reducing the common-mode voltage appearing at the motor terminals. As a result, both shaft voltage and ground current are significantly suppressed with low cost. Over-voltages at the end of a cable can be suppressed by a normal-mode inductor and a resistor which are connected in parallel. The validity and effectiveness of the new approach are verified by experimental results from a 5-kVA laboratory system.

  19. Protein kinase Cγ mediates ethanol withdrawal hyper-responsiveness of NMDA receptor currents in spinal cord motor neurons

    OpenAIRE

    Li, Hui-Fang; Mochly-Rosen, Daria; Kendig, Joan J

    2005-01-01

    The present studies were designed to test the hypothesis that neuronal-specific protein kinase Cγ (PKCγ) plays a critical role in acute ethanol withdrawal hyper-responsiveness in spinal cord.Patch-clamp studies were carried out in motor neurons in neonatal rat spinal cord slices. Postsynaptic currents were evoked by brief pulses of 2 mM N-methyl-D-aspartic acid (NMDA) in the presence of bicuculline methiodide 10 μM; strychnine 5 μM and tetrodotoxin 0.5 μM.Both ethanol depression and withdrawa...

  20. Optimal state feedback control of brushless direct-current motor drive systems based on Lyapunov stability criterion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper develops a unified methodology for a real-time speed control of brushless direct-current motor drive systems in the presence of measurement noise and load torque disturbance. First, the mathematical model and hardware structure of system is established. Next, an optimal state feed back controller using the Kalman filter state estimation technique is derived.This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. Those two algorithms working together can provide a very-high-speed regulation and dynamic response over a wide range of operating conditions.Simulated responses are presented to highlight the effectiveness of the proposed control strategy.

  1. Optimal control of electric drive with simultaneous control inputs for motor current and flux

    Science.gov (United States)

    Pansyuk, V. I.

    1984-08-01

    A detailed mathematical analysis of the optimal control of a dc electric drive with a variable magnetic flux is presented. Expressions are found for the optimal controller. When this controller uses real time microprocessors control hardware, formulas are also derived for the various portions of the optimal process as well as the logic expressions for the switching of these parts of the process. The resulting optimal process differs from previous determinations in that the braking portion, when a resistance moment is present, contains a free run-down (passive braking) region, before and after which there can be regions of active braking, when the motor produces an electromagnetic moment. In one numerical example of step dc motor control, which is used to compare the optimal process found here with one developed earlier, power losses are found to be reduced by 5.44% with the new process. The entire solution of the problem using the procedure presented here reduces to finding the conditional extremum of some function of several variables whose number is no greater than the dimensionality of the system and does not lead to a boundary value problem.

  2. Gastric motor dysfunctions in Parkinson's disease: Current pre-clinical evidence.

    Science.gov (United States)

    Pellegrini, Carolina; Antonioli, Luca; Colucci, Rocchina; Ballabeni, Vigilio; Barocelli, Elisabetta; Bernardini, Nunzia; Blandizzi, Corrado; Fornai, Matteo

    2015-12-01

    Parkinson's disease (PD) is associated with several non-motor symptoms, such as behavioral changes, urinary dysfunction, sleep disorders, fatigue and, above all, gastrointestinal (GI) dysfunction, including gastric dysmotility, constipation and anorectal dysfunction. Delayed gastric emptying, progressing to gastroparesis, is reported in up to 100% of patients with PD, and it occurs at all stages of the disease with severe consequences to the patient's quality of life. The presence of α-synuclein (α-syn) aggregates in myenteric neurons throughout the digestive tract, as well as morpho-functional alterations of the enteric nervous system (ENS), have been documented in PD. In particular, gastric dysmotility in PD has been associated with an impairment of the brain-gut axis, involving the efferent fibers of the vagal pathway projecting directly to the gastric myenteric plexus. The present review intends to provide an integrated overview of available knowledge on the possible role played by the ENS, considered as a semi-autonomous nervous network, in the pathophysiology of gastric dysmotility in PD. Particular attention has been paid review how translational evidence in humans and studies in pre-clinical models are allowing a better understanding of the functional, neurochemical and molecular alterations likely underlying gastric motor abnormalities occurring in PD. PMID:26499757

  3. Motor flight without noise and smells. Electric motors as alternative drives for airgliders; Motorflug ohne Laerm und Gestank. Elektromotoren als alternativer Antrieb fuer Segelflugzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Krampitz, I.

    2003-12-01

    While air gliders are noiseless, they have never been independent. Lange Flugzeugbau GmbH are now offering a high-performance air glider with an electric motor, which may open up a new market. (orig.) [German] Lautlos und unabhaengig - bisher passten diese beiden Begriffe bei Segelflugzeugen nicht zusammen. Man war auf Windenfahrer, Schlepppiloten oder auf einen ausklappbaren Verbrennungsmotor angewiesen. Die Lange Flugzeugbau GmbH bietet jetzt ein Hochleistungssegelflugzeug mit Elektromotor an. Es koennte einen neuen Markt erschliessen. (orig.)

  4. OXYGEN BUBBLE DEVELOPMENT ON A PLATINUM ELECTRODE IN BOROSILICATE GLASS MELT BY THE EFFECT OF ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Jiri Matej

    2014-10-01

    or on alternating reduction and re-forming of oxidic layer on the electrode in the transition range, has been suggested. Start of bubble evolution at low alternating current density has also been observed in simple sodium-calcium-silicate glass melt. A relation between bubble release and platinum corrosion caused by reduced silicon has been suggested

  5. Efficacy of lidocaine lontophoresis using either alternating or direct current in hairless rats.

    Science.gov (United States)

    Nakajima, Atsushi; Wakita, Ryo; Haida, Haruka; Fukayama, Haruhisa

    2013-01-01

    The aim of this study was to determine transport of lidocaine ions through a hairless rat skin in vivo and to compare the efficacy of alternating current (AC) with that of direct current (DC) iontophoresis (IOP). We measured the concentration of lidocaine transported through a cellophane membrane or a hairless rat dorsal skin applying either AC-IOP or DC-IOP. The results revealed that lidocaine concentration increased in a time-dependent manner in vitro in both DC-IOP and AC-IOP. However, the in vivo study showed different tendencies in lidocaine concentration. In the DCIOP group, lidocaine concentration reached its maximum 20 min after current application and then decreased rapidly; the AC-IOP group showed an increase in lidocaine concentration in a time-dependent manner. There were no side effects such as electrical burns in the rats. In conclusion, AC can be applied for long periods and DC for short periods, or their application time can be appropriately scheduled. Our study also suggests the mechanism by which voltage waveforms affect the skin when applied by IOP. In the future, these findings will be a solid foundation for developing various kinds of medical equipment such as scheduled drug delivery system that can easily deliver various types of drug. PMID:24146168

  6. Effects of direct and alternating current on the treatment of oily water in an electroflocculation process

    Directory of Open Access Journals (Sweden)

    A. A. Cerqueira

    2014-09-01

    Full Text Available In the direct current mode (DC, widely used in electroflocculation (EC, the formation of an impermeable oxide layer on the cathode causes the declining of the efficiency of this process. This disadvantage has been reduced by adopting alternating current (AC. In this study, the effects of AC and DC on operational parameters such as the removal of oils and greases (O&G, color and turbidity from oil-in-water (O/W emulsions of the petroleum industry using aluminum electrodes were investigated. Removal efficiencies of 95%, 97% and 99% of O&G, color and turbidity with energy consumption of 0.280 kWh/m³ and electrode consumption of 0.12 g and 0.18 g were achieved at a current density of 3 A, operation time of 3 minutes and initial pH of 9.0 using AC and DC, respectively. In continuous flow tests performed with the same experimental conditions, the electrode consumption at times up to 60 minutes were 1.6 g and 3.4 g using AC and DC, respectively.

  7. TO THE MATTER OF APPRAISAL OF TECHNICAL-ECONOMIC INDICES OF STEEL-MELTING FURNACES OF CONSTANT AND ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Andrej I. Rozhkov

    2010-01-01

    Full Text Available It is shown that using of static thyristor compensation systems improves efficiency, decreases consumption of power and electrodes, but increases the cost of furnaces of alternating current.

  8. Rapid determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration

    Institute of Scientific and Technical Information of China (English)

    XIAO Jun-ping; WANG Xue-feng; ZHOU Qing-xiang; FAN Xiao-yuan; SU Xian-fa; Bai Hua-hua; DUAN Hai-jing

    2007-01-01

    A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol could be transferred into a nitroso-compound by reacting with NaNO2. The titration end-point was obtained by the formation of a sharp cut in the oscillopolarographic with infinitesimal NaNO2 on double platinum electrodes. The results showed that phenol had an excellent linear relationship over the range of 4.82×10-6 -9.65×10-3 mol/L, the RSD of the proposed method was lower than 1.5%, and the spiked recoveries of three real water samples were in the range of 95.6%-106.9%.

  9. Alternating Current Dielectrophoresis Optimization of Pt-Decorated Graphene Oxide Nanostructures for Proficient Hydrogen Gas Sensor.

    Science.gov (United States)

    Wang, Jianwei; Rathi, Servin; Singh, Budhi; Lee, Inyeal; Joh, Han-Ik; Kim, Gil-Ho

    2015-07-01

    Alternating current dielectrophoresis (DEP) is an excellent technique to assemble nanoscale materials. For efficient DEP, the optimization of the key parameters like peak-to-peak voltage, applied frequency, and processing time is required for good device. In this work, we have assembled graphene oxide (GO) nanostructures mixed with platinum (Pt) nanoparticles between the micro gap electrodes for a proficient hydrogen gas sensors. The Pt-decorated GO nanostructures were well located between a pair of prepatterned Ti/Au electrodes by controlling the DEP technique with the optimized parameters and subsequently thermally reduced before sensing. The device fabricated using the DEP technique with the optimized parameters showed relatively high sensitivity (∼10%) to 200 ppm hydrogen gas at room temperature. The results indicates that the device could be used in several industry applications, such as gas storage and leak detection. PMID:26042360

  10. Determination of europium(3) in the presence of Chrome Azurol S by alternating-current polarography

    International Nuclear Information System (INIS)

    The behavior of Eu(3) ions are studied by alternating-current polarography in the presence of a triphenylmethane dye Chrome Azurol S (CAS) in an ammonia buffer solution in a wide range of pH and concentrations. The mechanism of CAS reduction at a dropping mercury electrode is suggested. The studies performed by the saturation curve method and by the method of isomolar series indicate that the ratio of components in the complex formed is 1 : 1. The determination limit for Eu(3) in a 0.1 M NH4Cl solution (pH 7.0) in the presence of CAS is 2.2 x 10-6 M

  11. Learned EEG-based regulation of motor-related brain oscillations during application of transcranial electric currents: feasibility and limitations

    Directory of Open Access Journals (Sweden)

    Surjo R Soekadar

    2014-03-01

    Full Text Available Objective: Transcranial direct current stimulation (tDCS improves motor learning and can influence emotional processing or attention. However, it remained unclear whether learned electroencephalography (EEG-based brain-machine interface (BMI control during tDCS is feasible and how application of transcranial electric currents during BMI control would interfere with feature-extraction of physiological brain signals. Here we tested this combination and evaluated stimulation-dependent artifacts across different EEG frequencies and stability of motor imagery-based BMI control. Approach: Ten healthy volunteers were invited to two BMI-sessions, each comprising two 60-trial blocks. During the trials, modulation of mu-rhythms (8-15Hz associated with motor imagery recorded over C4 was translated into online cursor movements on a computer screen. During block 2, either sham (session A or anodal tDCS (session B was applied at 1mA with the stimulation electrode placed 1cm anterior of C4. Main results: tDCS was associated with a significant signal power increase in the lower frequencies most evident in the signal spectrum of the EEG channel closest to the stimulation electrode. Stimulation-dependent signal power increase exhibited a decay of 12dB per decade, leaving frequencies above 9Hz unaffected. Analysis of BMI control performance did not indicate a difference between blocks and tDCS conditions. Conclusion: Application of tDCS during learned EEG-based self-regulation of brain oscillations above 9Hz is feasible and safe, and might improve applicability of BMI systems in patient populations.

  12. Regional economic analysis of current and proposed management alternatives for Rappahannock River Valley National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Donovan, Ryan

    2009-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan. The Comprehensive Conservation Plan must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. The Rappahannock River Valley National Wildlife Refuge (refuge) is in the process of developing a range of management goals, objectives, and strategies for the Comprehensive Conservation Plan. The Comprehensive Conservation Plan for the refuge must contain an analysis of expected effects associated with current and proposed refuge management strategies. The purpose of this study was to assess the regional economic implications associated with draft Comprehensive Conservation Plan management strategies. Special interest groups and local residents often criticize a change in refuge management, especially if there is a perceived negative impact to the local economy. Having objective data on economic impacts may show that these fears are overstated. Quite often, the extent of economic benefits a refuge provides to a local community is not fully recognized, yet at the same time the effects of negative changes is overstated. Spending associated with refuge recreational activities, such as wildlife viewing and hunting, can generate considerable tourist activity for surrounding communities. Additionally, refuge personnel typically spend considerable amounts of money purchasing supplies in local stores, repairing equipment and purchasing fuel at the local service stations, and reside and spend their salaries in the local community. For refuge Comprehensive Conservation Plan planning, a regional economic assessment provides a means of estimating how current management (no action alternative) and proposed management activities (alternatives) could affect the local economy. This type of analysis provides two critical pieces of

  13. Desing and Real-Time Analysis of a Direct Current Motor Controller

    Directory of Open Access Journals (Sweden)

    Reinier Torres Labrada

    2011-10-01

    Full Text Available The real time analysis of a DC motor controller is addressed. During the functional analysis, deadline and period of tasks were extracted to be used as parameters for Response Time Analysis (RTA. To get the Worst Case Execution Time (WCET each task is stimulated with a random input vector. A great number of computation time samples were recorded and the WCET computed using the Gumbel statistical distribution. With the WCET, deadlines and periods of the task set under analysis a RTA model is evaluated and its results discussed. By modeling the WCET using the Extreme Values Theory (EVT the need of low level analysis for software and an accurate model for hardware is avoided. The method used here is useful for soft real-time systems and could be applied to other hw/sw platforms easily.

  14. Fast Compact Laser Shutter Using a Direct Current Motor and 3D Printing

    CERN Document Server

    Zhang, Grace H; Kawasaki, Akio; Vuletić, Vladan

    2015-01-01

    We present a mechanical laser shutter design that utilizes a DC electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade's range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 $\\pm$ 0.02) m/s with 1 ms activation delay and 10 $\\mu$s jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than $10^8$ cycles.

  15. Open and closed-loop motor control system with incipient broken rotor bar fault detection using current signature

    OpenAIRE

    Refaat, Shady S.; Abu-Rub, Haitham; Saad, M. S.; Iqbal, Atif

    2014-01-01

    Motor drive system is considered the most important asset in industrial applications. Detection of broken rotor bars has long been important but difficult job in detection area of incipient motor faults. The need for highly efficient motor control drive systems becomes more and more important. Motors are controlled in closed-loop or open-loop modes of operation. This paper develops a novel approach for fault-detection scheme of broken rotor bar faults for three-phase induction motor using sta...

  16. Rotor cage fault diagnosis in three-phase induction motors based on a current and virtual flux approach

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Dulce F. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal); Pires, V. Fernao [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal); Martins, J.F. [CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal); Pires, A.J. [Escola Sup. Tecnologia Setubal/Inst. Politecnico Setubal, Setubal (Portugal)]|[LabSEI - Laboratorio de Sistemas Electricos Industriais, Setubal (Portugal)]|[CTS, Faculdade de Ciencias e Tecnologia/UNL, Lisboa (Portugal)

    2009-04-15

    This paper focuses on the detection of a rotor cage fault in a three-phase PWM feed induction motor. In inverter-fed machines there are some difficulties for the detection of a rotor cage fault. These difficulties are due to the fault signature that will be contained in the currents or voltages applied to the machine. In this way, a new approach based on the current and a virtual flux is proposed. The use of the virtual flux allows the improving of the signal to noise ratio. This approach also allows the identification of a rotor cage fault independently of the type of control used in the ac drive. The theoretical principle of this method is discussed. Simulation and experimental results are presented in order to show the effectiveness of the proposed approach. (author)

  17. On the possible role of stimulation duration for after-effects of transcranial alternating current stimulation

    Directory of Open Access Journals (Sweden)

    Stefan Rach

    2015-08-01

    Full Text Available Transcranial alternating current stimulation is a novel method that allows application of sinusoidal currents to modulate brain oscillations and cognitive processes. Studies in humans have demonstrated tACS after-effects following stimulation durations in the range of minutes. However, such after-effects are absent in animal studies using much shorter stimulation protocols in the range of seconds. Thus, stimulation duration might be a critical parameter for after-effects to occur. To test this hypothesis, we repeated a recent human tACS experiment with a short duration. We applied alpha tACS intermittently for one second duration while keeping other parameters identical. The results demonstrate that this very short intermittent protocol did not produce after-effects on amplitude or phase of the electroencephalogram. Since synaptic plasticity has been suggested as a possible mechanism for after-effects, our results indicate that a stimulation duration of one second is too short to induce synaptic plasticity. Future studies in animals are required that use extended stimulation durations to reveal the neuronal underpinnings. A better understanding of the mechanisms of tACS after-effects is crucial for potential clinical applications.

  18. Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells

    International Nuclear Information System (INIS)

    Tumor burden can be pharmacologically controlled by inhibiting cell division and by direct, specific toxicity to the cancerous tissue. Unfortunately, tumors often develop intrinsic pharmacoresistance mediated by specialized drug extrusion mechanisms such as P-glycoprotein. As a consequence, malignant cells may become insensitive to various anti-cancer drugs. Recent studies have shown that low intensity very low frequency electrical stimulation by alternating current (AC) reduces the proliferation of different tumor cell lines by a mechanism affecting potassium channels while at intermediate frequencies interfere with cytoskeletal mechanisms of cell division. The aim of the present study is to test the hypothesis that permeability of several MDR1 over-expressing tumor cell lines to the chemotherapic agent doxorubicin is enhanced by low frequency, low intensity AC stimulation. We grew human and rodent cells (C6, HT-1080, H-1299, SKOV-3 and PC-3) which over-expressed MDR1 in 24-well Petri dishes equipped with an array of stainless steel electrodes connected to a computer via a programmable I/O board. We used a dedicated program to generate and monitor the electrical stimulation protocol. Parallel cultures were exposed for 3 hours to increasing concentrations (1, 2, 4, and 8 μM) of doxorubicin following stimulation to 50 Hz AC (7.5 μA) or MDR1 inhibitor XR9576. Cell viability was assessed by determination of adenylate kinase (AK) release. The relationship between MDR1 expression and the intracellular accumulation of doxorubicin as well as the cellular distribution of MDR1 was investigated by computerized image analysis immunohistochemistry and Western blot techniques. By the use of a variety of tumor cell lines, we show that low frequency, low intensity AC stimulation enhances chemotherapeutic efficacy. This effect was due to an altered expression of intrinsic cellular drug resistance mechanisms. Immunohistochemical, Western blot and fluorescence analysis revealed

  19. Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells

    Directory of Open Access Journals (Sweden)

    Dini Gabriele

    2006-03-01

    Full Text Available Abstract Background Tumor burden can be pharmacologically controlled by inhibiting cell division and by direct, specific toxicity to the cancerous tissue. Unfortunately, tumors often develop intrinsic pharmacoresistance mediated by specialized drug extrusion mechanisms such as P-glycoprotein. As a consequence, malignant cells may become insensitive to various anti-cancer drugs. Recent studies have shown that low intensity very low frequency electrical stimulation by alternating current (AC reduces the proliferation of different tumor cell lines by a mechanism affecting potassium channels while at intermediate frequencies interfere with cytoskeletal mechanisms of cell division. The aim of the present study is to test the hypothesis that permeability of several MDR1 over-expressing tumor cell lines to the chemotherapic agent doxorubicin is enhanced by low frequency, low intensity AC stimulation. Methods We grew human and rodent cells (C6, HT-1080, H-1299, SKOV-3 and PC-3 which over-expressed MDR1 in 24-well Petri dishes equipped with an array of stainless steel electrodes connected to a computer via a programmable I/O board. We used a dedicated program to generate and monitor the electrical stimulation protocol. Parallel cultures were exposed for 3 hours to increasing concentrations (1, 2, 4, and 8 μM of doxorubicin following stimulation to 50 Hz AC (7.5 μA or MDR1 inhibitor XR9576. Cell viability was assessed by determination of adenylate kinase (AK release. The relationship between MDR1 expression and the intracellular accumulation of doxorubicin as well as the cellular distribution of MDR1 was investigated by computerized image analysis immunohistochemistry and Western blot techniques. Results By the use of a variety of tumor cell lines, we show that low frequency, low intensity AC stimulation enhances chemotherapeutic efficacy. This effect was due to an altered expression of intrinsic cellular drug resistance mechanisms. Immunohistochemical

  20. A Simplified Sensorless Vector Control Based on Average DC Bus Current for Fan Motor

    Science.gov (United States)

    Sumita, Satoshi; Tobari, Kazuaki; Aoyagi, Shigehisa; Maeda, Daisuke

    This paper describes a simplified sensorless vector control based on the average DC bus current for PMSM. This method can be used to design a drive control system at a relatively low cost because the microcontroller does not require a precise timer and the calculation load is slight. In the proposed method, one of the two possible current estimation processes is chosen according to the operation mode. First, the controller estimates d-axis current and identifies the back-EMF parameter in the synchronous operation mode at low speeds. The error in the back-EMF identification affects the efficiency of the proposed system, so it needs to be zero. Second, the controller estimates q-axis current in vector control mode. The identified parameter and q-axis current define voltage reference to realize high efficiency drive. The obtained experimental results confirm the effectiveness of the proposed method.

  1. Construction of AC Motor Controllers for NOvA Experiment Upgrades

    CERN Document Server

    Cooley, Patrick

    2012-01-01

    I have been constructing Alternating Current (AC) motor controllers for manipulation of particle beam detectors. The capability and reliability of these motor controllers are essential to the Laboratory's mission of accurate analysis of the particle beam's position. The device is moved in and out of the beam's path by the motor controller followed by the Neutrinos at the Main Injector Off-Axis {\

  2. Alternating Current Stimulation for Vision Restoration after Optic Nerve Damage: A Randomized Clinical Trial

    Science.gov (United States)

    Schittkowski, Michael P.; Antal, Andrea; Ambrus, Géza Gergely; Paulus, Walter; Dannhauer, Moritz; Michalik, Romualda; Mante, Alf; Bola, Michal; Lux, Anke; Kropf, Siegfried; Brandt, Stephan A.; Sabel, Bernhard A.

    2016-01-01

    Background Vision loss after optic neuropathy is considered irreversible. Here, repetitive transorbital alternating current stimulation (rtACS) was applied in partially blind patients with the goal of activating their residual vision. Methods We conducted a multicenter, prospective, randomized, double-blind, sham-controlled trial in an ambulatory setting with daily application of rtACS (n = 45) or sham-stimulation (n = 37) for 50 min for a duration of 10 week days. A volunteer sample of patients with optic nerve damage (mean age 59.1 yrs) was recruited. The primary outcome measure for efficacy was super-threshold visual fields with 48 hrs after the last treatment day and at 2-months follow-up. Secondary outcome measures were near-threshold visual fields, reaction time, visual acuity, and resting-state EEGs to assess changes in brain physiology. Results The rtACS-treated group had a mean improvement in visual field of 24.0% which was significantly greater than after sham-stimulation (2.5%). This improvement persisted for at least 2 months in terms of both within- and between-group comparisons. Secondary analyses revealed improvements of near-threshold visual fields in the central 5° and increased thresholds in static perimetry after rtACS and improved reaction times, but visual acuity did not change compared to shams. Visual field improvement induced by rtACS was associated with EEG power-spectra and coherence alterations in visual cortical networks which are interpreted as signs of neuromodulation. Current flow simulation indicates current in the frontal cortex, eye, and optic nerve and in the subcortical but not in the cortical regions. Conclusion rtACS treatment is a safe and effective means to partially restore vision after optic nerve damage probably by modulating brain plasticity. This class 1 evidence suggests that visual fields can be improved in a clinically meaningful way. Trial Registration ClinicalTrials.gov NCT01280877 PMID:27355577

  3. Resistivity measured by direct and alternating current: why are they different?

    Directory of Open Access Journals (Sweden)

    V. Y. Zadorozhnaya

    2008-11-01

    current. As a result the resistivity measured by direct and alternating current is different. The new algorithm was tested on laboratory measurements data showing its good agreement with theory. The calculation of pore size distribution using IP laboratory data has been presented. The definition of the membrane IP effect is: "Membrane IP is the successive blockage of inter-pore connections due to the excess distribution of ions during current flow".

  4. High-Frequency Parasitic Currents in Inverter-Fed Induction Motor Drive

    Czech Academy of Sciences Publication Activity Database

    Valouch, Viktor; Škramlík, Jiří; Doležel, Ivo

    Xi'an: Xi'an Jiaotong University Press, 2004 - (Wang, Z.), s. 1511-1514 ISBN 7-5605-1869-9. [IPEMC 2004 - International Power Electronics and Motion Control Conference /4./. Xi'an (CN), 14.08.2004-16.08.2004] R&D Projects: GA ČR GA102/03/1363 Keywords : electromagnetic interferences * common mode currents * differential mode currents Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. Current Search: Performance Evaluation and Application to DC Motor Speed Control System Design

    OpenAIRE

    Deacha Puangdownreong

    2013-01-01

    This paper proposes the current search (CS) metaheuristics conceptualized from the electric current flowing through electric networks for optimization problems with continuous design variables. The CS algorithm possesses two powerful strategies, exploration and exploitation, for searching the global optimum. Based on the stochastic process, the derivatives of the objective function is unnecessary for the proposed CS. To evaluate its performance, the CS is tested against several unconstrained...

  6. DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

    Science.gov (United States)

    Nikam, Pravin N.; Deshpande, Vineeta D.

    2016-05-01

    Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

  7. Habituation-Like Decrease of Acetylcholine-Induced Inward Current in Helix Command Neurons: Role of Microtubule Motor Proteins.

    Science.gov (United States)

    Vasil'yeva, Natal'ya A; Murzina, Galina B; Pivovarov, Arkady S

    2015-07-01

    The role of kinesin and dynein microtubule-associated molecular motors in the cellular mechanism of depression of acetylcholine-induced inward chloride current (ACh-current) was examined in command neurons of land snails (Helix lucorum) in response to repeated applications of ACh to neuronal soma. This pharmacological stimulation imitated the protocol of tactile stimulation evoking behavioural habituation of the defensive reaction. In this system, a dynein inhibitor (erythro-9-(2-hydroxy-3-nonyl)adenine, 50 µM) decreased the ACh-current depression rate. Kinesin Eg5 inhibitors (Eg5 inhibitor III, 10 µM and Eg5 inhibitor V, trans-24, 15 µM) reduced the degree of current depression, and Eg5 inhibitor V also reduced the initial rate of depression. The results of electrophysiological experiments in combination with mathematical modelling provided evidence of the participation of dyneins and kinesin Eg5 proteins in the radial transport of acetylcholine receptors in command neurons of H. lucorum in the cellular analogue of habituation. Furthermore, these results suggest that the reciprocal interaction between dynein and kinesin proteins located on the same vesicle can lead to reverse their usual direction of transport (dyneins-in exocytosis and kinesin Eg5-in endocytosis). PMID:25687906

  8. Alternating Current Electrophoretic Deposition of Antibacterial Bioactive Glass-Chitosan Composite Coatings

    Directory of Open Access Journals (Sweden)

    Sigrid Seuss

    2014-07-01

    Full Text Available Alternating current (AC electrophoretic deposition (EPD was used to produce multifunctional composite coatings combining bioactive glass (BG particles and chitosan. BG particles of two different sizes were used, i.e., 2 μm and 20–80 nm in average diameter. The parameter optimization and characterization of the coatings was conducted by visual inspection and by adhesion strength tests. The optimized coatings were investigated in terms of their hydroxyapatite (HA forming ability in simulated body fluid (SBF for up to 21 days. Fourier transform infrared (FTIR spectroscopy results showed the successful HA formation on the coatings after 21 days. The first investigations were conducted on planar stainless steel sheets. In addition, scaffolds made from a TiAl4V6 alloy were considered to show the feasibility of coating of three dimensional structures by EPD. Because both BG and chitosan are antibacterial materials, the antibacterial properties of the as-produced coatings were investigated using E. coli bacteria cells. It was shown that the BG particle size has a strong influence on the antibacterial properties of the coatings.

  9. Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

    Science.gov (United States)

    Su, Guo-Qiang; Wang, Yi-Bo; Song, Bai-Peng; Mu, Hai-Bao; Zhang, Guan-Jun; Li, Feng; Wang, Meng

    2016-06-01

    The luminescence evolution phenomena from alumina ceramic surface in vacuum under high voltage of direct and alternating current are reported, with the voltage covering a large range from far below to close to the flashover voltage. Its time resolved and spatial distributed behaviors are examined by a photon counting system and an electron-multiplying charge-coupled device (EMCCD) together with a digital camera, respectively. The luminescence before flashover exhibits two stages as voltage increasing, i.e., under a relative low voltage (Stage A), the luminescence is ascribed to radiative recombination of hetero-charges injected into the sample surface layer by Schottky effect; under a higher voltage (Stage B), a stable secondary electron emission process, resulting from the Fowler-Nordheim emission at the cathode triple junction (CTJ), is responsible for the luminescence. Spectrum analysis implies that inner secondary electrons within the surface layer of alumina generated during the SSEE process also participate in the luminescence of Stage B. A comprehensive interpretation of the flashover process is formulated, which might promote a better understanding of flashover issue in vacuum.

  10. Bi-frontal transcranial alternating current stimulation in the ripple range reduced overnight forgetting

    Directory of Open Access Journals (Sweden)

    Géza Gergely Ambrus

    2015-09-01

    Full Text Available High frequency oscillations in the hippocampal structures recorded during sleep have been proved to be essential for long-term episodic memory consolidation in both animals and in humans. The aim of this study was to test if transcranial Alternating Current Stimulation (tACS of the dorsolateral prefrontal cortex (DLPFC in the hippocampal ripple range, applied bi-frontally during encoding, could modulate declarative memory performance, measured immediately after encoding, and after a night’s sleep. An associative word-pair learning test, taken from Marshall and colleagues, was used. During an evening encoding phase, participants received 1 mA 140 Hz tACS or sham stimulation over both DLPFCs for 10 minutes while being presented twice with a list of word-pairs. Cued recall performance was investigated 10 minutes after training and the morning following the training session. Forgetting from evening to morning was observed in the sham condition, but not in the 140 Hz stimulation condition. 140 Hz tACS during encoding may have an effect on the consolidation of declarative material.

  11. From amusic to musical?--Improving pitch memory in congenital amusia with transcranial alternating current stimulation.

    Science.gov (United States)

    Schaal, Nora K; Pfeifer, Jasmin; Krause, Vanessa; Pollok, Bettina

    2015-11-01

    Brain imaging studies highlighted structural differences in congenital amusia, a life-long perceptual disorder that is associated with pitch perception and pitch memory deficits. A functional anomaly characterized by decreased low gamma oscillations (30-40 Hz range) in the right dorsolateral prefrontal cortex (DLPFC) during pitch memory has been revealed recently. Thus, the present study investigates whether applying transcranial alternating current stimulation (tACS) at 35 Hz to the right DLPFC would improve pitch memory. Nine amusics took part in two tACS sessions (either 35 Hz or 90 Hz) and completed a pitch and visual memory task before and during stimulation. 35 Hz stimulation facilitated pitch memory significantly. No modulation effects were found with 90 Hz stimulation or on the visual task. While amusics showed a selective impairment of pitch memory before stimulation, the performance during 35 Hz stimulation was not significantly different to healthy controls anymore. Taken together, the study shows that modulating the right DLPFC with 35 Hz tACS in congenital amusia selectively improves pitch memory performance supporting the hypothesis that decreased gamma oscillations within the DLPFC are causally involved in disturbed pitch memory and highlight the potential use of tACS to interact with cognitive processes. PMID:26254878

  12. 40Hz-Transcranial alternating current stimulation (tACS) selectively modulates speech perception.

    Science.gov (United States)

    Rufener, Katharina S; Zaehle, Tino; Oechslin, Mathias S; Meyer, Martin

    2016-03-01

    The present study investigated the functional relevance of gamma oscillations for the processing of rapidly changing acoustic features in speech signals. For this purpose we analyzed repetition-induced perceptual learning effects in 18 healthy adult participants. The participants received either 6Hz or 40Hz tACS over the bilateral auditory cortex, while repeatedly performing a phoneme categorization task. In result, we found that 40Hz tACS led to a specific alteration in repetition-induced perceptual learning. While participants in the non-stimulated control group as well as those in the experimental group receiving 6Hz tACS considerably improved their perceptual performance, the application of 40Hz tACS selectively attenuated the repetition-induced improvement in phoneme categorization abilities. Our data provide causal evidence for a functional relevance of gamma oscillations during the perceptual learning of acoustic speech features. Moreover, we demonstrate that even less than twenty minutes of alternating current stimulation below the individual perceptual threshold is sufficient to affect speech perception. This finding is relevant in that this novel approach might have implications with respect to impaired speech processing in dyslexics and older adults. PMID:26779822

  13. Flicker-Driven Responses in Visual Cortex Change during Matched-Frequency Transcranial Alternating Current Stimulation

    Science.gov (United States)

    Ruhnau, Philipp; Keitel, Christian; Lithari, Chrysa; Weisz, Nathan; Neuling, Toralf

    2016-01-01

    We tested a novel combination of two neuro-stimulation techniques, transcranial alternating current stimulation (tACS) and frequency tagging, that promises powerful paradigms to study the causal role of rhythmic brain activity in perception and cognition. Participants viewed a stimulus flickering at 7 or 11 Hz that elicited periodic brain activity, termed steady-state responses (SSRs), at the same temporal frequency and its higher order harmonics. Further, they received simultaneous tACS at 7 or 11 Hz that either matched or differed from the flicker frequency. Sham tACS served as a control condition. Recent advances in reconstructing cortical sources of oscillatory activity allowed us to measure SSRs during concurrent tACS, which is known to impose strong artifacts in magnetoencephalographic (MEG) recordings. For the first time, we were thus able to demonstrate immediate effects of tACS on SSR-indexed early visual processing. Our data suggest that tACS effects are largely frequency-specific and reveal a characteristic pattern of differential influences on the harmonic constituents of SSRs. PMID:27199707

  14. Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source.

    Science.gov (United States)

    Usmanov, D T; Chen, L C; Yu, Z; Yamabe, S; Sakaki, S; Hiraoka, K

    2015-04-01

    The high-sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NOx (-) (x = 2,3), O3 and HNO3 originating from plasma-excited air were suggested to contribute to the formation of [TNT - H](-) (m/z 226), [TNT - NO](-) (m/z 197) and [TNT - NO + HNO3 ](-) (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26149109

  15. Eyes wide shut: Transcranial alternating current stimulation drives alpha rhythm in a state dependent manner.

    Science.gov (United States)

    Ruhnau, Philipp; Neuling, Toralf; Fuscá, Marco; Herrmann, Christoph S; Demarchi, Gianpaolo; Weisz, Nathan

    2016-01-01

    Transcranial alternating current stimulation (tACS) is used to modulate brain oscillations to measure changes in cognitive function. It is only since recently that brain activity in human subjects during tACS can be investigated. The present study aims to investigate the phase relationship between the external tACS signal and concurrent brain activity. Subjects were stimulated with tACS at individual alpha frequency during eyes open and eyes closed resting states. Electrodes were placed at Cz and Oz, which should affect parieto-occipital areas most strongly. Source space magnetoencephalography (MEG) data were used to estimate phase coherence between tACS and brain activity. Phase coherence was significantly increased in areas in the occipital pole in eyes open resting state only. The lag between tACS and brain responses showed considerable inter-individual variability. In conclusion, tACS at individual alpha frequency entrains brain activity in visual cortices. Interestingly, this effect is state dependent and is clearly observed with eyes open but only to a lesser extent with eyes closed. PMID:27252047

  16. Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus; Mölle, Matthias; Marshall, Lisa; Siebner, Hartwig Roman

    2009-01-01

    individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks...

  17. 75 FR 41521 - Delphi Corporation, Automotive Holding Group, Plant 6, Currently Known as General Motors...

    Science.gov (United States)

    2010-07-16

    ... determination was published in the Federal Register on October 17, 2007 (72 FR 58899). The certification was... on March 3, 2009 (74 FR 9287). At the request of the State agency, the Department reviewed the... Employment and Training Administration Delphi Corporation, Automotive Holding Group, Plant 6, Currently...

  18. Catecholaminergic Fiber Innervation of the Vocal Motor System Is Intrasexually Dimorphic in a Teleost with Alternative Reproductive Tactics.

    Science.gov (United States)

    Ghahramani, Zachary N; Timothy, Miky; Kaur, Gurpreet; Gorbonosov, Michelle; Chernenko, Alena; Forlano, Paul M

    2015-01-01

    Catecholamines, which include the neurotransmitters dopamine and noradrenaline, are known modulators of sensorimotor function, reproduction, and sexually motivated behaviors across vertebrates, including vocal-acoustic communication. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the vocal motor system in the plainfin midshipman fish Porichthys notatus, a seasonal breeding marine teleost that produces vocal signals for social communication. There are 2 distinct male reproductive morphs in this species: type I males establish nests and court females with a long-duration advertisement call, while type II males sneak spawn to steal fertilizations from type I males. Like females, type II males can only produce brief, agonistic, grunt type vocalizations. Here, we tested the hypothesis that intrasexual differences in the number of CA neurons and their fiber innervation patterns throughout the vocal motor pathway may provide neural substrates underlying divergence in reproductive behavior between morphs. We employed immunofluorescence (-ir) histochemistry to measure tyrosine hydroxylase (TH; a rate-limiting enzyme in catecholamine synthesis) neuron numbers in several forebrain and hindbrain nuclei as well as TH-ir fiber innervation throughout the vocal pathway in type I and type II males collected from nests during the summer reproductive season. After controlling for differences in body size, only one group of CA neurons displayed an unequivocal difference between male morphs: the extraventricular vagal-associated TH-ir neurons, located just lateral to the dimorphic vocal motor nucleus (VMN), were significantly greater in number in type II males. In addition, type II males exhibited greater TH-ir fiber density within the VMN and greater numbers of TH-ir varicosities with putative contacts on vocal motor neurons. This strong inverse relationship between the predominant vocal morphotype and the CA innervation of vocal motor neurons suggests

  19. Position sensorless control of DC brushless motor using current sourece PWM inverter; Denryugata PWM inbata wo mochiita DC burashiresu mota no ichi sensaresu seigyoho

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Y.; Tsunehiro, Y.; Yamamura, N. [Nagoya Inst. of Tech. (Japan)

    1996-02-20

    In respect of the construction of motor as the driving source of electric vehicle, there are two means as inverter-driving induction motors and DC brushless motors. Both of said means have the merits and demerits respectively as DC brushless motor has the excellent driving efficiency in low speed region and the advantage to deal with the trouble of inverter by the brake of power generation while the problems thereof are the filed-weakening control like induction motors is difficult in the practical use and a position sensor is necessary. In this paper, the electric vehicle are used as the object of the research for studying the construction and controlling method of brushless motor without position sensor, the control of the constant output in high speed region, and the starting as well as braking methods of the motor. Using current-source PWM inverter is the characteristic of this means. It is indicated by the comparative investigation with respect to the operating characteristics between the present means and the system using voltage-source inverter to the same synchronous machine that for the latter system the filter at the output side is indispensable and the values of the operating characteristics, efficiency, etc., in the brushless control are lower than those of the present means. 7 refs., 9 figs., 1 tab.

  20. Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS).

    Science.gov (United States)

    Fehér, Kristoffer D; Morishima, Yosuke

    2016-01-01

    Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized. PMID:26862814

  1. 46 CFR 169.684 - Overcurrent protection for motors and motor branch circuits.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Overcurrent protection for motors and motor branch... motors and motor branch circuits. (a) Except as provided in paragraph (d) of this section, each motor... motor that is responsive to motor current or to both motor current and temperature may be used. (b)...

  2. Baixo peso ao nascer e alterações no desenvolvimento motor: a realidade atual Low birth weight and motor development outcomes: the current reality

    OpenAIRE

    Priscila Caçola; Tatiana Godoy Bobbio

    2010-01-01

    OBJETIVO: Realizar uma revisão da literatura sobre fatores que influenciam o déficit de desenvolvimento motor em crianças com baixo peso ao nascer. FONTES DE DADOS: Estudos com crianças com baixo peso ao nascer, publicados no período de 1984 a 2008 nas bases de dados Medline e SciELO, usando as palavras chaves "baixo peso ao nascer" e " desenvolvimento motor", na língua inglesa. SÍNTESE DE DADOS: Embora diferenças no desenvolvimento entre crianças nascidas a termo e pré-termo sejam observadas...

  3. Evaluation of Motor Neuron Excitability by CMAP Scanning with Electric Modulated Current.

    Science.gov (United States)

    Araújo, Tiago; Candeias, Rui; Nunes, Neuza; Gamboa, Hugo

    2015-01-01

    Introduction. Compound Muscle Action Potential (CMAP) scan is a noninvasive promissory technique for neurodegenerative pathologies diagnosis. In this work new CMAP scan protocols were implemented to study the influence of electrical pulse waveform on peripheral nerve excitability. Methods. A total of 13 healthy subjects were tested. Stimulation was performed with an increasing intensities range from 4 to 30 mA. The procedure was repeated 4 times per subject, using a different single pulse stimulation waveform: monophasic square and triangular and quadratic and biphasic square. Results. Different waveforms elicit different intensity-response amplitude curves. The square pulse needs less current to generate the same response amplitude regarding the other waves and this effect is gradually decreasing for the triangular, quadratic, and biphasic pulse, respectively. Conclusion. The stimulation waveform has a direct influence on the stimulus-response slope and consequently on the motoneurons excitability. This can be a new prognostic parameter for neurodegenerative disorders. PMID:26413499

  4. Bat algorithm optimized fuzzy PD based speed controller for brushless direct current motor

    Directory of Open Access Journals (Sweden)

    K. Premkumar

    2016-06-01

    Full Text Available In this paper, design of fuzzy proportional derivative controller and fuzzy proportional derivative integral controller for speed control of brushless direct current drive has been presented. Optimization of the above controllers design is carried out using nature inspired optimization algorithms such as particle swarm, cuckoo search, and bat algorithms. Time domain specifications such as overshoot, undershoot, settling time, recovery time, and steady state error and performance indices such as root mean squared error, integral of absolute error, integral of time multiplied absolute error and integral of squared error are measured and compared for the above controllers under different operating conditions such as varying set speed and load disturbance conditions. The precise investigation through simulation is performed using simulink toolbox. From the simulation test results, it is evident that bat optimized fuzzy proportional derivative controller has superior performance than the other controllers considered. Experimental test results have also been taken and analyzed for the optimal controller identified through simulation.

  5. Motion-induced disturbance of auditory-motor synchronization and its modulation by transcranial direct current stimulation.

    Science.gov (United States)

    Ono, Kentaro; Mikami, Yusuke; Fukuyama, Hidenao; Mima, Tatsuya

    2016-02-01

    The timing of personal movement with respect to external events has previously been investigated using a synchronized finger-tapping task with a sequence of auditory or visual stimuli. While visuomotor synchronization is more accurate with moving stimuli than with stationary stimuli, it remains unclear whether the same principle holds true in the auditory domain. Although the right inferior-superior parietal lobe (IPL/SPL), a center of auditory motion processing, is expected to be involved in auditory-motor synchronization with moving sounds, its functional relevance has not yet been investigated. The aim of the present study was thus to clarify whether horizontal auditory motion affects the accuracy of finger-tapping synchronized with sounds, as well as whether the application of transcranial direct current stimulation (tDCS) to the right IPL/SPL affects this. Nineteen healthy right-handed participants performed a task in which tapping was synchronized with both stationary sounds and sounds that created apparent horizontal motion. This task was performed before and during anodal, cathodal and sham tDCS application to the right IPL/SPL in separate sessions. The time difference between the onset of the sounds and tapping was larger with apparently moving sounds than with stationary sounds. Cathodal tDCS decreased this difference, anodal tDCS increased the variance of the difference and sham stimulation had no effect. These results supported the hypothesis that auditory motion disturbs efficient auditory-motor synchronization and that the right IPL/SPL plays an important role in tapping in synchrony with moving sounds via auditory motion processing. PMID:26613559

  6. Optimization of total harmonic current distortion and torque pulsation reduction in high-power induction motors using genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    Arash SAYYAH; Mitra AFLAK; Alireza REZAZADEH

    2008-01-01

    This paper presents a powerful application of genetic algorithm (GA) for the minimization of the total harmonic current distortion (THCD) in high-power induction motors fed by voltage source inverters,based on an approximate harmonic model. That is,having defined a desired fundamental output voltage,optimal pulse patterns (switching angles) are determined to produce the fundamental output voltage while minimizing the THCD. The complete results for the two cases of three and five switching instants in the first quarter period of pulse width modulation (PWM) waveform are presented. Presence of harmonics in the stator excitation leads to a pulsing-torque component. Considering the fact that if the pulsing-torques are at low frequencies,they can cause troublesome speed fluctuations,shaft fatigue,and unsatisfactory performance in the feedback control system,the 5th,7th,11 th,and 13th current harmonics (in the case of five switching angles) are con strained at some pre-specified values,to mitigate the detrimental effects of low-frequency harmonics. At the same time,the THCD is optimized while the required fun-damental output voltage is maintained.

  7. Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

    Directory of Open Access Journals (Sweden)

    Bo Long

    2013-12-01

    Full Text Available Regenerative braking provides an effective way of extending the driving range of battery powered electric vehicles (EVs. This paper analyzes the equivalent power circuit and operation principles of an EV using regenerative braking control technology. During the braking period, the switching sequence of the power converter is controlled to inverse the output torque of the three-phase brushless direct-current (DC motor, so that the braking energy can be returned to the battery. Compared with the presented methods, this technology can achieve several goals: energy recovery, electric braking, ultra-quiet braking and extending the driving range. Merits and drawbacks of different braking control strategy are further elaborated. State-space model of the EVs under energy-regenerative braking operation is established, considering that parameter variations are unavoidable due to temperature change, measured error, un-modeled dynamics, external disturbance and time-varying system parameters, a sliding mode robust controller (SMRC is designed and implemented. Phase current and DC-link voltage are selected as the state variables, respectively. The corresponding control law is also provided. The proposed control scheme is compared with a conventional proportional-integral (PI controller. A laboratory EV for experiment is setup to verify the proposed scheme. Experimental results show that the drive range of EVs can be improved about 17% using the proposed controller with energy-regeneration control.

  8. Current tests of alternative gravity theories: the Modified Newtonian Dynamics case

    OpenAIRE

    Paramos, Jorge; Bertolami, Orfeu

    2006-01-01

    We address the possibility of taking advantage of high accuracy gravitational space experiments in the Solar System and complementary cosmological tests to distinguish between the usual general relativistic theory from the alternative modified Newtonian dynamics paradigm.

  9. Influence of a Transverse Electric Field on the Alternating Currents Rectification Effect in Superstructures with Non-additive Energy Spectrum

    Directory of Open Access Journals (Sweden)

    V.I. Konchenkov

    2015-12-01

    Full Text Available It is investigated the effect of mutual rectification of alternating currents, induced by an electric field of two uniformly polarized electromagnetic waves with different frequencies in two-dimensional superlattice with non-additive energy spectrum under the influence of a constant transverse electric field. The possibility of control of constant component of electric current (amplification, change of sign, suppression by the transverse electric field is shown. The abilities of the practical use of the results are discussed.

  10. Phase separation in carbon-doped MgB2 studied by means of alternating current susceptibility measurements

    International Nuclear Information System (INIS)

    Alternating-current susceptibility measurements were performed on ternary MgB2-xCx (0≤x≤0.1) superconducting compounds. The results are consistent with the presence of macroscopic phase inhomogeneities at extremely low levels of carbon doping (x≥0.04) in agreement with high-resolution synchrotron x-ray powder diffraction measurements. (author)

  11. Alternating current impedance spectroscopic analysis of biofunctionalized vertically-aligned silica nanospring surface for biosensor applications

    Science.gov (United States)

    Timalsina, Yukta P.

    In this dissertation, a process of vertically-aligned (silica) nanosprings (VANS) based biosensor development is presented. Alternating current (AC) impedance spectroscopy has been used to analyze sensor response as a function of saline phosphate (SP) buffer and biological solutions. The sensor is a parallel plate capacitor consisting of two glass substrates coated with indium tin oxide (ITO), where the VANS [or randomly-aligned nanosprings (RANS)] grown on one substrate serve as the dielectric spacer layer. The response of a VANS device as a function of ionic concentration in SP buffer was examined and an equivalent circuit model was developed. The results demonstrated that VANS sensors exhibited greater sensitivity to the changes in SP concentration relative to the ITO sensors, which serve as controls. The biofunctionalized VANS surface via physisorption and the cross-linker method demonstrates the repeatability, specificity, and selectivity of the binding. The physisorption of biotinylated immunoglobulin G (B-IgG) onto the VANS surface simplifies the whole sensing procedure for the detection of glucose oxidase, since the avidin-conjugated glucose oxidase (Av-GOx) can directly be immobilized on the B-IgG. The cross linker method involves the covalent attachment of antibodies onto the functionalized VANS surface via imine bond. The experiments revealed that the VANS sensor response is solely the result of the interaction of target molecule i.e. mouse IgG with the probe layer, i.e. goat antimouse IgG (GalphaM IgG). It was determined that VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls above 100 Hz, which indicates that the addition of biomolecules inhibits the diffusion of ions and changes the effective dielectric response of the VANS via biomolecular polarization. The study of ionic transport in nanosprings suggested that conductance follows a scaling law. It was demonstrated that a VANS-based device

  12. Alternating current thin film electroluminescence in the near infrared from zinc sulfide doped with rare earths

    Science.gov (United States)

    Kale, Ajay

    Near infrared emission (0.7--1.5 mum) of zinc sulfide (ZnS) doped with erbium (Er) or neodymium (Nd) has been studied in alternating current thin film electroluminescent devices (ACTFELDs). The electroluminescent (EL) thin film phosphors were radio frequency planar magnetron sputter deposited by co-sputtering an undoped ZnS target together with a ZnS: 1.5 mole% ErF 3 or ZnS: 1.5 mole% NdF3 target. The ZnS:ErF3 and ZnS:NdF3 thin film phosphors were annealed for one hour in ultra high purity N2 at temperatures ranging from 350--475°C. Annealing at 425°C for 1 hour in nitrogen was the optimal post-deposition treatment for both the ZnS:ErF3, and ZnS:NdF3 thin film phosphors, resulting in EL power densities of 7.5 and 28 muW/cm2 for the 990nm and the 1550nm emission of ZnS:ErF3, respectively. The power densities were 7.5 (750%) and 28 (2800%) times larger than those from the as-deposited films, which exhibited a power density ˜1muW/cm 2 at both wavelengths. In the case of ZnS:NdF3, 26 and 15 muW/cm2 deposited samples. Post-deposition annealing resulted in a 8 and 1.5 times increase in total device efficiency to 0.42 W/W and 0.7 W/W) for ZnS:ErF3 and ZnS:NdF3, respectively. This was attributed to a reduction in the concentration of shallow defects, which leads to a larger effective phosphor field and band bending, an increase in the conduction charge, and a reduction of inelastic scattering of ballistic electrons. While the peak emission wavelengths from Er were independent of annealing temperature, peak shifts were observed for Nd due to hybridization of the 5d-4f orbitals. At annealing temperatures 425°C, the shallow defect states are annealed out, leading to more efficient direct radiative relaxation from the higher lying excited states, and more intense visible luminescence is observed.

  13. COMPARISON THE EFFECT OF SIMULTANEOUS SENSORY STIMULATION AND CURRENT OCCUPATIONAL THERAPY APPROACHES ON MOTOR DEVELOPMENT OF THE INFANTS WITH DOWN SYNDROME

    Directory of Open Access Journals (Sweden)

    Hossein KARIMI

    2010-12-01

    Full Text Available ObjectiveNeuromuscular characteristics in Down syndrome result in generalized muscular hypotonia, developmental delays and sensory integration deficits. The aim of this study was to compare the effects of simultaneous sensory stimulations and current occupational therapy approaches on motor functions development of infants with Down syndrome.Materials & MethodsEighteen infants with Down syndrome, aged 6 -18 months, were evaluated in two groups: intervention group (simultaneous sensory stimulation and occupational therapy and control group (occupational therapy alone. They attended the program 3 times a week for 6 months and each session lasted 45 minutes. Motor functions were assessed before, during, and after intervention in the two groups, using GMFM test.ResultsMean motor function increased in both groups according to the GMFM test (P = 0.000. Comparison of the changes showed that although the mean difference of this variable was higher in the intervention group, the difference was not statistically significant (P = 0.576.Mean motor deficit reduced in both groups during the period of the study,which was statistically significant (P ConclusionEarly use of simultaneous sensory stimulations can improve the quality of motor skills in Down syndrome infants. It is suggested that it may be used as an early intervention in association with other methods in the rehabilitation of these patients. However, more studies in this regard are warranted.Keywords:Down syndrome, Motor development, Occupational therapy, Sensory stimulation.

  14. Tests of an alternating current propulsion subsystem for electric vehicles on a road load simulator

    Science.gov (United States)

    Stenger, F. J.

    1982-01-01

    The test results of a breadboard version of an ac electric-vehicle propulsion subsystem are presented. The breadboard was installed in the NASA Lewis Research Center Road Load Simulator facility and tested under steady-state and transient conditions. Steady-state tests were run to characterize the system and component efficiencies over the complete speed-torque range within the capability of the propulsion subsystem in the motoring mode of operation. Transient tests were performed to determine the energy consumption of the breadboard over the acceleration and cruise portions of SAE J227 and driving schedules B, C, and D. Tests in the regenerative mode were limited to the low-gear-speed range of the two speed transaxle used in the subsystem. The maximum steady-state subsystem efficiency observed for the breadboard was 81.5 percent in the high-gear-speed range in the motoring mode, and 76 percent in the regenerative braking mode (low gear). The subsystem energy efficiency during the transient tests ranged from 49.2 percent for schedule B to 68.4 percent for Schedule D.

  15. Determination of complex formation constants by phase sensitive alternating current polarography: Cadmium-polymethacrylic acid and cadmium-polygalacturonic acid.

    Science.gov (United States)

    Garrigosa, Anna Maria; Gusmão, Rui; Ariño, Cristina; Díaz-Cruz, José Manuel; Esteban, Miquel

    2007-10-15

    The use of phase sensitive alternating current polarography (ACP) for the evaluation of complex formation constants of systems where electrodic adsorption is present has been proposed. The applicability of the technique implies the previous selection of the phase angle where contribution of capacitive current is minimized. This is made using Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) in the analysis of ACP measurements at different phase angles. The method is checked by the study of the complexation of Cd by polymethacrylic (PMA) and polygalacturonic (PGA) acids, and the optimal phase angles have been ca. -10 degrees for Cd-PMA and ca. -15 degrees for Cd-PGA systems. The goodness of phase sensitive ACP has been demonstrated comparing the determined complex formation constants with those obtained by reverse pulse polarography, a technique that minimizes the electrode adsorption effects on the measured currents. PMID:19073101

  16. Optimal power flow tool for mixed highvoltage alternating current and high-voltage direct current systems for grid integration of large wind power plants

    OpenAIRE

    Aragüés Peñalba, Mònica; Egea Àlvarez, Agustí; Galcerán Arellano, Samuel; Gomis Bellmunt, Oriol

    2015-01-01

    This study presents a tool for solving optimal power flows (OPFs) in hybrid high-voltage direct current (HVDC) and high-voltage alternating current (HVAC) systems for grid integration of large wind power plants, located either offshore or onshore. The OPF departs from the assumption that the power being produced from the wind power plants is known, as well as the demand from the AC grid. To model the interaction between the DC and AC grids, the active power conservation is expressed between t...

  17. Including alternative resources in state renewable portfolio standards: Current design and implementation experience

    International Nuclear Information System (INIS)

    As of October 2012, 29 states, the District of Columbia, and Puerto Rico have instituted a renewable portfolio standard (RPS). Each state policy is unique, varying in percentage targets, timetables, and eligible resources. Increasingly, new RPS polices have included alternative resources. Alternative resources have included energy efficiency, thermal resources, and, to a lesser extent, non-renewables. This paper examines state experience with implementing renewable portfolio standards that include energy efficiency, thermal resources, and non-renewable energy and explores compliance experience, costs, and how states evaluate, measure, and verify energy efficiency and convert thermal energy. It aims to gain insights from the experience of states for possible federal clean energy policy as well as to share experience and lessons for state RPS implementation. - Highlights: • Increasingly, new RPS policies have included alternative resources. • Nearly all states provide a separate tier or cap on the quantity of eligible alternative resources. • Where allowed, non-renewables and energy efficiency are being heavily utilized

  18. EVALUATION OF CURRENTLY AVAILABLE ALTERNATIVES TO METHYL BROMIDE FOR ORNAMENTAL CROP PRODUCTION IN FLORIDA

    Science.gov (United States)

    Studies were designed to test the efficacy of the chemical alternatives, Midas™ (iodomethane:chloropicrin (pic) 50:50 [MI 50:50] and 98:2 [MI 98:2], Arysta LifeScience Corp., Cary, NC) and dimethyl disulfide:pic (Paladin™ 79:21 [DMDS], United Phosphorous, Inc., King of Prussia, PA) compared with met...

  19. Motor control for a brushless DC motor

    Science.gov (United States)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  20. Pharmacological modulation of the short-lasting effects of antagonistic direct current-stimulation over the human motor cortex

    Directory of Open Access Journals (Sweden)

    Leila eChaieb

    2012-07-01

    Full Text Available Combined administration of transcranial direct current stimulation (tDCS with either pergolide (PGL or D-cycloserine (D-CYC can prolong the excitability-diminishing effects of cathodal, or the excitability enhancing effect of anodal stimulation for up to 24hrs poststimulation. However, it remains unclear whether the potentiation of the observed aftereffects is dominated by the polarity and duration of the stimulation, or the dual application of combined stimulation and drug administration. The present study looks at whether the aftereffects of oral administration of PGL (a D1/D2 agonist or D-CYC (a partial NMDA receptor agonist, in conjunction with the short duration antagonistic application of tDCS (either 5 min cathodal followed immediately by 5 min anodal or vice versa, that alone only induces short lasting aftereffects, can modulate cortical excitability in healthy human subjects, as revealed by a single-pulse MEP (motor-evoked-potential paradigm. Results indicate that the antagonistic application of DC currents induces short-term neuroplastic aftereffects that are dependent upon the polarity of the second application of short-duration tDCS. The application of D-cycloserine resulted in a reversal of this trend and so consequently a marked inhibition of cortical excitability with the cathodal-anodal stimulation order was observed. The administration of pergolide showed no significant aftereffects in either case. These results emphasise that the aftereffects of tDCS are dependent upon the stimulation orientation, and mirror the findings of other studies reporting the neuroplasticity inducing aftereffects of tDCS, and their prolongation when combined with the administration of CNS active drugs.

  1. Modelling And Simulation Of Four Quadrant Operation Of Three Phase Brushless DC Motor With Hysteresis Current Controller

    OpenAIRE

    SANITA C S, J T KUNCHERIA

    2013-01-01

    Brushless DC (BLDC) motor drives are becoming more popular in industrial, traction applications. This makes the control of BLDC motor in all the four quadrants very vital- The motor is operated in four steady state operating modes of torque-speed plane. To control a BLDC machine it is generally required to measure the speed and position of rotor by using the sensor because the inverter phases, acting at any time, must be commutated depending on the rotor position. Simulation of the proposed m...

  2. ENIAK. Development of a non-motor injector coking test facility for alternative fuels; ENIAK. Entwicklung eines nichtmotorischen Injektorverkokungspruefstands fuer alternative Kraftstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Hajo; Schloss, Heide vom; Yang, Zhi; Grote, Melanie [OWI Oel-Waerme-Institut GmbH, Aachen (Germany). Gruppe Anwendungstechnik

    2013-10-01

    Poor Biodiesel quality, contamination with copper and zinc as well as undesired reactions between (several) additives and biodiesel components are known causes for nozzle fouling. Therefore, among other things, all additives have to pass a no-harm test. The standard fouling tests are two engine tests: the XUD9-test (CEC F-23-01) and the DW-10-test (CEC DF 98-08). The XUD9 is a cost efficient, fast and proven testing method. It uses, however, an obsolete indirect injection diesel engine. The newer DW10 test is complex, costly and designed for high stress. This reduces the engine life and leads to a fuel consumption of approximately 1,000 l per test, both contributing to the high costs of the test. The main goal of the project ENIAK is the development, assembly, commissioning, and evaluation of a non-engine fuel injector test. It uses four complete common rail systems. The injection takes place in four self-designed reactors instead of an engine, and the fuel is not combusted, but re-condensed and pumped in a circle. If the test method proves to be as reliable as expected, it can be used as an alternative test method for injector fouling with low requirements regarding infrastructure on the testing site and sample volume. The project is funded by the the federal ministry of consumer protection, food and agriculture via FNR (''Fachagentur Nachwachsende Rohstoffe'', Agency for Renewable Resources). (orig.)

  3. Validation and quality control of replacement alternatives ?€“ current status and future challenges

    OpenAIRE

    Leist, Marcel; Hasiwa, Nina; Daneshian, Mardas; Hartung, Thomas

    2012-01-01

    Alternatives to animal testing have been developed mainly in the fields of toxicology and vaccine testing. Typical examples are the evaluation of phototoxicity, eye irritation or skin corrosion/irritation of cosmetics and industrial chemicals. However, examples can also be found in other biomedical areas, such the control of the quality of drug preparations for pyrogens or for the control of the production process of biologics, such as botulinum neurotoxin. For regulatory purposes, the qualit...

  4. Oxygen bubble development on a platinum electrode in borosilicate glass melt by the effect of alternating current

    Czech Academy of Sciences Publication Activity Database

    Matěj, J.; Jebavá, Marcela

    2014-01-01

    Roč. 58, č. 4 (2014), s. 249-259. ISSN 0862-5468 R&D Projects: GA TA ČR TA01010844 Institutional support: RVO:67985891 Keywords : glass melt * platinum electrode * alternating current * oxygen bubble Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.435, year: 2014 http://www.ceramics-silikaty.cz/2014/pdf/2014_04_249.pdf

  5. Overview of Alternative Bunching and Current-shaping Techniques for Low-Energy Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Piot, Philippe [Northern Illinois U.

    2015-12-01

    Techniques to bunch or shape an electron beam at low energies (E <15 MeV) have important implications toward the realization of table-top radiation sources [1] or to the design of compact multi-user free-electron lasers[2]. This paper provides an overview of alternative methods recently developed including techniques such as wakefield-based bunching, space-charge-driven microbunching via wave-breaking [3], ab-initio shaping of the electron-emission process [4], and phase space exchangers. Practical applications of some of these methods to foreseen free-electron-laser configurations are also briefly discussed [5].

  6. Alternating current for the West; Un courant alternatif pour le grand ouest

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    In the framework of the reactor EPR construction in the Manche, the authors wonder on the pertinence of this energy choice for the economy and the environment of the West France. They show that there is an alternative to this choice. In a first part a state of the situation concerning the electricity supply and demand in the region is detailed. Then from the local potential of renewable electric power production and the electricity conservation, they propose many concrete actions. (A.L.B.)

  7. New algorithm to detect voltage disturbances in three phases alternative current systems

    Energy Technology Data Exchange (ETDEWEB)

    Benslimane, T.; Chetate, B. [University of Boumerdes (Algeria)

    2006-07-01

    In this paper is presented a new algorithm based on logical functions to detect different disturbances in alternative voltage in electrical power networks such as over-voltage, under-voltage, unbalanced voltage, short circuit besides the safe operating condition. This algorithm is based on RMS values of three phases voltages as input values to detection system that is basically based on logical functions. This system is applied on three phase electrical power network of sinusoidal voltage. It can also be applied on PWM voltage that must be filtered to get its fundamental RMS value. Simulation program was developed in Matlab/Simulinksoftware. Simulation results are presented. (orig.)

  8. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report first provides a description of the local community and economy near Sand Lake NWR. An analysis of current and proposed management strategies that could...

  9. Motor Fuel Excise Taxes

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    A new report from the National Renewable Energy Laboratory (NREL) explores the role of alternative fuels and energy efficient vehicles in motor fuel taxes. Throughout the United States, it is common practice for federal, state, and local governments to tax motor fuels on a per gallon basis to fund construction and maintenance of our transportation infrastructure. In recent years, however, expenses have outpaced revenues creating substantial funding shortfalls that have required supplemental funding sources. While rising infrastructure costs and the decreasing purchasing power of the gas tax are significant factors contributing to the shortfall, the increased use of alternative fuels and more stringent fuel economy standards are also exacerbating revenue shortfalls. The current dynamic places vehicle efficiency and petroleum use reduction polices at direct odds with policies promoting robust transportation infrastructure. Understanding the energy, transportation, and environmental tradeoffs of motor fuel tax policies can be complicated, but recent experiences at the state level are helping policymakers align their energy and environmental priorities with highway funding requirements.

  10. Development of alternating current transmitter of detection system for magnetic material in soil subsurface

    Science.gov (United States)

    Indrasari, Widyaningrum; Djamal, Mitra; Srigutomo, Wahyu; Ramli

    2016-03-01

    Generally, detection system for magnetic material in soil subsurface using electromagnetic induction method consists of two parts, they are transmitter and receiver unit. A transmitter must be able to produce a continuous and stable AC current at a certain frequency, meanwhile receiver should be able to catch the secondary magnetic field of magnetic material in soil subsurface. The aim of this study was to develop a new AC current transmitter of detection system for the magnetic material in soil subsurface. This paper will describe the results of the development of AC current transmitter systems, distance characterization of the sensor detection toward horizontal solenoid positions, and characterization of magnetic material in the soil subsurface. It has successfully made the AC current transmitter system, composed of a sinusoidal signal generator, power amplifier, and a source of AC magnetic field. The output of the generator has a frequency varies: 1 kHz, 2 kHz, 5 kHz, and 10 kHz. We found that the AC current transmitter that has been developed able to work properly up to a frequency of 10 kHz.

  11. Convection displacement current and alternative form of Maxwell-Lorentz equations

    CERN Document Server

    Chubykalo, A E; Chubykalo, Andrew E.; Smirnov-Rueda, Roman

    1996-01-01

    Some mathematical inconsistencies in the conventional form of Maxwell's equations extended by Lorentz for a single charge system are discussed. To surmount these in framework of Maxwellian theory, a novel convection displacement current is considered as additional and complementary to the famous Maxwell displacement current. It is shown that this form of the Maxwell-Lorentz equations is similar to that proposed by Hertz for electrodynamics of bodies in motion. Original Maxwell's equations can be considered as a valid approximation for a continuous and closed (or going to infinity) conduction current. It is also proved that our novel form of the Maxwell-Lorentz equations is relativistically invariant. In particular, a relativistically invariant gauge for quasistatic fields has been found to replace the non-invariant Coulomb gauge. The new gauge condition contains the famous relationship between electric and magnetic potentials for one uniformly moving charge that is usually a! ttributed to the Lorentz transfor...

  12. Multiple-Fault Detection Methodology Based on Vibration and Current Analysis Applied to Bearings in Induction Motors and Gearboxes on the Kinematic Chain

    Directory of Open Access Journals (Sweden)

    Juan Jose Saucedo-Dorantes

    2016-01-01

    Full Text Available Gearboxes and induction motors are important components in industrial applications and their monitoring condition is critical in the industrial sector so as to reduce costs and maintenance downtimes. There are several techniques associated with the fault diagnosis in rotating machinery; however, vibration and stator currents analysis are commonly used due to their proven reliability. Indeed, vibration and current analysis provide fault condition information by means of the fault-related spectral component identification. This work presents a methodology based on vibration and current analysis for the diagnosis of wear in a gearbox and the detection of bearing defect in an induction motor both linked to the same kinematic chain; besides, the location of the fault-related components for analysis is supported by the corresponding theoretical models. The theoretical models are based on calculation of characteristic gearbox and bearings fault frequencies, in order to locate the spectral components of the faults. In this work, the influence of vibrations over the system is observed by performing motor current signal analysis to detect the presence of faults. The obtained results show the feasibility of detecting multiple faults in a kinematic chain, making the proposed methodology suitable to be used in the application of industrial machinery diagnosis.

  13. Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells

    OpenAIRE

    Sheng-Nan Wu; Ming-Chun Hsu; Yu-Kai Liao; Fang-Tzu Wu; Yuh-Jyh Jong; Yi-Ching Lo

    2012-01-01

    Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (I K(DR)) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of I K(DR) inactivation rate was about 9.8  μ M. Neither linopirdine (10  μ M), NMD...

  14. Determination of aniline in environmental water samples by alternating-current oscillopolarographic titration

    Institute of Scientific and Technical Information of China (English)

    Jun Ping Xiao; Qing Xiang Zhou; Xiao Ke Tian; Hua Hua Bai; Xian Fa Su

    2007-01-01

    A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper.Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail.The experimental results indicated that this method was simple, rapid, and sensitive.The linear range was 8.367 x 10-4 to 2.789 x 10-2 mol L-1, the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4-106.9% under the optimal conditions.The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.

  15. Characterization of CdS thin films electrodeposited by an alternating current electrolysis method

    International Nuclear Information System (INIS)

    Conventional electrochemical methods of making CdS films are anodic oxidation of cadmium in a solution containing sulfide ions, and cathodic reduction from solutions containing soluble metal and sulfur compounds. In this paper a method is presented in which a CdS layer is deposited by a.c. electrolysis. The substrate is a glass plate covered by a layer of tin oxide. The electrolyte is an aqueous solution containing cadmium sulphate, ammonium sulphate, sodium thiosulphate, sodium chloride and glycerol. The applied a.c. voltages correspond to symmetrical and asymmetrical rectangular waves. During the electrolysis two electrodes are alternately connected to positive and negative potentials. As a result, Cd/sup 2+/ and S/sup 2-/ particles deposit at each electrode by turns, which results in the formation of a CdS layer

  16. Accelerated test methods for predicting the life of motor materials exposed to refrigerant/lubricant mixtures. Phase 1, Conceptual design: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II; Ferguson, A.

    1993-08-18

    The federally mandated phase-out of chlorofluorocarbon refrigerants requires screening tests for motor materials compatibility with alternative refrigerant/lubricant mixtures. In the current phase of the program, ARTI is supporting tests of promising candidate refrigeration/lubricant systems in key refrigeration component systems such as bearings and hermetic motor insulation systems to screen for more subtle detrimental effects and allow estimates of motor-compressor life. This report covers: mechanisms of failure of hermetic motor insulation, current methods for estimation of life of hermetic motors, and conceptual design of improved stator simulator device for testing of alternative refrigerant/lubricant mixtures.

  17. Research of resisting of the biological active point for constant and alternative current

    Directory of Open Access Journals (Sweden)

    S. N. Peregudov

    2008-05-01

    Full Text Available Is conducted research of resistance of biologically active point (BAT on a direct and variable current. Research results are presented. The estimation of intercommunication between resistance of skin and by an electromagnetic radiation in BAT is done. Is shown possibility of the use of experimental information for diagnostics of the state of human to the organism.

  18. Analysis on operational power and eddy current losses for applying coreless double-sided permanent magnet synchronous motor/generator to high-power flywheel energy storage system

    Science.gov (United States)

    Jang, Seok-Myeong; Park, Ji-Hoon; You, Dae-Joon; Choi, Sang-Ho

    2009-04-01

    This paper deals with analytical approach of operational power defined as load power and rotor loss represented as eddy current loss for applying a permanent magnet (PM) synchronous motor/generator to the high-power flywheel energy storage system. The used model is composed of a double-sided Halbach magnetized PM rotor and coreless three-phase winding stator. For one such motor/generator structure, we provide the magnetic field and eddy current with space and time harmonics via magnetic vector potential in two-dimensional (2D) polar coordinate system. From these, the operational power is estimated by backelectromotive force according to the PM rotor speed, and the rotor loss is also calculated from Poynting theorem.

  19. Use of Superimposed Alternating Currents in Quadrupoles to Measure Beam Position with Respect to their Magnetic Centre

    CERN Document Server

    Marks, N

    2000-01-01

    The positional stability of the electron beam in a modern state-of-the-art synchrotron radiation source is critical, as the many experimental users require consistency in the position and dimensions of the incoming photon beams which are incident on their experimental samples. At the Daresbury Synchrotron Radiation Source (SRS), inaccuracies in the measurements of the positions of both beam position monitors and the lattice quadrupoles can be overcome by measuring the position of the electron beam with respect to the magnetic centres of the quadrupoles. This was achieved by superimposing an alternating ('ripple') current on the direct current excitation of a single lattice quadrupole and examining the resulting beam oscillations at remote positions in the storage ring. If the electron beam is then subjected to a local distortion at the position of this quadrupole, the amplitude of the beam oscillation induced by the superimposed current is minimised (nominally zero) when the beam is at the quadrupole's magnet...

  20. Current guidelines for the laboratory diagnosis of thyroid diseases (radioimmunoassay and alternative immunoassays)

    International Nuclear Information System (INIS)

    The improvements in the sensitivity and specificity of biochemical thyroid tests have dramatically impacted clinical strategies for diagnosis and treating thyroid disorders. This article is designed to give an overview of the current strengths and limitations of the in vitro thyroid tests most commonly used in clinical practice. Despite recent methodological achievements, current thyroid tests still exhibit wide variability and are prone to a variety of technical limitations of which physicians are often unaware. Such problems include binding protein abnormalities that affect the FT4 tests, thyroglobulin autoantibodies that interfere with serum Tg measurement, medications or sever non thyroid illness that have myriad effects on thyroid tests. It is recommended that an active laboratory-physician interface be maintained to ensure that quality, cost-effective assays are used in a logical sequence and to assess abnormal thyroid test results and investigate discordance. These discordance need to be interpreted with care using a collaborative approach between laboratory and physicians. (author)

  1. Conduction Block of Peripheral Nerve Using High Frequency Alternating Currents Delivered through an Intrafascicular Electrode

    OpenAIRE

    Ackermann, D. Michael; Foldes, Emily L.; Bhadra, Niloy; Kilgore, Kevin L.

    2010-01-01

    Many diseases are characterized by undesired or pathological neural activity. The local delivery of high frequency currents has been shown to be an effective method for blocking neural conduction in peripheral nerves and may provide a therapy for these conditions. To date, all studies of high frequency conduction block have utilized extraneural (cuff) electrodes to achieve conduction block. In this study we show that high frequency conduction block is feasible using intrafascicular electrodes.

  2. Use of Biosensors as Alternatives to Current Regulatory Methods for Marine Biotoxins

    OpenAIRE

    Botana, Luis M.; M. Carmen Louzao; Natalia Vilariño; Fonfría, Eva S.

    2009-01-01

    Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids) in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in...

  3. Torque Ripple Minimisation in Switched Reluctance Motors by Optimisation of Current Wave-Forms and of Teeth Shape with Copper Losses and V.A. Silicon Constraints

    OpenAIRE

    Le Chenadec, Jean-Yves; Geoffroy, Marc; Multon, Bernard; Mouchoux, Jean-Claude

    1994-01-01

    The main aim of this paper is the minimisation of torque riplle in a 6/4 switched reluctance motor by current waveforms and pole arc optimisation and with realistic constraints. This research is base on a magnetic structure with several sizes which remain constant: outer diameter (250 mm), stack length (150 mm), shaft diameter (42 mm) and airgap length (0.8 mm). Electromagnetic characteristics of 5 machines are computed by element finite method. Before these computations were computed, the ma...

  4. Transient analysis of converter-fed variable-speed generator-motor for pumped storage power plant. Relationship between fault current and speed variation; Kahensoku yosui hatsuden system no koshoji kato tokusei kaiseki. Kaiten sokudo henka no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, T.; Kageyama, T.; Okamura, K.; Kusunoki, K. [Toshiba Corp., Tokyo (Japan); Taguchi, T.; Abe, M.; Kaneko, H. [Tokyo Electric Power Co. Inc., Tokyo (Japan)

    1995-11-20

    A converter-fed variable-speed generator-motor for a pumped storage power plant has been developed in order to contribute to the automatic frequency control on an electric power system during pumping operations, as well as to improve the efficiency of turbines during generating operation together with electric power stability. This system consists of a reversible pump-turbine, generator-motor, cycloconverter and control units. The rotor of the generator-motor, which is coupled directly with the turbine runner, is normally operated at a rotating speed equal to the difference between the frequency of the electric power system and that of the rotor current. In the state that a fault has occurred in the primary circuit of the generator-motor, the variable-speed rotating speed varies and the generator-motor fault current differs from that of a conventional synchronous generator-motor. We have previously reported the fault current analysis results on the assumption that the rotating-speed of the generator-motor does not vary during the fault. However the rotating-speed of the generator-motor does vary during the fault, therefore this paper describes the fault current analysis results without this assumption for the condition when a sudden short-circuit is made on the primary side or secondary side of the generator-motor, and collates the analysis results with the EMTP simulation results. 8 refs., 10 figs.

  5. THE MOTOR ACTIVITY IN THE SECONDARY SCHOOL IN OUR COUNTRY NOT AFFECTED BY THE CURRENT GLOBAL CRISIS

    Directory of Open Access Journals (Sweden)

    Lecturer MARCONI ROBERTO GABRIEL, Phd

    2012-12-01

    Full Text Available In this period of global crisis the motor activity at the level of the secondary school from our country did not stagnate, on the contrary it achieved a special development due to an increase in the number of stu- dents (pupils eager to practice the motor activity, as a result of the improvement of the material equipment with more than 40 simple and complex stadiums of various gymnastics, judo and karate courts, equipped with minifootball, handball, basketball and volleyabll courts. But the most important thing is to provide professionals belonging to the field of physical education within the Universities of Arad up to the present and also in the future.

  6. Effects of alternating current imposition and alkaline earth elements on modification of primary Mg_2Si crystals in hypereutectic Mg-Si alloy

    Institute of Scientific and Technical Information of China (English)

    DU Jun; K. IWAI; LI Wen-fang; PENG Ji-hua

    2009-01-01

    The effects of alternating current imposition and/or alkaline earth elements on modification of the primary Mg_2Si crystals in the hypereutectic Mg-Si alloy were investigated. An alternating current of 60 A with frequency of 1 kHz was applied into the hypereutectic Mg-Si melt which was alloyed with alkaline earth elements or not in the fixed temperature range from 700 to 630 ℃. The results show that the primary Mg_2Si crystals could be refined by imposing alternating current or adding alkaline elements. Compared with the samples treated by adding 0.4% Ca or 0.4% Sr, higher modification efficiency could be obtained for the samples treated by imposing alternating current. No further modification efficiency could be obtained for the samples treated by imposing alternating current combined with 0.4% Ca or 0.4% Sr addition.

  7. Internal heating of lithium-ion batteries using alternating current based on the heat generation model in frequency domain

    Science.gov (United States)

    Zhang, Jianbo; Ge, Hao; Li, Zhe; Ding, Zhanming

    2015-01-01

    This study develops a method to internally preheat lithium-ion batteries at low temperatures with sinusoidal alternating current (AC). A heat generation rate model in frequency domain is developed based on the equivalent electrical circuit. Using this model as the source term, a lumped energy conservation model is adopted to predict the temperature rise. These models are validated against the experimental results of preheating an 18650 cell at different thermal insulation conditions. The effects of current amplitude and frequency on the heating rate are illustrated with a series of simulated contours of heating time. These contours indicate that the heating rate increases with higher amplitude, lower frequency and better thermal insulation. The cell subjected to an alternating current with an amplitude of 7 A (2.25 C) and a frequency of 1 Hz, under a calibrated heat transfer coefficient of 15.9 W m-2 K-1, can be heated from -20 °C to 5 °C within 15 min and the temperature distribution remains essentially uniform. No capacity loss is found after repeated AC preheating tests, indicating this method incurs little damage to the battery health. These models are computationally-efficient and can be used in real time to control the preheating devices in electric vehicles.

  8. Asynchronous recruitment of low-threshold motor units during repetitive, low-current stimulation of the human tibial nerve

    Directory of Open Access Journals (Sweden)

    Jesse eDean

    2014-12-01

    Full Text Available Motoneurons receive a barrage of inputs from descending and reflex pathways. Much of our understanding about how these inputs are transformed into motor output in humans has come from recordings of single motor units during voluntary contractions. This approach, however, is limited because the input is ill-defined. Herein, we quantify the discharge of soleus motor units in response to well-defined trains of afferent input delivered at physiologically-relevant frequencies. Constant frequency stimulation of the tibial nerve (10-100 Hz for 30 s, below threshold for eliciting M-waves or H-reflexes with a single pulse, recruited motor units in 7/9 subjects. All 25 motor units recruited during stimulation were also recruited during weak (<10% MVC voluntary contractions. Higher frequencies recruited more units (n=3/25 at 10 Hz; n=25/25 at 100 Hz at shorter latencies (19.4±9.4 s at 10 Hz; 4.1±4.0 s at 100 Hz than lower frequencies. When a second unit was recruited, the discharge of the already active unit did not change, suggesting that recruitment was not due to increased synaptic drive. After recruitment, mean discharge rate during stimulation at 20 Hz (7.8 Hz was lower than during 30 Hz (8.6 Hz and 40 Hz (8.4 Hz stimulation. Discharge was largely asynchronous from the stimulus pulses with time-locked discharge occurring at an H-reflex latency with only a 24% probability. Motor units discharged after the stimulation ended in 89% of trials, although at a lower rate (5.8 Hz than during the stimulation (7.9 Hz. This work supports the idea that the afferent volley evoked by repetitive stimulation recruits motor units through the integration of synaptic drive and intrinsic properties of motoneurons, resulting in physiological recruitment which adheres to Henneman's size principle and results in relatively low discharge rates and asynchronous firing.

  9. Potential alternatives to edible oils for biodiesel production - A review of current work

    International Nuclear Information System (INIS)

    Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. Currently, biodiesel is mainly prepared from conventionally grown edible oils such as rapeseed, soybean, sunflower and palm thus leading to alleviate food versus fuel issue. About 7% of global vegetable oil supplies were used for biodiesel production in 2007. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. The use of non-edible plant oils when compared with edible oils is very significant in developing countries because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The production of biodiesel from different non-edible oilseed crops has been extensively investigated over the last few years.

  10. Potential alternatives to edible oils for biodiesel production - A review of current work

    International Nuclear Information System (INIS)

    Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. Currently, biodiesel is mainly prepared from conventionally grown edible oils such as rapeseed, soybean, sunflower and palm thus leading to alleviate food versus fuel issue. About 7% of global vegetable oil supplies were used for biodiesel production in 2007. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. The use of non-edible plant oils when compared with edible oils is very significant in developing countries because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The production of biodiesel from different non-edible oilseed crops has been extensively investigated over the last few years. (author)

  11. Including Alternative Resources in State Renewable Portfolio Standards: Current Design and Implementation Experience

    Energy Technology Data Exchange (ETDEWEB)

    Heeter, J.; Bird, L.

    2012-11-01

    Currently, 29 states, the District of Columbia, and Puerto Rico have instituted a renewable portfolio standard (RPS). An RPS sets a minimum threshold for how much renewable energy must be generated in a given year. Each state policy is unique, varying in percentage targets, timetables, and eligible resources. This paper examines state experience with implementing renewable portfolio standards that include energy efficiency, thermal resources, and non-renewable energy and explores compliance experience, costs, and how states evaluate, measure, and verify energy efficiency and convert thermal energy. It aims to gain insights from the experience of states for possible federal clean energy policy as well as to share experience and lessons for state RPS implementation.

  12. A high-Tc superconducting quantum interference device with an alternating current bias DOIT and additional positive feedback

    International Nuclear Information System (INIS)

    This study shows that the alternating current (AC) bias direct offset integrated technique (DOIT) reduces low-frequency noise without increasing the level of white noise in a high-Tc DC superconducting quantum interference device (SQUID). Additional positive feedback (APF), which can improve the effective flux-to-voltage transfer function, it used to reduce the equivalent flux noise due to the voltage noise of the preamplifier of the magnetometer. The use of APF combined with the AC bias DOIT reduced the noise of the magnetometer by factors of 1.5 at 100 Hz, 3.5 at 10 Hz, and 5.3 at 1 Hz when compared with noise levels obtained with the static current bias DOIT. (author)

  13. Analysis of operations and cyber security policies for a system of cooperating Flexible Alternating Current Transmission System (FACTS) devices.

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Laurence R.; Tejani, Bankim; Margulies, Jonathan; Hills, Jason L.; Richardson, Bryan T.; Baca, Micheal J.; Weiland, Laura

    2005-12-01

    Flexible Alternating Current Transmission Systems (FACTS) devices are installed on electric power transmission lines to stabilize and regulate power flow. Power lines protected by FACTS devices can increase power flow and better respond to contingencies. The University of Missouri Rolla (UMR) is currently working on a multi-year project to examine the potential use of multiple FACTS devices distributed over a large power system region in a cooperative arrangement in which the FACTS devices work together to optimize and stabilize the regional power system. The report describes operational and security challenges that need to be addressed to employ FACTS devices in this way and recommends references, processes, technologies, and policies to address these challenges.

  14. Silver eel migration, wind power and alternating current fields; Blankaalsvandring, vindkraft och vaexelstroemsfaelt, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Lagenfelt, Ingvar; Andersson, Ingemar; Westerberg, Haakan

    2012-02-15

    How are eels affected by large offshore wind farms? The study follows the silver eels' migration and behavior at Lillgrund wind farm in Oeresund and the passage over an 130 kV AC cable between the mainland and Oeland. The aim is to see if the AC cable precludes or otherwise affects the eel's ability to reach its destination. Eels migrate up to 7500 km from the Baltic Sea to spawn in the Sargasso Sea. Every delay is of importance for the silver eels, which must be able to travel the entire distance on a single energy reserve. Fish, which make use of the earth's magnetic field for navigation or which are sensitive to electromagnetic fields, may be affected by AC cables on the seabed. The study shows that the silver eels swimming speed was reduced when there was more current in the cable and there was an average delay of 40 minutes before they passed it

  15. The effects of ultrasound and alternating current on the laser penetration in the tissue.

    Science.gov (United States)

    Dawood, Munqith Saleem

    2016-07-01

    The visible (VIS) and near-infrared (NIR) lasers are now widely used in therapeutic and other medical applications. Some of these applications require to deliver the laser energy deep toward the desired tissue target or organ. The aim of this in vitro study is to investigate practically whether the modulation of laser energy by employing the therapeutic ultrasound or electrical energies can increase the penetration depth of the laser light inside the tissue. Such modulation was implemented in this study by coupling the (c.w.) diode and Nd:YAG laser energies with the ultrasound or AC current simultaneously as they pass through preprepared ex vivo bovine muscular tissue strips. Two wavelengths of diode lasers were used, 637 and 808 nm beside the 1064-nm Nd:YAG laser. The results showed a noticeable decrease of these laser attenuation factors as they pass through the tissue strips in the presence of the ultrasound or AC energies. By using this coupling modulation, the capability of increasing the laser penetration depths inside the tissue was confirmed without having to increase their applied power. PMID:27098338

  16. Augmentative and alternative communication for children with autism spectrum disorder: An evidence-based evaluation of the Language Acquisition through Motor Planning (LAMP programme

    Directory of Open Access Journals (Sweden)

    Mary-Ann Naguib Bedwani

    2015-12-01

    Full Text Available Children diagnosed with autism spectrum disorder often have restricted verbal communication. For children who do not use functional speech, augmentative and alternative communication (AAC devices can be an important support. We evaluated the effectiveness of one AAC programme, the Language Acquisition through Motor Planning (LAMP using a Vantage Lite™ device as the speech output in the home and school environments. Eight children with limited communication were assessed by a speech pathologist prior to the introduction of the programme, after five weeks of training and again after a further two weeks of use of the programme, but without the supported training. The pre-/post-assessment measures revealed that all eight children made gains in the development of spontaneous communication using the device during the implementation period. Parents and teachers also reported that the gains achieved during the five-week trial were greater than those achieved in previous interventions. Two years after the completion of the study, a follow-up phone interview was completed which identified that children who received ongoing support from a LAMP-trained speech pathologist continued using the LAMP programme. As a result of this study, a specialised LAMP-specific classroom was established in one of the participating schools.

  17. Direct Torque Control Algorithm for Induction Motor Using Hybrid Fuzzy-PI and Anti-Windup PI Controller with DC Current Sensors

    Directory of Open Access Journals (Sweden)

    Anju R

    2014-03-01

    Full Text Available In this paper, torque ripple minimization in direct torque control (DTC of three phase Induction Motor (IM using PI, hybrid fuzzy PI and anti-windup PI controller were compared. Speed performance is also improved when the controllers were changed. Reconstruction of phase current method is used in the conventional method, by using this method cost of the sensors is reduced and also basic DTC performance is maintained. The reference speed is used for generating the reference torque with the help of PI controller. The drawback is torque ripple in induction motor by using the existing DTC. In proposed system, controller of hybrid fuzzy-PI and anti-windup PI were implemented for generating the reference torque. The speed performance is improved by hybrid Fuzzy-PI controller and the torque ripples will be minimized by using the anti-windup PI controller. The proposed method is implemented using MATLAB/SIMULINK.

  18. Coordinated switching of bacterial flagellar motors: evidence for direct motor-motor coupling?

    OpenAIRE

    Hu, Bo; Tu, Yuhai

    2013-01-01

    The swimming of Escherichia coli is powered by its multiple flagellar motors. Each motor spins either clockwise (CW) or counterclockwise (CCW), under the control of an intracellular regulator, CheY-P. There can be two mechanisms (extrinsic and intrinsic) to coordinate the switching of bacterial motors. The extrinsic one arises from the fact that different motors in the same cell sense a common input (CheY-P) which fluctuates near the motors' response threshold. An alternative, intrinsic mecha...

  19. Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells

    Directory of Open Access Journals (Sweden)

    Sheng-Nan Wu

    2012-01-01

    Full Text Available Flupirtine (Flu, a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (IK(DR with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of IK(DR inactivation rate was about 9.8 μM. Neither linopirdine (10 μM, NMDA (30 μM, nor gabazine (10 μM reversed Flu-induced changes in IK(DR inactivation. Addition of Flu shifted the inactivation curve of IK(DR to a hyperpolarized potential. Cumulative inactivation for IK(DR was elevated in the presence of this compound. Flu increased the amplitude of M-type K+ current (IK(M and produced a leftward shift in the activation curve of IK(M. In another neuronal cells (NG108-15, Flu reduced IK(DR amplitude and enhanced the inactivation rate of IK(DR. The results suggest that Flu acts as an open-channel blocker of delayed-rectifier K+ channels in motor neurons. Flu-induced block of IK(DR is unlinked to binding to NMDA or GABA receptors and the effects of this agent on K+ channels are not limited to its action on M-type K+ channels.

  20. Electro-optically responsive composites of gold nanospheres in 5CB liquid crystal under direct current and alternating current joint action

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B.; Marinov, Yordan G.; Petrov, Alexander G. [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Bruno, Emanuela [Dipartimento di Fisica, Università della Calabria, Via Pietro Bucci, Cubo 31C, 87036 Rende (CS) (Italy); Marino, Lucia, E-mail: lucia.marino@fis.unical.it [CNR-IPCF UoS di Cosenza, Licryl Laboratory, and Centro di Eccellenza CEMIF.CAL, Università della Calabria, 87036 Rende (CS) (Italy); Scaramuzza, Nicola [Dipartimento di Fisica, Università della Calabria, Via Pietro Bucci, Cubo 31C, 87036 Rende (CS) (Italy); CNR-IPCF UoS di Cosenza, Licryl Laboratory, and Centro di Eccellenza CEMIF.CAL, Università della Calabria, 87036 Rende (CS) (Italy)

    2014-02-28

    Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EO controlled coherent light scattering and diffraction by stationary longitudinal texture pattern (LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated gold spherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperature nematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effective scattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmitted coherent light from a low-power continuous wave laser beam, resulting in a drastic reduction of its local intensity. The effect is polarization dependent and is strongest when the polarization of the input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studied under DC and alternating current (AC) joint action with the aim of the potential use of these composite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DC voltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as the possibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can be useful for EO applications in the field of process control and for detection of weak dynamic electric fields.

  1. Alternating-Current InGaN/GaN Tunnel Junction Nanowire White-Light Emitting Diodes.

    Science.gov (United States)

    Sadaf, S M; Ra, Y-H; Nguyen, H P T; Djavid, M; Mi, Z

    2015-10-14

    The current LED lighting technology relies on the use of a driver to convert alternating current (AC) to low-voltage direct current (DC) power, a resistive p-GaN contact layer to inject positive charge carriers (holes) for blue light emission, and rare-earth doped phosphors to down-convert blue photons into green/red light, which have been identified as some of the major factors limiting the device efficiency, light quality, and cost. Here, we show that multiple-active region phosphor-free InGaN nanowire white LEDs connected through a polarization engineered tunnel junction can fundamentally address the afore-described challenges. Such a p-GaN contact-free LED offers the benefit of carrier regeneration, leading to enhanced light intensity and reduced efficiency droop. Moreover, through the monolithic integration of p-GaN up and p-GaN down nanowire LED structures on the same substrate, we have demonstrated, for the first time, AC operated LEDs on a Si platform, which can operate efficiently in both polarities (positive and negative) of applied voltage. PMID:26384135

  2. Signature of cluster disruption within magnetic fluid samples: The key information provided by low frequency alternating current susceptibility measurements

    Science.gov (United States)

    Du, Zhongzhou; Liu, Wenzhong; Zhong, Jing; Zhou, Ming; Zhang, Pu; Cesar Morais, Paulo

    2014-05-01

    This paper is focused on the signature of thermal-assisted cluster disruption while analyzing the inverse alternating current (AC) susceptibility (1/χ) versus temperature (T) curves recorded at lower AC frequencies (f), below 300 Hz. A commercial oil-based magnetic fluid (MF) sample was used in the experiments to investigate the critical temperature (T*) that characterizes the thermal disruption of aggregates suspended within the MF sample. T* was found to reduce as f increased within the frequency range of our investigation (63-263 Hz). Furthermore, T* was found to scale with the square of the applied AC frequency. Both theoretical and experimental evidences support that the excitation field frequency (f) dependence of the critical temperature (T*) is well described by T*(f)=T*(0)-Af/21+Bf2. The model is based on energy absorption of magnetic nanoparticles in an AC magnetic field.

  3. Elicitors as alternative strategy to pesticides in grapevine? Current knowledge on their mode of action from controlled conditions to vineyard.

    Science.gov (United States)

    Delaunois, Bertrand; Farace, Giovanni; Jeandet, Philippe; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan; Cordelier, Sylvain

    2014-04-01

    Development and optimisation of alternative strategies to reduce the use of classic chemical inputs for protection against diseases in vineyard is becoming a necessity. Among these strategies, one of the most promising consists in the stimulation and/or potentiation of the grapevine defence responses by the means of elicitors. Elicitors are highly diverse molecules both in nature and origins. This review aims at providing an overview of the current knowledge on these molecules and will highlight their potential efficacy from the laboratory in controlled conditions to vineyards. Recent findings and concepts (especially on plant innate immunity) and the new terminology (microbe-associated molecular patterns, effectors, etc.) are also discussed in this context. Other objectives of this review are to highlight the difficulty of transferring elicitors use and results from the controlled conditions to the vineyard, to determine their practical and effective use in viticulture and to propose ideas for improving their efficacy in non-controlled conditions. PMID:23719689

  4. Characterization of interference thin films grown on stainless steel surface by alternate pulse current in a sulphochromic solution

    Directory of Open Access Journals (Sweden)

    Rosa Maria Rabelo Junqueira

    2008-12-01

    Full Text Available The aim of this work was to characterize thin interference films grown on the surface of AISI 304 stainless steel for decorative purposes. Films were grown in a sulphochromic solution at room temperature by an alternating pulse current method. The morphology and chemical state of the elements in the films were investigated by field emission scanning electron microscopy (FESEM, atomic force microscopy (AFM, glow discharge optical emission spectrometry (GDOES, and infrared Fourier transform spectroscopy (FTIR. Depth-sensing indentation (DSI experiments and wear abrasion tests were employed to assess the mechanical resistance of the films. The coloration process resulted in porous thin films which increased the surface roughness of the substrate. The interference films mainly consisted of hydrated chromium oxide containing iron. Increasing film thickness produced different colors and affected the mechanical properties of the coating-substrate system. Thicker films, such as those producing gold and green colors, were softer but more abrasion resistant.

  5. A new laser direct etching method of indium tin oxide electrode for application to alternative current plasma display panel

    International Nuclear Information System (INIS)

    For cost effective fabrication and time of alternative current plasma display panels (AC PDPs), an indium tin oxide (ITO) layer was patterned directly with a Q-switched diode pumped Nd:YVO4 laser (λ = 1064 nm). As experimental results, 500 mm/s scan speed with 40 kHz repetition rate was suitable for the application to AC PDP ITO electrode. In comparison with the chemically wet-etched ITO patterns by photolithography method, laser-ablated ITO patterns showed the formation of shoulders at the edge of the ITO lines and a ripple-like structure of the etched bottom. By dipping the laser-ablated ITO films in the chemical etching solution for 30 s at 50 deg. C, the shoulders were effectively removed without affecting the discharging properties of AC PDP.

  6. Bihemispheric Motor Cortex Transcranial Direct Current Stimulation Improves Force Steadiness in Post-Stroke Hemiparetic Patients: A Randomized Crossover Controlled Trial.

    Science.gov (United States)

    Montenegro, Rafael A; Midgley, Adrian; Massaferri, Renato; Bernardes, Wendell; Okano, Alexandre H; Farinatti, Paulo

    2016-01-01

    Post-stroke patients usually exhibit reduced peak muscular torque (PT) and/or force steadiness during submaximal exercise. Brain stimulation techniques have been proposed to improve neural plasticity and help to restore motor performance in post-stroke patients. The present study compared the effects of bihemispheric motor cortex transcranial direct current stimulation (tDCS) on PT and force steadiness during maximal and submaximal resistance exercise performed by post-stroke patients vs. healthy controls. A double-blind randomized crossover controlled trial (identification number: TCTR20151112001; URL: http://www.clinicaltrials.in.th/) was conducted involving nine healthy and 10 post-stroke hemiparetic individuals who received either tDCS (2 mA) or sham stimulus upon the motor cortex for 20 min. PT and force steadiness (reflected by the coefficient of variation (CV) of muscular torque) were assessed during unilateral knee extension and flexion at maximal and submaximal workloads (1 set of 3 repetitions at 100% PT and 2 sets of 10 repetitions at 50% PT, respectively). No significant change in PT was observed in post-stroke and healthy subjects. Force steadiness during knee extension (~25-35%, P < 0.001) and flexion (~22-33%, P < 0.001) improved after tDCS compared to the sham condition in post-stroke patients, but improved only during knee extension (~13-27%, P < 0.001) in healthy controls. These results suggest that tDCS may improve force steadiness, but not PT in post-stroke hemiparetic patients, which might be relevant in the context of motor rehabilitation programs. PMID:27601988

  7. Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

    Directory of Open Access Journals (Sweden)

    Yuan-Tsung Chen

    2013-10-01

    Full Text Available This investigation studies CoFeB/AlOx/Co magnetic tunneling junction (MTJ in the magnetic field of a low-frequency alternating current, for various thicknesses of the barrier layer AlOx. The low-frequency alternate-current magnetic susceptibility (χac and phase angle (θ of the CoFeB/AlOx/Co MTJ are determined using an cac analyzer. The driving frequency ranges from 10 to 25,000 Hz. These multilayered MTJs are deposited on a silicon substrate using a DC and RF magnetron sputtering system. Barrier layer thicknesses are 22, 26, and 30 Å. The X-ray diffraction patterns (XRD include a main peak at 2θ = 44.7° from hexagonal close-packed (HCP Co with a highly (0002 textured structure, with AlOx and CoFeB as amorphous phases. The full width at half maximum (FWHM of the Co(0002 peak, decreases as the AlOx thickness increases; revealing that the Co layer becomes more crystalline with increasing thickness. χac result demonstrates that the optimal resonance frequency (fres that maximizes the χac value is 500 Hz. As the frequency increases to 1000 Hz, the susceptibility decreases rapidly. However, when the frequency increases over 1000 Hz, the susceptibility sharply declines, and almost closes to zero. The experimental results reveal that the mean optimal susceptibility is 1.87 at an AlOx barrier layer thickness of 30 Å because the Co(0002 texture induces magneto-anisotropy, which improves the indirect CoFeB and Co spin exchange-coupling strength and the χac value. The results concerning magnetism indicate that the magnetic characteristics are related to the crystallinity of Co.

  8. The direct relationship between output power and current carrying capability of rotor bars in HTS induction/synchronous motor with the use of DI-BSCCO tapes

    Science.gov (United States)

    Nakamura, T.; Nagao, K.; Nishimura, T.; Ogama, Y.; Kawamoto, M.; Okazaki, T.; Ayai, N.; Oyama, H.

    2008-08-01

    We report on the direct relationship between output power and the current carrying capability of a squirrel-cage HTS induction/synchronous motor based on experiment. The secondary windings are fabricated by use of so-called DI-BSCCO tapes, and the conventional (normal conducting) stator, three-phase and four-pole, is utilized. The tests are carried out in liquid nitrogen for two kinds of HTS windings, in which the number of HTS rotor bars is varied. It is directly shown that the output power is proportional to the rotor bars' critical current at 77 K. In other words, the torque can be enlarged by increasing the critical current of the HTS rotor bars.

  9. A novel induction motor starting method using superconduction

    International Nuclear Information System (INIS)

    Highlights: • Alternative method for starting up induction motor. • Based on using a high-temperature superconductor. • A prototype of the limiter was constructed with a 2G-YBCO tape. • Prototype was tested with a 55-kW industrial induction motor in a 440-V/60-Hz. • Offers reduced current waveform distortion compared to the soft starter method. - Abstract: In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method

  10. A novel induction motor starting method using superconduction

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F.B.B., E-mail: flaviobarcelos@ifes.edu.br [Ifes – Federal Institute of Espírito Santo, Dept. of Industrial Automation, Serra, ES 29173087 (Brazil); UFES – Federal University of Espírito Santo, Dept. of Electrical Engineering, Vitória, ES (Brazil); Orlando, M.T.D. [UFES – Federal University of Espírito Santo, Dept. of Physics, Vitória, ES (Brazil); Fardin, J.F.; Simonetti, D.S. [UFES – Federal University of Espírito Santo, Dept. of Electrical Engineering, Vitória, ES (Brazil); Baldan, C.A. [EEL/USP – Engineering School from Lorena/University of São Paulo, SP (Brazil)

    2014-12-15

    Highlights: • Alternative method for starting up induction motor. • Based on using a high-temperature superconductor. • A prototype of the limiter was constructed with a 2G-YBCO tape. • Prototype was tested with a 55-kW industrial induction motor in a 440-V/60-Hz. • Offers reduced current waveform distortion compared to the soft starter method. - Abstract: In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method.

  11. Nonlinear Differential Geometry Method and Its Application in Induction Motor Decoupling Control

    Directory of Open Access Journals (Sweden)

    Linyuan Fan

    2016-05-01

    Full Text Available An alternating current induction motor is a nonlinear, multi-variable, and strong-coupled system that is difficult to control. To address this problem, a novel control strategy based on nonlinear differential geometry theory was proposed. First, a five-order affine mathematical model for an alternating current induction motor was provided. Then, the feedback linearization method was used to realize decoupling and full linearization of the system model. Moreover, a general and simplified control law was adopted to facilitate practical applications. Finally, a controller was designed using the pole assignment method. Simulation results show that the proposed method can decouple the system model into two independent subsystems, and that the closed-loop system exhibits good dynamic and static performances. The proposed decoupling control method is useful to reduce the system complexity of an induction motor and to improve its control performance, thereby providing a new and feasible dynamic decoupling control for an alternating current induction motor.

  12. Speed Control of Brushless Dc Motor Using Current Fed Quasi Z-source Inverter with Regeneration Capability

    OpenAIRE

    A. Santhi Mary Antony; Ramya, D.; J. Sangeetha

    2015-01-01

    Current fed Quasi Z-Source Inverters (qZSI) have the advantages of voltage buck-boost capability, improved reliability, reduced passive component ratings, continuous input current, a common dc rail between source and inverter and unique regeneration capability. This current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. Since current fed quasi Z Source Inverter has many advantages it can be employed for...

  13. Alternating and direct current electrochemical studies of a wool wax-based corrosion preventive coating on aluminum alloy 2024

    Energy Technology Data Exchange (ETDEWEB)

    Su, P.C.; Devereux, O.F. [Univ. of Connecticut, Storrs, CT (United States). Dept. of Metallurgy and Materials Engineering

    1998-06-01

    The corrosion behavior of Al 2024-T3 treated with a wool wax (lanolin)-based corrosion preventive coating in aqueous 0.5 M sodium chloride was studied using electrochemical impedance spectroscopy (EIS) and direct current electrode polarization. DC measurements were modeled by three reactions: oxidation of aluminum, reduction of oxygen, and reduction of hydrogen. Alternating current behavior of untreated specimens was modeled using the Randles circuit, and that of inhibited specimens was modeled using parallel resistance-capacitance circuits representing the coating and the charge-transfer process. AC and DC estimates of the polarization resistance of coated specimens were 50 M{Omega}-cm{sup 2} and 32 M{Omega}-cm{sup 2}, respectively. AC and DC values for bare control specimens were of the order of 3 k{Omega}-cm{sup 2} and 15 k{Omega}-cm{sup 2}, respectively. The wool wax coating was found to be a very effective corrosion preventative for this alloy in the aqueous saline environment whether applied to freshly prepared surfaces or to corroded specimens removed from simulated service.

  14. Aneurysm Sac Pressure Measurement with Minimally Invasive Implantable Pressure Sensors: An Alternative to Current Surveillance Regimes after EVAR?

    International Nuclear Information System (INIS)

    Current protocols for surveillance after endovascular repair (EVAR) of abdominal aortic aneurysms are mostly based on costly and time-consuming imaging procedures and aim to detect adverse events such as graft migration, endoleaks or aneurysm sac enlargement. These imaging procedures are either associated with radiation exposure to the patients or may be harmful to the patient due to the use of iodine- or gadolinium-containing contrast agents. Furthermore the advantages of EVAR in the short term might be negated by the necessity for endograft surveillance over years. Thus, alternative modalities for follow-up are being investigated. One of these technologies provides pressure information directly from the aneurysm sac. This noninvasive, telemetric pressure sensing was tested in vitro as well as in first clinical trials and was able to identify successful aneurysm exclusion after EVAR. The telemetric pressure sensors showed a promising efficacy and accuracy in detecting type I and type III endoleaks and will help to clarify the clinical relevance of type II endoleaks. This article provides an overview of the in vitro sensors investigated as well as the first clinical trials and the sensors' potential to change the current endograft surveillance regimes

  15. Two-way shape memory effect and alternating current driving characteristics of a TiNi alloy spring

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiguo; ZU Xiaotao

    2004-01-01

    Two-way shape memory effect (TWSME) was induced into the TiNi shape memory alloys (SMAs) spring by thermomechanical training after annealing treatment, which has promising application in micro-actuating fields. The TWSME spring can contract upon heating and extend upon cooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of 45%. During the training procedure, transformation temperatures and hysteresis were measured by different scanning calorimetry (DSC). The results show that As (reverse transformation start temperature) and Af (revere transformation finish temperature) shift to lower temperature after training. The intervals of Af-As and Ms-Mr (Ms and Mf are the martensite start and finish temperatures, respectively) increase and the heat of transformation decreases after training. The electrothermal driving characteristics of the TWSME springs were also investigated with alternating current density of 3.2-14.7 A/mm2. It is found that the time response and the maximum contraction ratio greatly depend on the magnitude of the electrical current density.

  16. Analysis of Input Currents in «Frequency Converter - Induction Motor» System under Asymmetry of Mains Voltage

    Directory of Open Access Journals (Sweden)

    B. I. Firago

    2006-01-01

    Full Text Available The influence of modem firequency converters with uncontrolled rectifiers on the supply network is investigated in this paper. The developed mathematical model permits us to analyze rectifier input currents with symmetrical and asymmetrical supply networks and in discontinuous operational mode. Results of modeling in case of asymmetrical supply network are shown in the form of mains current curves and current spectrum of one phase.

  17. Evidence for inhibitory effects of flupirtine, a centrally acting analgesic, on delayed rectifier k(+) currents in motor neuron-like cells.

    Science.gov (United States)

    Wu, Sheng-Nan; Hsu, Ming-Chun; Liao, Yu-Kai; Wu, Fang-Tzu; Jong, Yuh-Jyh; Lo, Yi-Ching

    2012-01-01

    Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K(+) currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K(+) current (I(K(DR))) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of I(K(DR)) inactivation rate was about 9.8 μM. Neither linopirdine (10 μM), NMDA (30 μM), nor gabazine (10 μM) reversed Flu-induced changes in I(K(DR)) inactivation. Addition of Flu shifted the inactivation curve of I(K(DR)) to a hyperpolarized potential. Cumulative inactivation for I(K(DR)) was elevated in the presence of this compound. Flu increased the amplitude of M-type K(+) current (I(K(M))) and produced a leftward shift in the activation curve of I(K(M)). In another neuronal cells (NG108-15), Flu reduced I(K(DR)) amplitude and enhanced the inactivation rate of I(K(DR)). The results suggest that Flu acts as an open-channel blocker of delayed-rectifier K(+) channels in motor neurons. Flu-induced block of I(K(DR)) is unlinked to binding to NMDA or GABA receptors and the effects of this agent on K(+) channels are not limited to its action on M-type K(+) channels. PMID:22888361

  18. 一个新的适用于无刷直流电机驱动的单电流传感器技术%A Novel Current Sensor Technique for Brushless DC Motor Drives

    Institute of Scientific and Technical Information of China (English)

    谭徽; 江建中; 汪信尧; 王勇

    2000-01-01

    The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.

  19. Transcranial alternating current stimulation (tACS increases risk taking behavior in the Balloon Analogue Risk Task

    Directory of Open Access Journals (Sweden)

    MichalLavidor

    2012-02-01

    Full Text Available The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC. It has been proposed that in conflict and reward situations, theta-band (4–8 Hz oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere, is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial Alternating Current Stimulation (tACS, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation / RH stimulation / Sham stimulation, with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1mA peak to-peak. During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

  20. Electrical motor/generator drive apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Su, Gui Jia

    2013-02-12

    The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

  1. Alternating current calorimeter for specific heat capacity measurements at temperatures below 10 K and pressures up to 10 GPa.

    Science.gov (United States)

    Umeo, Kazunori

    2016-06-01

    A developed alternating current calorimeter for measuring the absolute value of specific heat C of a very small sample under a pressure up to 10 GPa and low temperature below 10 K is described. A Bridgman anvil cell made of tungsten carbide with a top diameter of 3 mm is used. A hollow at the top prevents expansion of the sample space over the anvil top. Two chip resistors, which act as a thermometer and a heater, are mounted on the outer part of a copper-beryllium gasket with a frying pan-like shape. Thus, the thermometer is not pressurized. In order to isolate the gasket from the anvil thermally, diamond powder with a grain size of 0.25 μm is placed on the anvil top. Two jumps of C at the superconducting transitions of Pb (3.3 mg) and In (5.0 mg) are observed under various pressures up to 9 GPa, as clearly as those at the ambient pressure. PMID:27370464

  2. Enhancing Protein Capture Using a Combination of Nanoyeast Single-Chain Fragment Affinity Reagents and Alternating Current Electrohydrodynamic Forces.

    Science.gov (United States)

    Vaidyanathan, Ramanathan; Rauf, Sakandar; Grewal, Yadveer S; Spadafora, Lauren J; Shiddiky, Muhammad J A; Cangelosi, Gerard A; Trau, Matt

    2015-12-01

    New high-performance detection technologies and more robust protein capture agents can be combined to both rapidly and specifically capture and detect protein biomarkers associated with disease in complex biological samples. Here we demonstrate the use of recently developed recombinant affinity reagents, namely nanoyeast-scFv, in combination with alternating current electrohydrodynamic (ac-EHD)-induced shear forces, to enhance capture performance during protein biomarker analysis. The use of ac-EHD significantly improves fluid transport across the capture domain, resulting in enhanced sensor-target interaction and simultaneous displacement of nonspecific molecules from the electrode surface. We demonstrate this simple proof-of-concept approach for the capture and detection of Entamoeba histolytica antigens from disinfected stool, within a span of 5 min using an ac-EHD microfluidic device. Under an ac-EHD field, antigens were captured on a nanoyeast-scFv immobilized device and subsequently detected using a quantum dot conjugated antibody. This immunosensor specifically detected antigen in disinfected stool with low background noise at concentrations down to 58.8 fM with an interassay reproducibility (%RSD of n = 3) gold electrodes in disinfected stool. We predict this rapid and sensitive approach using these stable affinity reagents may offer a new methodology to detect protein disease biomarkers from biological matrices. PMID:26551436

  3. Alternating current characterization of nano-Pt(II) octaethylporphyrin (PtOEP) thin film as a new organic semiconductor

    Science.gov (United States)

    M, Dongol; M, M. El-Nahass; A, El-Denglawey; A, A. Abuelwafa; T, Soga

    2016-06-01

    Alternating current (AC) conductivity and dielectric properties of thermally evaporated Au/PtOEP/Au thin films are investigated each as a function of temperature (303 K–473 K) and frequency (50 Hz–5 MHz). The frequency dependence of AC conductivity follows the Jonscher universal dynamic law. The AC-activation energies are determined at different frequencies. It is found that the correlated barrier hopping (CBH) model is the dominant conduction mechanism. The variation of the frequency exponent s with temperature is analyzed in terms of the CBH model. Coulombic barrier height W m , hopping distance R ω , and the density of localized states N(E F) are valued at different frequencies. Dielectric constant ε 1(ω,T) and dielectric loss ε 2(ω,T) are discussed in terms of the dielectric polarization process. The dielectric modulus shows the non-Debye relaxation in the material. The extracted relaxation time by using the imaginary part of modulus (M″) is found to follow the Arrhenius law.

  4. In situ measurement of alternating current magnetic susceptibility of Pd-hydrogen system for determination of hydrogen concentration in bulk

    Science.gov (United States)

    Akamaru, Satoshi; Hara, Masanori; Matsuyama, Masao

    2012-07-01

    An alternating current magnetic susceptometer for use as a hydrogen gauge for hydrogen-storage materials was designed and developed. The experimental system can simultaneously measure the hydrogen equilibrium pressure and the magnetic susceptibility of metal hydrides. The background voltage of the susceptometer was stabilized for a long period of time, without any adjustments, by attaching an efficient compensation circuit. The performance of the susceptometer at a static hydrogen concentration was demonstrated by measuring the magnetic susceptibility of a Pd-hydrogen system under equilibrium conditions. The in situ measurement of the magnetic susceptibility of Pd during hydrogen absorption was carried out using the susceptometer. Since the in situ magnetic susceptibility obtained at a lower initial hydrogen pressure agreed with the magnetic susceptibility measured at a static hydrogen concentration, the susceptometer could be used to determine the hydrogen concentration in Pd in situ. At a higher initial hydrogen pressure, enhancement of the magnetic susceptibility was observed at the beginning of hydrogen absorption because the magnetic moments induced by the large temporary strain generated in the Pd affected the magnetic susceptibility.

  5. Alternating current calorimeter for specific heat capacity measurements at temperatures below 10 K and pressures up to 10 GPa

    Science.gov (United States)

    Umeo, Kazunori

    2016-06-01

    A developed alternating current calorimeter for measuring the absolute value of specific heat C of a very small sample under a pressure up to 10 GPa and low temperature below 10 K is described. A Bridgman anvil cell made of tungsten carbide with a top diameter of 3 mm is used. A hollow at the top prevents expansion of the sample space over the anvil top. Two chip resistors, which act as a thermometer and a heater, are mounted on the outer part of a copper-beryllium gasket with a frying pan-like shape. Thus, the thermometer is not pressurized. In order to isolate the gasket from the anvil thermally, diamond powder with a grain size of 0.25 μm is placed on the anvil top. Two jumps of C at the superconducting transitions of Pb (3.3 mg) and In (5.0 mg) are observed under various pressures up to 9 GPa, as clearly as those at the ambient pressure.

  6. Online Monitoring of Induction Motors

    Energy Technology Data Exchange (ETDEWEB)

    McJunkin, Timothy R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lybeck, Nancy Jean [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-01-01

    The online monitoring of active components project, under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program, researched diagnostic and prognostic models for alternating current induction motors (IM). Idaho National Laboratory (INL) worked with the Electric Power Research Institute (EPRI) to augment and revise the fault signatures previously implemented in the Asset Fault Signature Database of EPRI’s Fleet Wide Prognostic and Health Management (FW PHM) Suite software. Induction Motor diagnostic models were researched using the experimental data collected by Idaho State University. Prognostic models were explored in the set of literature and through a limited experiment with 40HP to seek the Remaining Useful Life Database of the FW PHM Suite.

  7. Slow-oscillatory transcranial direct current stimulation can induce bidirectional shifts in motor cortical excitability in awake humans

    DEFF Research Database (Denmark)

    Groppa, S; Bergmann, T O; Siems, C;

    2010-01-01

    (MEPs) confirmed previous work showing that anodal c-tDCS at an intensity of 0.75 mA (maximal current density 0.0625 mA/cm2) enhanced corticospinal excitability, while cathodal c-tDCS at 0.75 mA reduced it. The polarity-specific shifts in excitability persisted for at least 20 min after c-tDCS. Using a...... peak current intensity of 0.75 mA, neither anodal nor cathodal so-tDCS had consistent effects on corticospinal excitability. Experiment 2. In a separate group of ten individuals, peak current intensity of so-tDCS was raised to 1.5 mA (maximal current density 0.125 mA/cm2) to match the total amount of...... current applied with so-tDCS to the amount of current that had been applied with c-tDCS at 0.75 mA in Experiment 1. At peak intensity of 1.5 mA, anodal and cathodal so-tDCS produced bidirectional changes in corticospinal excitability comparable to the after effects that had been observed after c-tDCS at 0...

  8. Use of functional near-infrared spectroscopy to evaluate the effects of anodal transcranial direct current stimulation on brain connectivity in motor-related cortex

    Science.gov (United States)

    Yan, Jiaqing; Wei, Yun; Wang, Yinghua; Xu, Gang; Li, Zheng; Li, Xiaoli

    2015-04-01

    Transcranial direct current stimulation (tDCS) is a noninvasive, safe and convenient neuro-modulatory technique in neurological rehabilitation, treatment, and other aspects of brain disorders. However, evaluating the effects of tDCS is still difficult. We aimed to evaluate the effects of tDCS using hemodynamic changes using functional near-infrared spectroscopy (fNIRS). Five healthy participants were employed and anodal tDCS was applied to the left motor-related cortex, with cathodes positioned on the right dorsolateral supraorbital area. fNIRS data were collected from the right motor-related area at the same time. Functional connectivity (FC) between intracortical regions was calculated between fNIRS channels using a minimum variance distortion-less response magnitude squared coherence (MVDR-MSC) method. The levels of Oxy-HbO change and the FC between channels during the prestimulation, stimulation, and poststimulation stages were compared. Results showed no significant level difference, but the FC measured by MVDR-MSC significantly decreased during tDCS compared with pre-tDCS and post-tDCS, although the FC difference between pre-tDCS and post-tDCS was not significant. We conclude that coherence calculated from resting state fNIRS may be a useful tool for evaluating the effects of anodal tDCS and optimizing parameters for tDCS application.

  9. The mathematical model of the motor drive current based on considerable measure%可观测量的电动机驱动电流建模

    Institute of Scientific and Technical Information of China (English)

    黄飞超; 陈明明; 杨戍

    2012-01-01

    检验汽车行车制动器设计的优劣,需要得到电动机驱动电流与时间之间的精确关系。因为制动器性能的复杂性,驱动电流与时间之间的精确关系很难得到。基于模拟实验台,由能量等效转化的方法,将能量转化为可观测的转速以及对于转动物体来说恒定不变的转动惯量,建立了电动机驱动电流依赖于可观测量的数学模型。%In order to test the merits of the design on brakes, the precise relationship between the motor drive current and time is necessary. Because of the complexity of the Braking performance, it' s too difficult to get the precise relationship. On the basis of Energy Equivalent Conversion, this essay is to get the mathematical model based on the quantities of the motor, such as rotate speed and rotary inertia which is measurable or constant.

  10. Industrial motor repair in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Schueler, V.; Leistner, P.; Douglass, J.

    1994-09-01

    This report characterizes the motor repair industry in the United States; summarizes current motor repair and testing practice; and identifies barriers to energy motor repair practice and recommends strategies for overcoming those barriers.

  11. Advanced Motors

    Energy Technology Data Exchange (ETDEWEB)

    Knoth, Edward A.; Chelluri, Bhanumathi; Schumaker, Edward J.

    2012-12-14

    Project Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, “Motors and Generators for the 21st Century”. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to

  12. Investigation of Line Current Harmonics in Cascaded Multi-level Inverter Based Induction Motor Drive and an Adaptive On-line Selective Current Harmonic Elimination Algorithm

    Directory of Open Access Journals (Sweden)

    P. Avirajamanjula

    2015-03-01

    Full Text Available Multilevel Inverters (MLIs have drawn increasing attention in numerous applications, especially in drives, distributed energy resources area, utility etc. MLIs have the ability to synthesize a near sinusoidal output voltage wave with minimal Total Harmonic Distortion (THD in low frequency switching. Even though they offer lower THD, the presence of lower order harmonics is objectionable and harmonics elimination in Multilevel Inverters (MLIs has been receiving immense attention for the past few decades. Existing Selective Harmonic Elimination (SHE techniques can eliminate the objectionable lower order voltage harmonics with low switching frequency by solving the Fourier non-linear transcendental equations of the output voltage. The line current harmonics has a direct role to play on the magneto-motive force and results in increase of mismatching of air-gap permeance, vibrations, acoustic noise etc. This study proposes Normalized Least Mean Squares (NLMS algorithm based scheme to eliminate the selected dominant harmonics in load current using only the knowledge of the frequencies to be eliminated. The algorithm is simulated using MATLAB/SIMULINK tool for a three-phase VSI to eliminate the fifth and seventh harmonics. The informative simulation results verify the validity and effectiveness of the proposed algorithm. The system performance is analyzed based on the simulation results considering Total Harmonic Distortion (THD, magnitude of eliminated harmonics and frequency spectrum.

  13. Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation.

    Science.gov (United States)

    Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

    2015-01-01

    Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual's memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity. PMID:26005411

  14. Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation

    Directory of Open Access Journals (Sweden)

    Johannes Vosskuhl

    2015-05-01

    Full Text Available Working memory (WM and short-term memory (STM supposedly rely on the phase-amplitude coupling of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS. To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N=33 were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG was measured before stimulation and analyzed with regard to the properties of phase-amplitude coupling between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

  15. Parameters identification of a permanent magnet DC motor

    Energy Technology Data Exchange (ETDEWEB)

    Salah, M. [Univ. College of Applied Science, Gaza, Palestine (Israel); Abdelati, M. [Islamic Univ. of Gaza, Gaza, Palestine (Israel)

    2010-03-09

    Due to precise, wide, simple, and continuous control characteristics, direct current (DC) motors have been commonly employed in many industrial applications such as electric vehicles, steel rolling mills, electric cranes, and robotic manipulators. Because of their lower cost and ease of controller implementation, DC motors are preferred over alternating current (AC) motors. System identification of DC motors is of great importance in control problems. Accurate mathematical models and their parameters are necessary when designing controllers. This paper addressed driver circuits and parameters identification of a permanent magnet DC motor. An experimental measurement of armature voltage, armature current and rotor speed were performed using a data acquisition module in order to identify the parameters of the motor. DAQ toolbox and Simulink in MATLAB were used to obtain test signals and perform analysis based on the nonlinear least square method. The extracted motor parameters produced consistent simulation results with experimental data. It was concluded that the proposed approach is simple, fast and accurate. 16 refs., 4 tabs., 9 figs.

  16. Modelling of the steady state thermal behaviour of a permanent magnet direct current motor with commutator. 3D finite elements study

    Science.gov (United States)

    Bernard, R.; Glises, R.; Chamagne, D.; Cuchet, D.; Kauffmann, J. M.

    1999-08-01

    The aim of this work concerns the development and the validation of a thermal steady state model applied to a permanent magnet direct current motor with commutator. The rated power of the machine is 120 W. Design has been realized thanks to the thermal modulus of the computation software with the finite element method Flux3D. It is shown in this work how it is possible to use only the heat equation to simulate the thermal behaviour of the motor. It implies calculating of new fluid conductivities (considering also all thermal modes) by comparison of calculated and experimental temperatures. To realize these 3D modelizations, it is necessary to know and to locate all the losses of the motor which are considered as thermal sources. The experimental temperatures are given by 40 chromel-alumel thermocouples of 100 μm diameter located in the rotor and the stator of the machine. Numerical computations use Dirichlet boundary layer conditions given by an IR camera. Ce travail concerne le développement et la validation d'un modèle de simulation du comportement thermique tridimensionnel en régime permanent d'un moteur électrique de 120 watt à courant continu, à aimants permanents et à collecteur. Le logiciel est développé à partir du code de calculs par éléments finis Flux3D. L'équation de la chaleur modélise l'ensemble des transferts thermiques du moteur. Cela nécessite de recaler certains paramètres fluides par comparaison des températures simulées et expérimentales. Une séparation détaillée des différentes pertes est nécessaire pour obtenir une bonne précision finale. Un banc d'essais thermiques permet d'obtenir à l'aide de 40 thermocouples (chromel-alumel de 100 μm de diamètre) les températures au stator et au rotor. Une caméra thermographique infrarouge donne les conditions aux limites de Dirichlet nécessaires à la modélisation.

  17. A versatile stepping motor controller for systems with many motors

    International Nuclear Information System (INIS)

    A versatile system for controlling beamlines or complex experimental setups is described. The system as currently configured can control up to 32 motors, with all motors capable of full speed operation concurrently. There are 2 limit switch inputs for each motor, and a further input to accept a reference position marker. The motors can be controlled via a front panel keyboard with display, or by a host computer over an IEEE-488 interface. Both methods can be used together if required. There is an ''emergency stop'' key on the front panel keyboard to stop the motion of all motors without losing track of the motors' position. 3 refs., 4 figs., 1 tab

  18. Sensorless rotor-position estimating at standstill of cylindrical brushless DC motors using opened phase voltage change caused by eddy currents; Uzu denryu ni yoru kaiho soden`atsu henka wo riyoshita entogata brushless DC motor no sensorless teishi ichi suiteiho

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, M.; Doki, S.; Okuma, S. [Nagoya University, Nagoya (Japan); Yamaguchi, H. [The Aichi Electric Co. Ltd., Aichi (Japan)

    1997-09-20

    A rotor position estimation of a cylindrical brushless dc motor at a standstill has been difficult. Therefore, a torque control of a motor has been difficult at starting of the motor, and the realization of the position estimation at a standstill has been desired. This paper proposes a simple processing of a rotor that non-magnetic materials are pasted on a rotor surface. This processing generates an eddy current on non-magnetic materials and causes an opened phase voltage change according to a rotor position. The experimental results used a microcomputer show that it is possible to estimate a rotor position of the cylindrical motor despite of a standstill by using the opened phase voltage change. 10 refs., 15 figs.

  19. Investigation of parameters of the three phase high-voltage alternating current plasma generator with power up to 100 kW working on steam

    Science.gov (United States)

    Rutberg, Ph G.; Lukyanov, S. A.; Kiselev, A. A.; Kuschev, S. A.; Nakonechny, Gh V.; Nikonov, A. V.; Popov, S. D.; Serba, E. O.; Spodobin, V. A.; Surov, A. V.

    2011-01-01

    The paper presents the results of experimental investigation of parameters of the three-phase high voltage alternating current plasma generator with power up to 100 kW operating on steam with gas protection of the electrodes. Researches were carried out over a range of arc current from 25 to 50 A and range of steam consumption of 3-5 g/s. Current-voltage and volt consumable characteristics, operation oscillograms and dependence of power versus the flow rate of steam and protective gas are presented.

  20. Alternative splicing at C terminus of Ca(V)1.4 calcium channel modulates calcium-dependent inactivation, activation potential, and current density.

    Science.gov (United States)

    Tan, Gregory Ming Yeong; Yu, Dejie; Wang, Juejin; Soong, Tuck Wah

    2012-01-01

    The Ca(V)1.4 voltage-gated calcium channel is predominantly expressed in the retina, and mutations to this channel have been associated with human congenital stationary night blindness type-2. The L-type Ca(V)1.4 channel displays distinct properties such as absence of calcium-dependent inactivation (CDI) and slow voltage-dependent inactivation (VDI) due to the presence of an autoinhibitory domain (inhibitor of CDI) in the distal C terminus. We hypothesized that native Ca(V)1.4 is subjected to extensive alternative splicing, much like the other voltage-gated calcium channels, and employed the transcript scanning method to identify alternatively spliced exons within the Ca(V)1.4 transcripts isolated from the human retina. In total, we identified 19 alternative splice variations, of which 16 variations have not been previously reported. Characterization of the C terminus alternatively spliced exons using whole-cell patch clamp electrophysiology revealed a splice variant that exhibits robust CDI. This splice variant arose from the splicing of a novel alternate exon (43*) that can be found in 13.6% of the full-length transcripts screened. Inclusion of exon 43* inserts a stop codon that truncates half the C terminus. The Ca(V)1.4 43* channel exhibited robust CDI, a larger current density, a hyperpolarized shift in activation potential by ∼10 mV, and a slower VDI. Through deletional experiments, we showed that the inhibitor of CDI was responsible for modulating channel activation and VDI, in addition to CDI. Calcium currents in the photoreceptors were observed to exhibit CDI and are more negatively activated as compared with currents elicited from heterologously expressed full-length Ca(V)1.4. Naturally occurring alternative splice variants may in part contribute to the properties of the native Ca(V)1.4 channels. PMID:22069316

  1. Load-Responsive Motor Controller

    Science.gov (United States)

    Edge, T. M.

    1982-01-01

    New circuit controls voltage applied to a three-phase induction motor in response to magnitude of current, so as to reduce power consumption when the motor is idling or operating at less than full load. Control circuit decreases rms applied voltage to match decreases in motor load over entire torque range. This considerably decreases power consumption in motors operating at a fraction of their rated torques.

  2. Cryogenic Electric Motor Tested

    Science.gov (United States)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  3. Transcranial Direct Current Stimulation over the Medial Prefrontal Cortex and Left Primary Motor Cortex (mPFC-lPMC) Affects Subjective Beauty but Not Ugliness.

    Science.gov (United States)

    Nakamura, Koyo; Kawabata, Hideaki

    2015-01-01

    Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC) and the left primary motor cortex (lPMC) correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS) to examine whether non-invasive brain stimulation modulates two types of esthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions. PMID:26696865

  4. Transcranial direct current stimulation over the medial prefrontal cortex and left primary motor cortex (mPFC-lPMC affects subjective beauty but not ugliness

    Directory of Open Access Journals (Sweden)

    Koyo eNakamura

    2015-12-01

    Full Text Available Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC and the left primary motor cortex (lPMC correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS to examine whether noninvasive brain stimulation modulates two types of aesthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions.

  5. Effects of left primary motor and dorsolateral prefrontal cortex transcranial direct current stimulation on laser-evoked potentials in migraine patients and normal subjects.

    Science.gov (United States)

    Vecchio, Eleonora; Ricci, Katia; Montemurno, Anna; Delussi, Marianna; Invitto, Sara; de Tommaso, Marina

    2016-07-28

    Migraine is characterized by an altered cortical excitability. Because transcranial direct current stimulation (tDCS) can change brain activity noninvasively, it is possible to hypothesize its efficacy in modulating pain in migraine. In this study, we compared the effects of tDCS of the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) both on subjective pain and on evoked responses induced by laser stimulation (LEPs). Thirty-two patients and sixteen controls were randomized to receive sham stimulation and real tDCS with the anode centered over M1 or DLPFC. Laser Evoked potentials were recorded in basal, sham and tDCS conditions. We did not find significant acute changes in LEPs parameters and pain perception among subjects who received tDCS of both M1 and DLPFC. After DLPFC tDCS, we observed a significant increase of N2-P2 component habituation in migraine patients while M1 stimulation reduced it. These findings may suggest a modulation of abnormal pain processing induced by DLPFC and M1 anodal tDCS and outline the need for future investigations exploring the possible neuronal plasticity changes supporting the clinical effect on migraine. PMID:27208831

  6. Motor variability in occupational health and performance.

    Science.gov (United States)

    Srinivasan, Divya; Mathiassen, Svend Erik

    2012-12-01

    Several recent reviews have reported that 'repetitive movements' constitute a risk factor for occupational musculoskeletal disorders in the neck, shoulder and arm regions. More variation in biomechanical exposure is often suggested as an effective intervention in such settings. Since increasing variation using extrinsic methods like job rotation may not always be possible in an industrial context, the intrinsic variability of the motor system may offer an alternative opportunity to increase variation. Motor variability refers to the natural variation in postures, movements and muscle activity observed to different extents in all tasks. The current review discusses research appearing in motor control, sports sciences and occupational biomechanics literature to answer whether motor variability is important to consider in an occupational context, and if yes, whether it can be manipulated by training the worker or changing the working conditions so as to increase biomechanical variation without jeopardizing production. The review concludes that motor variability is, indeed, a relevant issue in occupational health and performance and suggests a number of key issues for further research. PMID:22954427

  7. Palm oil production in Peruvian Amazon Basin. A case study of current effects and emerging localized alternatives in Loreto district

    OpenAIRE

    Jensen, Charlotte Bratberget

    2015-01-01

    An analysis of palm oil production in the Peruvian Amazon basin was carried out in a systemic way, as part of a whole, with its complexities. With an agroecological perspective, the social, ecological and economic effects of this production are discussed. Additionally, alternatives that could better fulfil the necessities of farmers were explored. The oil palm, Elaeis guineensis, originally from West Africa, is a common plant in an enormous industry that is extensive in South East Asia, ma...

  8. A new multi-motor drive system based on two-stage direct power converter

    OpenAIRE

    Kumar, Dinesh

    2011-01-01

    The two-stage AC to AC direct power converter is an alternative matrix converter topology, which offers the benefits of sinusoidal input currents and output voltages, bidirectional power flow and controllable input power factor. The absence of any energy storage devices, such as electrolytic capacitors, has increased the potential lifetime of the converter. In this research work, a new multi-motor drive system based on a two-stage direct power converter has been proposed, with two motors c...

  9. Efficiency Improvement of a High Dynamic BLDC Linear Motor by Multiphase Control

    OpenAIRE

    Lemmens, Joris; Vanvlasselaer, Kris; Mulier, Kristof; Goossens, Stijn; Symens, Wim; Driesen, Johan

    2013-01-01

    This paper proposes a multiphase control strategy for a high dynamic brushless DC linear motor as an alternative for conventional three-phase field-oriented control. Analysis of the magnetic field waveforms shows that three-phase control is not optimal for the 6-slot 7-pole motor topology. Therefore, a multiphase control strategy is elaborated which injects currents proportional to the electromotive force into each of the nine stator coil groups. This results in a maximal alignment force ...

  10. High Voltage Resistive Divider Based on Cast Microwire in Glass Insulation on 6–24 kV Alternating Current of Commercial Frequency.

    Directory of Open Access Journals (Sweden)

    Juravleov A.

    2008-12-01

    Full Text Available It is presented the analysis and description of the construction of the high voltage resistive divider on the base of cast microwire in glass insulation on 6–24 kV alternating current of commercial frequency. It is presented the procedure of compensation of frequency error during the process of fabrication of divides and results of tests of the sample model of the divider as well.

  11. Alternatives and selection of an electrical motor for the autonomous hybrid drive system; Alternativen und Auswahl eines Elektromotors fuer den Autarken Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Krasser, B.; Lorenzen, H.W.; Schmid, M.

    1994-12-31

    Equipping a vehicle with a hybrid drive system always involves additional components to be installed. These components will have to be specifically light of weight with a view to total vehicle weight increase. In the electrical motor, weight savings may be achieved by an appropriate selection of motor concept and speed. The weight of electronic parts is largely determined by the weight of the associated heat dissipation systems. The different drive trains will be studied for their efficiency and operating properties in various test cycles on test stand which is being set up. This test rig will have a high-precision output analyzer which will be accurate if samples are static-converter-fed. Computer simulations will be used for optimization. (orig./HW) [Deutsch] Die Ausruestung eines Fahrzeugs mit einem Hybridantrieb bedingt immer zusaetzliche Komponenten. Diese Komponenten muessen im Hinblick auf eine moeglichst geringe Zunahme des Gesamtgewichts besonders leicht sein. Die Gewichtsreduzierung beim Elektromotor laesst sich durch die Wahl des Motorkonzepts und der Drehzahl beeinflussen. Bei der Leistungselektronik wird der groesste Anteil des Gewichts durch die Einrichtungen zur Waemeabfuhr verursacht. Die verschiedenen Antriebsstraenge sollen auf einem im Aufbau befindlichen Pruefstand hinsichtlich Wirkungsgrad und Betriebseigenschaften bei unterschiedlichen Testzyklen untersucht werden. Am Pruefstand wird ein hochgenauer Leistungsanalysator eingesetzt, der auch bei Stromrichterspeisung der Prueflinge praezise arbeitet. Als Hilfe zur Optimierung werden Computersimulationen ausgefuehrt. (orig./HW)

  12. Biomolecular motors

    Directory of Open Access Journals (Sweden)

    Henry Hess

    2005-12-01

    Here, we give a brief introduction to molecular motors, with an emphasis on motor proteins, describe the challenges in interfacing these bionanomachines with an artificial environment, and provide examples of emerging applications.

  13. Coordinated Switching of Bacterial Flagellar Motors: Evidence for Direct Motor-Motor Coupling?

    Science.gov (United States)

    Hu, Bo; Tu, Yuhai

    2013-04-01

    The swimming of Escherichia coli is powered by its multiple flagellar motors. Each motor spins either clockwise or counterclockwise, under the control of an intracellular regulator, CheY-P. There can be two mechanisms (extrinsic and intrinsic) to coordinate the switching of bacterial motors. The extrinsic one arises from the fact that different motors in the same cell sense a common input (CheY-P) which fluctuates near the motors’ response threshold. An alternative, intrinsic mechanism is direct motor-motor coupling which makes synchronized switching energetically favorable. Here, we develop simple models for both mechanisms and uncover their different hallmarks. A quantitative comparison to the recent experiments suggests that the direct coupling mechanism may be accountable for the observed sharp correlation between motors in a single Escherichia coli. Possible origins of this coupling (e.g., hydrodynamic interaction) are discussed.

  14. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kajikawa, K., E-mail: kajikawa@sc.kyushu-u.ac.j [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Funaki, K. [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Shikimachi, K.; Hirano, N.; Nagaya, S. [Chubu Electric Power Co., Inc., 20-1 Kitasekiyama, Ohdaka-cho, Midori-ku, Nagoya 459-8522 (Japan)

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  15. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Science.gov (United States)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  16. Organizing motor imageries.

    Science.gov (United States)

    Hanakawa, Takashi

    2016-03-01

    Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980

  17. 基于DSP控制的纯电动汽车无刷直流电动机%Brushless Direct Current Motor Based on DSP Control on Pure Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    吴敏

    2011-01-01

    无刷直流电动机是一种高性能的电动机,它具有结构简单、运行可靠、维护方便、运行效率高、无励磁损耗、运行成本低和调速性能好等优点,因此,它在电动汽车上的应用与日俱增.对无刷直流电动机控制的优化是人们一直期待解决的问题。文章设计了利用TMS320LF2407DSP控制器构成的无刷直流电动机的无位置传感器控制的系统硬件和系统软件,实现了对无位置传感器无刷直流电动机的优化控制,试验证明了该方法的正确性和有效性。%Brushless direct current motor is a type of motor with high performance and many advantages, including simple structure, reliable operation, convenient maintenance, high efficiency, non-excitation loss, low cost and good performance of speed governing. Therefore, its application on electric vehicles has increased. People have been looking forward to the solution to the optimization of the control of brushless direct current motor. This paper designs the eontrolling system's hardware and software for no-position sensor on the brushless current motor with the structure of TMS320LF2407 DSP controller, which optimized the brushless current motor with no-position sensor. The test also proves the correctness and effectiveness of this method.

  18. The effects of anodal transcranial direct current stimulation and patterned electrical stimulation on spinal inhibitory interneurons and motor function in patients with spinal cord injury.

    Science.gov (United States)

    Yamaguchi, Tomofumi; Fujiwara, Toshiyuki; Tsai, Yun-An; Tang, Shuen-Chang; Kawakami, Michiyuki; Mizuno, Katsuhiro; Kodama, Mitsuhiko; Masakado, Yoshihisa; Liu, Meigen

    2016-06-01

    Supraspinal excitability and sensory input may play an important role for the modulation of spinal inhibitory interneurons and functional recovery among patients with incomplete spinal cord injury (SCI). Here, we investigated the effects of anodal transcranial direct current stimulation (tDCS) combined with patterned electrical stimulation (PES) on spinal inhibitory interneurons in patients with chronic incomplete SCI and in healthy individuals. Eleven patients with incomplete SCI and ten healthy adults participated in a single-masked, sham-controlled crossover study. PES involved stimulating the common peroneal nerve with a train of ten 100 Hz pulses every 2 s for 20 min. Anodal tDCS (1 mA) was simultaneously applied to the primary motor cortex that controls the tibialis anterior muscle. We measured reciprocal inhibition and presynaptic inhibition of a soleus H-reflex by stimulating the common peroneal nerve prior to tibial nerve stimulation, which elicits the H-reflex. The inhibition was assessed before, immediately after, 10 min after and 20 min after the stimulation. Compared with baseline, simultaneous application of anodal tDCS with PES significantly increased changes in disynaptic reciprocal inhibition and long-latency presynaptic inhibition in both healthy and SCI groups for at least 20 min after the stimulation (all, p < 0.001). In patients with incomplete SCI, anodal tDCS with PES significantly increased the number of ankle movements in 10 s at 20 min after the stimulation (p = 0.004). In conclusion, anodal tDCS combined with PES could induce spinal plasticity and improve ankle movement in patients with incomplete SCI. PMID:26790423

  19. A Study of Second-Year Engineering Students' Alternative Conceptions about Electric Potential, Current Intensity and Ohm's Law

    Science.gov (United States)

    Periago, M. Cristina; Bohigas, Xavier

    2005-01-01

    The aim of this research was to evaluate and analyse second-year industrial engineering and chemical engineering students prior knowledge of conceptual aspects of "circuit theory". Specifically, we focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between them as expressed by Ohm's law.…

  20. Bearing Fault Detection in Induction Motor-Gearbox Drivetrain

    International Nuclear Information System (INIS)

    The main contribution in the hereby presented paper is to investigate the fault detection capability of a motor current signature analysis by expanding its scope to include the gearbox, and not only the induction motor. Detecting bearing faults outside the induction motor through the stator current analysis represents an interesting alternative to traditional vibration analysis. Bearing faults cause changes in the stator current spectrum that can be used for fault diagnosis purposes. A time-domain simulation of the drivetrain model is developed. The drivetrain system consists of a loaded single stage gearbox driven by a line-fed induction motor. Three typical bearing faults in the gearbox are addressed, i.e. defects in the outer raceway, the inner raceway, and the rolling element. The interaction with the fault is modelled by means of kinematical and mechanical relations. The fault region is modelled in order to achieve gradual loss and gain of contact. A bearing fault generates an additional torque component that varies at the specific bearing defect frequency. The presented dynamic electromagnetic dq-model of an induction motor is adjusted for diagnostic purpose and considers such torque variations. The bearing fault is detected as a phase modulation of the stator current sine wave at the expected bearing defect frequency.

  1. Symmetric Brownian motor

    OpenAIRE

    Gomez-Marin, A.; Sancho, J. M.

    2004-01-01

    In this paper we present a model of a symmetric Brownian motor (SBM) which changes the sign of its velocity when the temperature gradient is inverted. The velocity, external work and efficiency are studied as a function of the temperatures of the baths and other relevant parameters. The motor shows a current reversal when another parameter (a phase shift) is varied. Analytical predictions and results from numerical simulations are performed and agree very well. Generic properties of this type...

  2. Contributions to the Transient Study of an Electric Motor with Shorted Moving Coil

    Directory of Open Access Journals (Sweden)

    Georgescu Daniel

    2014-09-01

    Full Text Available In this article is studied the transient regime of an electric motor with a shorted moving coil, into alternating current supplied. The authors present their contributions related to the conceiving, achieving and testing of experimental stands of an electric motor with a shorted moving coil and to the identification of the mathematical model, indexical function parameters and the coefficients of the mathematical equation of this engine. Finally, the authors' conclusions are presented on the results of experimental studies and moving coil motor behavior in transient regime.

  3. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten;

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current...... and the voltage over the cable close to 90 degrees. This has the effect that the loss cannot be derived directly using most commercial lock-in amplifiers due to their limited absolute accuracy. However, by using two lock-in amplifiers and an appropriate correction scheme the high relative accuracy of...... such lock-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce...

  4. Charging unit for magnetic system of the JINR collective accelerator power supply on the base of alternating current thyristor converter

    International Nuclear Information System (INIS)

    The described charging unit of the capacity store for magnetic system of the JINR collective accelerator is intended for recharging capacitor battery energy loss value in a discharge circuit for the time not exceeding 10 ms. The developed system of automatic voltage control (AVC) for the charging unit ensures operating frequency up to 20-40 Hz, and permits to realize voltage stabilization of the capacitor battery. The three-phase thyristor converter at the inlet of the step-up trasformer of the charging unit controllable by means of the central data handing processing unit GZ 800 (development and fabrication of the GDR) is used. The experimentally measured summarized constant of time of the systems with AVC is 5-8 ms, maximum voltage at the battery of the 100 μF capacity at the frequency of 20 Hz-17.5 kV. The average magnitude of the charge current in the given regime has attained 7A. The charging unit working ability at the frequency of 20 Hz and the 5 kA discharge current has been verified

  5. Enhancing liquid-liquid and solid-liquid phase separation by integrating alternating current electrocoagulators with processing and wastewater control systems

    International Nuclear Information System (INIS)

    Coal, pigments, pharmaceutical solids, ceramics, carbon, clays, metallic powders and ores are among the categorical groups of products which are wasted as suspended solids in aqueous-based wash solutions. Phase separation and recovery of these solids by conventional dewatering systems is costly and relatively inefficient. Alternating current can be used to neutralize the electrical charge on fine and ultra-fine particles in aqueous suspensions, and facilitate agglomeration and settling of these particulates without using chemicals while improving recovery efficiencies. This paper provides an overview of the technology and discusses applications and benefits in the areas of in-plant processing, industrial wastewater treatment, site remediation and water purification

  6. Motor neglect.

    OpenAIRE

    Laplane, D.; Degos, J D

    1983-01-01

    Motor neglect is characterised by an underutilisation of one side, without defects of strength, reflexes or sensibility. Twenty cases of frontal, parietal and thalamic lesions causing motor neglect, but all without sensory neglect, are reported. It is proposed that the cerebral structures involved in motor neglect are the same as those for sensory neglect and for the preparation of movement. As in sensory neglect, the multiplicity of the structures concerned suggests that this interconnection...

  7. Motor syndromes.

    Science.gov (United States)

    Corea, Francesco; Micheli, Sara

    2012-01-01

    Motor disturbances alone or associated with other focal deficits are the most common symptoms suggesting a neurovascular event. An appropriate clinical assessment of these signs and symptoms may help physicians to better diagnose and to both better treat and predict outcome. In this paper the main clinical features of motor deficit are described together with other motor-related events such as ataxia and movement disturbances. PMID:22377850

  8. Motor Control: The Heart of Kinesiology

    Science.gov (United States)

    Latash, Mark L.

    2008-01-01

    This brief review presents the subjective view of the author on the history of motor control and its current state among the subdisciplines of kinesiology. It summarizes the current controversies and challenges in motor control and emphasizes the necessity for an adequate set of notions that would make motor control (and kinesiology) a science.…

  9. Alternating current losses in stacked Bi2Sr2Ca2Cu3O10/Ag tapes in perpendicular magnetic fields

    International Nuclear Information System (INIS)

    Alternating current losses in stacks of powder-in-tube-processed Bi2Sr2Ca2Cu3O10/Ag tapes were measured in perpendicular magnetic fields and compared with calculated hysteresis losses based on the critical-state model. Four main factors had to be taken into account for the calculations of the losses: (1) the inclusion of the area of the Ag sheath in determining the critical-current densities of the stacks, (2) the zero-applied-field critical currents Ic(perpendicularsign)(0) with truly perpendicular fields only, not the standard self-field critical current IcS(0), and (3) the field-dependent critical current Ic(H), e.g., the Kim's model, and (4) the subtraction of the frequency-dependent losses at very high fields. With these considerations, the agreement between the calculated and the measured values of the losses is excellent for fields beyond the full-penetration fields. However, these factors did not totally account for the low-field losses. (c) 2000 American Institute of Physics

  10. Harmonic flux penetration of superconductors in low-frequency, high-amplitude, alternating-current magnetic fields

    CERN Document Server

    Ramsbottom, H D

    1997-01-01

    A critical-state model has been used to calculate the magnetic response of a superconducting sample to an applied a.c. magnetic field. The analysis has been performed for both a cylindrical and a slab geometry and evaluated up to the tenth harmonic. It is shown that standard expressions derived using the critical-state model which relate the critical current density to the d.c. magnetic moment can be used in a.c. measurements to within an accuracy of approx 4% by replacing the term for the d.c. magnetic moment by sq root 2m sub r sub m sub s (min), where m sub r sub m sub s (min) is the minimum lossless rms magnetic moment; the apparent penetration of the field beyond the centre of the sample (i.e. an overshoot) found in flux penetration measurements is an artifact of the analysis and cannot be used as direct evidence for granularity. Flux penetration measurements on non-granular NbTi from 4.2 K up to T sub c in magnetic fields up to 10 T are presented which provide good agreement with calculations. (author)

  11. Torque and Current Ripple Analytical Investigation in Space-Vector PWM Inverter Fed Induction Motor Drive under DC-Bus Voltage Pulsation

    Czech Academy of Sciences Publication Activity Database

    Klíma, J.; Chomát, Miroslav; Schreier, Luděk

    Piscataway: IEEE, 2008, s. 1-6. ISBN 978-1-4244-1736-0. [International Conference on Electrical Machines - ICEM 2008 /18./. Vilamoura (PT), 06.09.2008-09.09.2008] Institutional research plan: CEZ:AV0Z20570509 Keywords : DC-link voltage pulsations * torque ripple * nduction motor Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering www.apdee.org

  12. Current levels and composition profiles of PBDEs and alternative flame retardants in surface sediments from the Pearl River Delta, southern China: Comparison with historical data

    International Nuclear Information System (INIS)

    Polybrominated diphenyl ethers (PBDEs) and alternative flame retardants were measured in surface sediments collected during 2009–2010 from the Pearl River Delta, southern China (a large manufacturing base for electronics/electrical products), to evaluate the influence of China's RoHS directive (adopted in 2006) on their environmental occurrence. The concentrations in sediments from different water systems ranged from 3.67 to 2520 ng/g (average of 17.1–588 ng/g) for PBDEs and from 0.22 to 5270 ng/g (average of 11.3–454 ng/g) for the alternative retardants. Although the PBDE levels have decreased significantly compared with those in sediments collected in 2002 in this region, the levels of alternative decabromodiphenyl ethane (DBDPE) have exceeded those of BDE209 (two predominant halogenated flame retardants (HFRs) in China) in the majority of sediments. This finding suggests a different contaminant pattern of HFRs in current sediments due to the replacement of the deca-BDE mixture with DBDPE in this region. In addition, sediment concentrations of discontinued PBDEs in the rural area are clearly elevated due to e-waste dismantling. The congener profiles of PBDEs in the current sediments (with more abundant lower-brominated congeners) differed substantially from those in 2002 and from the technical products, suggesting that biological or photolytic debromination of PBDEs may have occurred in the environment. - Highlights: ► PBDE levels in sediments have decreased substantially since China's RoHS directive. ► Contamination of novel DBDPE has exceeded that of deca-BDE in the PRD sediments. ► The congener profiles of PBDEs in the sediments have changed significantly. ► Significant biological or photolytic degradation of PBDEs may occur in the environment

  13. Novel sensorless starting and low speed drive of cylindrical brushless DC motor using eddy current with un-known load; Uzudenryu wo riyoshita entogata brushless DC motor no futokutei fukaji ni okeru sensorless shidoho oyobi teisoku kudoho

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, M.; Doki, S.; Okuma, S. [Nagoya University, Nagoya (Japan); Yamaguchi, H. [The Aichi Electric Co. Ltd., Aichi (Japan)

    1998-04-01

    Sensorless starting and low speed drive of a cylindrical brushless DC motor with un-known load have been a difficult problem because an electromotive force does not arise enough at the starting and at low speeds and an inductance is constant irrespective of rotor position. In this paper, it is proposed to paste non-magnetic material and to measure a voltage of an opened phase to realize sensorless starting and low speed drives. The method is shown very feasible by experiments. 13 refs., 17 figs., 2 tabs.

  14. Challenges of equipment qualification using today's standards with emphasis on a class 1E motor program

    International Nuclear Information System (INIS)

    This paper describes qualification of new equipment for safety related service in the nuclear power industry in accordance with current industry standards. This topic is presented from the perspective of an original equipment manufacturer J(OEM). Equipment qualification is first discussed in a general way then an example is provided of an electric motor qualification. A review of alternative qualification methods including commercial dedication is included. Potential difficulties with alternative/expedited qualification methods are also discussed

  15. High-performance motor drives

    OpenAIRE

    Kazmierkowski, Marian P.; García Franquelo, Leopoldo; Rodríguez, José; Pérez, Marcelo; León Galván, José Ignacio

    2011-01-01

    This article reviews the present state and trends in the development of key parts of controlled induction motor drive systems: converter topologies, modulation methods, as well as control and estimation techniques. Two- and multilevel voltage-source converters, current-source converters, and direct converters are described. The main part of all the produced electric energy is used to feed electric motors, and the conversion of electrical power into mechanical power involves motors ranges from...

  16. Induction motor feedback current calculation and speed factor analysis%电压跌落时感应电动机反馈电流计算及转速影响研究

    Institute of Scientific and Technical Information of China (English)

    姜杰; 许宏; 陈贵文; 张太勤

    2014-01-01

    Large capacity induction machines have a great influence on short-circuit current level of industrial distribution network. Accurate calculation of the feedback current plays an important role in protection configuration and short-circuit current calculation. The motor speed changing during voltage drop is an important factor affecting the accuracy of feedback current calculation, regardless of the speed changing may cause error in feedback current calculation and affect the operation of protection. Using the positive and negative sequence steady-state equivalent circuit of induction motor and constant complex coefficient linear differential equations solving process, forced component and free component of stator/rotor flux linkage are solved. Then the induction motor feedback current formula in consideration of speed changing factor is deduced. Furthermore, the influence of speed on each component of the flux and feedback current is analyzed. The correctness of the proposed analysis is verified by the fifth electromagnetic transient model of induction motor in PSCAD/EMTDC simulation software.%大容量感应电动机会影响工业配网的短路电流水平,准确计算其反馈电流对系统保护配置及全网短路电流计算具有重要作用。电压跌落时电动机转速变化会影响电动机的反馈电流,不考虑转速变化可能会导致反馈电流计算结果不准确,影响保护的正确动作。利用感应电动机静态等值电路和复常系数线性微分方程组解法求解定转子磁链正负序强制分量和自由分量,进而得到电压跌落时计及转速变化的感应电动机反馈电流计算方法,并进一步探讨了转速对磁链和反馈电流各分量的影响。采用PSCAD/ EMTDC仿真软件中感应电动机的5阶动态模型仿真验证了该分析的正确性。

  17. Motor variability--an important issue in occupational life.

    Science.gov (United States)

    Srinivasan, Divya; Mathiassen, Svend Erik

    2012-01-01

    Several recent reviews have reported that 'repetitive movements' is a risk factor for occupational musculoskeletal disorders (MSD) in the neck, shoulder and arm regions. More variation in biomechanical exposure is often suggested as an effective intervention in such settings. While increasing variation using extrinsic methods like job rotation may not always be possible in an industrial context, the intrinsic variability of the motor system may offer an alternative opportunity to increase variation. Motor variability (MV) refers to the natural variation in postures, movements and muscle activity observed to different extents in all tasks. The current review explores the state of the art in MV research from motor control, sports and occupational biomechanics literature to answer whether MV is important to consider in an occupational context, and if yes, whether this literature stimulates further studies to test if MV can be manipulated as a deliberate intervention for increasing biomechanical variation without jeopardizing production. PMID:22317100

  18. A versatile stepping motor controller for systems with many motors

    Energy Technology Data Exchange (ETDEWEB)

    Feng, S.K.; Siddons, D.P.

    1989-01-01

    A versatile system for controlling beamlines or complex experimental setups is described. The system as currently configured can control up to 32 motors, with all motors capable of full speed operation concurrently. There are 2 limit switch inputs for each motor, and a further input to accept a reference position marker. The motors can be controlled via a front panel keyboard with display, or by a host computer over an IEEE-488 interface. Both methods can be used together if required. There is an emergency stop'' key on the front panel keyboard to stop the motion of all motors without losing track of the motors' position. 3 refs., 4 figs., 1 tab.

  19. Motor homopolar

    OpenAIRE

    2007-01-01

    Mostramos la construcción de un modelo de motor homopolar, uno de los más antiguos tipos de motores eléctricos. Se caracterizan porque el campo magnético del imán mantiene siempre la misma polaridad (de ahí su nombre, del griego homos, igual), de modo que, cuando una corriente eléctrica atraviesa el campo magnético, aparece una fuerza que hace girar los elementos no fijados mecánicamente. En el sencillísimo motor homopolar colgado (Schlichting y Ucke 2004), el imán puede girar ...

  20. A novel induction motor starting method using superconduction

    Science.gov (United States)

    Silva, F. B. B.; Orlando, M. T. D.; Fardin, J. F.; Simonetti, D. S.; Baldan, C. A.

    2014-12-01

    In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method.

  1. Motor “Dexterity”?: Evidence that Left Hemisphere Lateralization of Motor Circuit Connectivity Is Associated with Better Motor Performance in Children

    OpenAIRE

    Barber, Anita D.; Srinivasan, Priti; Joel, Suresh E.; Caffo, Brian S.; Pekar, James J.; Mostofsky, Stewart H.

    2011-01-01

    Motor control relies on well-established motor circuits, which are critical for typical child development. Although many imaging studies have examined task activation during motor performance, none have examined the relationship between functional intrinsic connectivity and motor ability. The current study investigated the relationship between resting state functional connectivity within the motor network and motor performance assessment outside of the scanner in 40 typically developing right...

  2. Application of stepping motor

    International Nuclear Information System (INIS)

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  3. Fault Detection based on MCSA for a 400Hz Asynchronous Motor for Airborne Applications

    Directory of Open Access Journals (Sweden)

    Steffen Haus

    2013-01-01

    Full Text Available Future health monitoring concepts in different fields of engineering require reliable fault detection to avoid unscheduled machine downtime. Diagnosis of electrical induction machines for industrial applications is widely discussed in literature. In aviation industry, this topic is still only rarely discussed.A common approach to health monitoring for electrical induction machines is to use Motor Current Signature Analysis (MCSA based on a Fast Fourier Transform (FFT. Research results on this topic are available for comparatively large motors, where the power supply is typically based on 50Hz alternating current, which is the general power supply frequency for industrial applications.In this paper, transferability to airborne applications, where the power supply is 400Hz, is assessed. Three phase asynchronous motors are used to analyse detectability of different motor faults. The possibility to transfer fault detection results from 50Hz to 400Hz induction machines is the main question answered in this research work. 400Hz power supply frequency requires adjusted motor design, causing increased motor speed compared to 50Hz supply frequency. The motor used for experiments in this work is a 800W motor with 200V phase to phase power supply, powering an avionic fan. The fault cases to be examined are a bearing fault, a rotor unbalance, a stator winding fault, a broken rotor bar and a static air gap eccentricity. These are the most common faults in electrical induction machines which can cause machine downtime. The focus of the research work is the feasibility of the application of MCSA for small scale, high speed motor design, using the Fourier spectra of the current signal.Detectability is given for all but the bearing fault, although rotor unbalance can only be detected in case of severe damage level. Results obtained in the experiments are interpreted with respect to the motor design. Physical interpretation are given in case the results differ

  4. Accumulation and Decay Characteristics of Exoelectron Sources at MgO Protective Layer Surface in Alternating-Current Plasma Display Panels

    Science.gov (United States)

    Yoshino, Kyohei; Nagatomi, Takaharu; Morita, Yukihiro; Oue, Toshiyasu; Kosugi, Naoki; Nishitani, Mikihiko; Kitagawa, Masatoshi; Takai, Yoshizo

    2010-08-01

    The accumulation and decay characteristics of exoelectron sources at a MgO protective layer surface in alternating-current plasma display panels (AC-PDPs) were investigated. The positively charged MgO surface provides a larger number of exoelectrons than the negatively charged surface, indicating that electrons trapped in shallow carrier traps coexist with trapped holes, and exoelectrons are emitted through Auger and/or photoionization processes after their recombination. The exoelectron sources are accumulated by sustain discharges and always decay. The half-life of the decay of the exoelectron sources is relatively long, of the order of a few tens of ms, confirming that the exoelectron emission property at the address discharge in a certain television (TV) field is strongly affected by sustain firings in the previous two TV fields or more. The effects of such a long-term decay of the exoelectron sources should be taken into consideration when designing the driving waveforms of AC-PDPs.

  5. Making a Simple Self-Starting Electric Motor

    Science.gov (United States)

    Hong, Seok-In; Choi, Jung-In; Hong, Seok-Cheol

    2009-01-01

    A simple electric motor has a problem in that the current applied to the motor per se can rarely trigger its rotation. Usually such motors begin to rotate after the rotor is slightly turned by hand (i.e., manual starting). In a "self-starting" motor, the rotor starts to rotate spontaneously as soon as the current is applied. This paper describes…

  6. Study on the Current Status of Medical Alternative Animal Researches%医学动物替代研究发展现状研究

    Institute of Scientific and Technical Information of China (English)

    卫茂玲

    2016-01-01

    目的:了解我国动物替代研究发展现状,发现问题,提出对策。方法文献检索与定性描述法。以主题、篇名或关键词“动物替代”或“动物减少”或“动物优化”精确检索中文医学常用数据库中国知网、维普数据和万方数据库,补充查找相关研究参考文献。纳入分析组织建设、立法、医学教育和替代研究方法文献,并进行定性描述概括,检索时间截止2015年7月20日。结果初检引文219条,文献发表于1999-2014年,以描述性研究为主。动物替代研究领域包括皮肤刺激、眼刺激毒理学检测、热敏试验和动物模型替代等。替代研究信息交流平台已建立,部分教师已经在实践运用替代原则,相关专著已出版,但法规建设和验证体系滞后,替代研究认识还不乐观,验证方法研究不多。结论国内动物替代研究不多,缺乏系统化建设。未来应加强动物替代研究体系研究,重点在立法、政策引导、医学教育、人才培养和研究方法等。%Objective:To investigate the current status of alternative animal researches in China and thus find the problems and put forward countermeasures. Method: This study was carried out by the methods of literature search and qualitative description. The authors precisely searched the medicine databases commonly used in China ( CNKI, VIP, and Wanfang Data) using the MeSH word, title, or keyword namely"animal alternative","animal decrease" or"animal optimization", and added to find the related researches′references. Then the author included the literature regarding to the organization construction, legislation, medical education, and alternative research methods, and conducted a qualitative description. The deadline was July 20, 2015. Results:There were 219 ini-tial quotations published from 1999 to 2014, and mainly were descriptive researches. The fields of alternative ani-mal researches included skin

  7. Pulse-Width-Modulating Driver for Brushless dc Motor

    Science.gov (United States)

    Salomon, Phil M.

    1991-01-01

    High-current pulse-width-modulating driver for brushless dc motor features optical coupling of timing signals from low-current control circuitry to high-current motor-driving circuitry. Provides high electrical isolation of motor-power supply, helping to prevent fast, high-current motor-driving pulses from being coupled through power supplies into control circuitry, where they interfere with low-current control signals.

  8. 交流发光二极管热特性的模拟分析%Thermal Simulation of Alternating Current Light Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    邓辉; 陈忠; 吕毅军; 高玉琳; 朱丽虹; 陈莹亮; 林岳; 郭自泉; 王凯; 陈国龙

    2012-01-01

    由于交流发光二极管(AC-LED)在实际应用中无需交流/直流整流变压器,它的发展越来越被关注.随着器件功率的增大,芯片结温升高,对器件的光通量、光功率及寿命等产生负面影响,所以精确掌握AC-LED的温升规律就成为芯片设计的关键.运用FloEFD有限元软件进行模拟仿真1W白光AC-LED分别在直流和交变功率驱动下的瞬态热特性,结果表明在加载交变信号情况下,器件结温会以直流信号的结温为中心周期振荡,振荡的频率与输入功率频率相同,但有明显的相位移动.同时,AC-LED在不同的输入功率和频率下的结温变化显示稳态时的平均结温和结温振荡幅度都随功率的增大而线性上升,但随着频率的增大而降低.%Alternating current light emitting diodes (AC-LED) have attracted more and more attentions due to the advantage of free of alternate current (AC)/direct current (DC) converter in practical application. With the increase of input power, the rising junction temperature will have negative influence on the the luminous flux, the optical power, the lifetime and other parameters of LED. Therefore, the understanding of the principle of accurate temperature rise of AC-LED is the key to the chip design. The finite-element analysis software (FloEFD) is used to simulate the transient thermal properties of 1 W white AC-LED driven by DC and AC power respectively. The results show that the junction temperature of AC-LED driven by AC power, fluctuates periodically around that driven by DC power and the fluctuation frequency is the same as that of the input signal, but with an apparent phase shift. Meanwhile, the variation of junction temperature of AC-LED driven at different powers and frequencies shows that the average junction temperature and its fluctuation amplitude increases linearly with the input power at steady state, however, decreases with the increase of frequency.

  9. Overview of Current Loop Control Technology for Permanent Magnet Synchronous Motor Servo System%永磁同步电机伺服系统电流环控制技术综述

    Institute of Scientific and Technical Information of China (English)

    黄玉平; 郑再平; 仲悦; 吴红星

    2015-01-01

    The current loop is the most inner and important loop for permanent magnet synchronous motor servo system in the three control loops.The current loop control method and control technology has a direct impact on the dynamic performance of the whole system.Based on the analysis of permanent magnet synchro-nous motor mathematical model and vector control principle, the paper carried on the summary of the domes-tic and foreign research method and control strategy of current control of permanent magnet synchronous mo-tor control system in the three control loops.The operation characteristics of the novel current regulator and current decoupling method in the control system were analyzed.The current decoupling method on back elec-tromotive force compensation technology research and development were investigated and the current control technique was summarized.%电流环是永磁同步电机伺服系统三环控制最内,也是最重要的控制环节,电流环控制方法和控制技术的好坏直接影响整个系统的动态性能。本文在分析永磁同步电动机数学模型和矢量控制原理的基础上,针对永磁同步电机三环控制系统中的电流环控制国内外研究的方法和控制策略进行综述,分析新型电流调节器在控制系统中的作用及工作特点,探讨现有的电流解耦方法对反电势补偿技术研究发展动态,并对电流控制技术进行总结。

  10. Alternative Solar Indices

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.

    1980-07-01

    Possible alternative Solar Indices which could either be a perturbation from the currently defined Solar Index or possible indices based on current technologies for other media markets are discussed. An overview is given of the current project, including the logic that was utilized in defining its current structure and then alternative indices and definitions are presented and finally, recommendations are made for adopting alternative indices.

  11. Flood-proof motors

    International Nuclear Information System (INIS)

    Even before the Fukushima event occurred some German nuclear power plants (NPP) have considered flooding scenarios. As a result of one of these studies, AREVA performed an upgrade project in NPP Isar 1 with flood-proof motors as a replacement of existing air-cooled low-voltage and high-voltage motors of the emergency cooling chain. After the Fukushima event, in which the cooling chains failed, the topic flood-proof equipment gets more and more into focus. This compact will introduce different kinds of flood-proof electrical motors which are currently installed or planned for installation into NPPs over the world. Moreover the process of qualification, as it was performed during the project in NPP Isar 1, will be shown. (orig.)

  12. High-Tc superconducting electric motors

    International Nuclear Information System (INIS)

    In this paper, the advantages and limitations of using superconductors in motors are discussed. A synchronous motor with a high temperature superconducting field winding for pump and fan drive applications is described and some of its unique design features are identified. A 10,000 horsepower superconducting motor design is presented. The critical field and current density requirements for high temperature superconducting wire in motors is discussed. Finally, recent progress in superconducting wire performance is presented

  13. MODELING PENGATURAN KECEPATAN MOTOR DC DENGAN SIMULINK

    OpenAIRE

    IN Satya Kumara

    2009-01-01

    Motor arus searah (motor dc), khususnya tipe penguatan terpisah, memiliki karakteristik pengaturan kecepatan yang sangat baik, karena flux-producing dan torque-producing components currents dalam keadaan independen satu sama lain. Hal ini terjadi karena konstruksi fisik motor dc dimana komponen arus yang menghasilkan torsi dan komponen arus yang menghasilkan fluk sudah terdekopel secara alami. Dengan demikian pengaturan kecepatan motor bisa dilakukan dengan teknik pengaturan yang tidak rumit ...

  14. Validating the Rett Syndrome Gross Motor Scale

    OpenAIRE

    Jenny Downs; Michelle Stahlhut; Kingsley Wong; Birgit Syhler; Anne-Marie Bisgaard; Peter Jacoby; Helen Leonard

    2016-01-01

    Rett syndrome is a pervasive neurodevelopmental disorder associated with a pathogenic mutation on the MECP2 gene. Impaired movement is a fundamental component and the Rett Syndrome Gross Motor Scale was developed to measure gross motor abilities in this population. The current study investigated the validity and reliability of the Rett Syndrome Gross Motor Scale. Video data showing gross motor abilities supplemented with parent report data was collected for 255 girls and women registered with...

  15. Mechatronical Design Studies on Small Brushless Motors

    OpenAIRE

    W. Amrhein; S. Silber; K. Nenninger; Trauner, G.; R. Schöb

    2003-01-01

    Brushless DC- and AC-permanent-magnet motors controlled by powerful micro-controller electronics have opened up a significant share of the small motor market in the last years. Based on the mechanical low cost construction of single-phase motor the paper presents electronic drive concepts to improve the performance and for special applications also the lifetime of brushless motors. The tangential and radial forces acting on the rotor are controlled by special phase current curves to reduce th...

  16. Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xinhua Guo

    2016-07-01

    Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

  17. Four quadrant control circuit for a brushless three-phase dc motor

    Science.gov (United States)

    Nola, Frank J. (Inventor)

    1987-01-01

    A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.

  18. Chaos control of the brushless direct current motor using adaptive dynamic surface control based on neural network with the minimum weights

    International Nuclear Information System (INIS)

    This paper investigates chaos control for the brushless DC motor (BLDCM) system by adaptive dynamic surface approach based on neural network with the minimum weights. The BLDCM system contains parameter perturbation, chaotic behavior, and uncertainty. With the help of radial basis function (RBF) neural network to approximate the unknown nonlinear functions, the adaptive law is established to overcome uncertainty of the control gain. By introducing the RBF neural network and adaptive technology into the dynamic surface control design, a robust chaos control scheme is developed. It is proved that the proposed control approach can guarantee that all signals in the closed-loop system are globally uniformly bounded, and the tracking error converges to a small neighborhood of the origin. Simulation results are provided to show that the proposed approach works well in suppressing chaos and parameter perturbation

  19. Chaos control of the brushless direct current motor using adaptive dynamic surface control based on neural network with the minimum weights.

    Science.gov (United States)

    Luo, Shaohua; Wu, Songli; Gao, Ruizhen

    2015-07-01

    This paper investigates chaos control for the brushless DC motor (BLDCM) system by adaptive dynamic surface approach based on neural network with the minimum weights. The BLDCM system contains parameter perturbation, chaotic behavior, and uncertainty. With the help of radial basis function (RBF) neural network to approximate the unknown nonlinear functions, the adaptive law is established to overcome uncertainty of the control gain. By introducing the RBF neural network and adaptive technology into the dynamic surface control design, a robust chaos control scheme is developed. It is proved that the proposed control approach can guarantee that all signals in the closed-loop system are globally uniformly bounded, and the tracking error converges to a small neighborhood of the origin. Simulation results are provided to show that the proposed approach works well in suppressing chaos and parameter perturbation. PMID:26232953

  20. Chaos control of the brushless direct current motor using adaptive dynamic surface control based on neural network with the minimum weights

    Science.gov (United States)

    Luo, Shaohua; Wu, Songli; Gao, Ruizhen

    2015-07-01

    This paper investigates chaos control for the brushless DC motor (BLDCM) system by adaptive dynamic surface approach based on neural network with the minimum weights. The BLDCM system contains parameter perturbation, chaotic behavior, and uncertainty. With the help of radial basis function (RBF) neural network to approximate the unknown nonlinear functions, the adaptive law is established to overcome uncertainty of the control gain. By introducing the RBF neural network and adaptive technology into the dynamic surface control design, a robust chaos control scheme is developed. It is proved that the proposed control approach can guarantee that all signals in the closed-loop system are globally uniformly bounded, and the tracking error converges to a small neighborhood of the origin. Simulation results are provided to show that the proposed approach works well in suppressing chaos and parameter perturbation.

  1. Chaos control of the brushless direct current motor using adaptive dynamic surface control based on neural network with the minimum weights

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shaohua [School of Automation, Chongqing University, Chongqing 400044 (China); Department of Mechanical Engineering, Chongqing Aerospace Polytechnic, Chongqing, 400021 (China); Wu, Songli [Department of Mechanical Engineering, Chongqing Aerospace Polytechnic, Chongqing, 400021 (China); Gao, Ruizhen [School of Automation, Chongqing University, Chongqing 400044 (China)

    2015-07-15

    This paper investigates chaos control for the brushless DC motor (BLDCM) system by adaptive dynamic surface approach based on neural network with the minimum weights. The BLDCM system contains parameter perturbation, chaotic behavior, and uncertainty. With the help of radial basis function (RBF) neural network to approximate the unknown nonlinear functions, the adaptive law is established to overcome uncertainty of the control gain. By introducing the RBF neural network and adaptive technology into the dynamic surface control design, a robust chaos control scheme is developed. It is proved that the proposed control approach can guarantee that all signals in the closed-loop system are globally uniformly bounded, and the tracking error converges to a small neighborhood of the origin. Simulation results are provided to show that the proposed approach works well in suppressing chaos and parameter perturbation.

  2. Peculiar Features of Burning Alternative Motor Fuels

    Directory of Open Access Journals (Sweden)

    M. Assad

    2006-01-01

    Full Text Available Some peculiar features of air-hydrogen mixture combustion process in a modeling combustion chamber are given in the paper. Dependences of burning duration of various fuel types on initial pressure have been obtained. The paper considers dynamics of changes in pressure and ignition rate of some fuel types in the combustion chamber.

  3. Analysis of water flow, power and electrical current of a motor pump powered by photovoltaic panels; Analise da vazao, potencia e corrente em uma motobomba acionada por paines fotovoltaicos

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Paulo Takashi; Santos, Jose Airton Azevedo dos; Michels, Roger Nabeyama [Universidade Tecnologica Federal do Parana (UTFPR-MD), Medianeira, PR (Brazil)], E-mail: airton@utfpr.edu.br; Ricieri, Reinaldo Prandini [Universidade do Oeste Paulista (UNIOESTE), Cascavel, PR (Brazil). Dept. de Engenharia Agricola], E-mail: ricieri@unioeste.br; Halmeman, Maria Cristina Rodrigues [Universidade Tecnologica Federal do Parana (UTFPR-CM), Campo Mourao, PR (Brazil)

    2009-07-01

    Because of the high cost of electricity connection to distant places, far away from conventional nets, photovoltaic solar energy is widely used in public illumination, water pumping, medical care centers, etc. With the purpose to contribute to a better utilization in this type of energy, the object of the project is to analyze the water flow, power and electrical current of a motor pump to be used for water lift, driven by photovoltaic panels, the data will be collected at every 2 meters in height from 2.2 to 18.2 meters. The analyses show the outflow linear dependence in relation to the height of the water lift, a second order dependence of the electrical power provided by the photovoltaic panels in relation to the solar irradiance on the panels and a linear dependence of the electrical current in relation to the solar irradiance. This study is a part of a project developed at the 'Universidade Tecnologica Federal do Parana' (UTFPR) - Campus Medianeira - PR. Two photovoltaic panels were used from Solarex Brand, model MSX 56, a motor pump made by Shurflo Ltd, model 2088-732, two pyranometers from KIPP and ZONEN CM3, a type K thermocouple, a pressure transducer model HUBA-510 and a water flow transducer. (author)

  4. Analysis of Rotor Eddy-current Loss in High-speed Permanent Magnet Motors%高速永磁电机的转子涡流损耗分析

    Institute of Scientific and Technical Information of China (English)

    高鹏飞; 房建成; 韩邦成; 孙津济

    2013-01-01

    For high-speed permanent magnet motors,the rotor eddy-current loss cannot be underestimated in that it has serious implications on the motors' efficiency or even demagnetizes the permanent magnets because of the overheating problem.The sources of the harmonics which produce the rotor eddy-current loss were put forward,and the analytical calculation was presented,then the loss of different motor structures were analyzed,and the influences of various stator slot numbers,slot opening width,airgap length,the shield and the auxiliary slot were studied.The results show that the rotor eddy-current loss can be reduced by more slots,thinner slot opening width and larger airgap length.It also comes to the conclusion that a shield with high conductivity between the retaining sleeve and permanent magnets can reduce the rotor eddy-current loss,and a proper thickness of the shied can help to minimize the loss.The auxiliary slot is studied,and with proper width,depth angle and type,the auxiliary slot can be used to reduce the rotor eddy-current loss and cool the motors.The research is of great value in theory and engineer applications for high-speed permanent magnet motors.%在高速永磁电机中,转子涡流损耗会使转子温度升高,影响电机效率等性能,甚至导致永磁体过热退磁.针对高速永磁电机中的转子涡流损耗问题,进行了解析分析和有限元计算,分析了产生转子涡流损耗的谐波来源,研究了不同定转子结构电机的转子涡流损耗,分析了定子槽数、槽口宽度、气隙长度、屏蔽层、定子齿开辅助槽对转子涡流损耗的影响.结果表明,增加定子槽数、减小槽口宽度、增加气隙长度可以减小转子涡流损耗;在护套和永磁体中间加一层高电导率屏蔽层能有效减小永磁体的涡流,且选择合适的屏蔽层厚度能够进一步减小转子涡流损耗;提出了使用合适宽度、深度、角度和槽型的辅助槽来减小转子涡流损耗、

  5. Alternative current conduction mechanisms of organic-inorganic compound [N(CH3)3H]2ZnCl4

    Science.gov (United States)

    Ben Bechir, M.; Karoui, K.; Tabellout, M.; Guidara, K.; Ben Rhaiem, A.

    2014-04-01

    [N(CH3)3H]2ZnCl4 has been studied by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and impedance spectroscopy. The [N(CH3)3H]2ZnCl4 hybrid compound is crystallized at room temperature (T ≈ 300 K) in the orthorhombic system with Pnma space group. Five phase transitions (T1 = 255 K, T2 = 282 K, T3 = 302 K, T4 = 320 K, and T5 = 346 K) have been proved by DSC measurements. The electrical technique was measured in the 10-1-107 Hz frequency range and 233-363 K temperature interval. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law. The AC electrical conduction in [N(CH3)3H]2ZnCl4 is analyzed by different processes, which can be attributed to several models: the correlated barrier hopping model in phase I, the overlapping large polaron tunneling model in phase II, the quantum mechanical tunneling model in phase IV, and the non-overlapping small polaron tunneling model in phases III, V, and VI. The conduction mechanism is studied with the help of Elliot's theory, and the Elliot's parameters are determined.

  6. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    International Nuclear Information System (INIS)

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system

  7. Anomalous Oxide Charge Variation Identified by Alternating Current Surface Photovoltage Method in Cr-Aqueous-Solution-Rinsed p-Type Si(001) Wafers Exposed to Air

    Science.gov (United States)

    Shimizu, Hirofumi; Sanada, Yuji

    2011-11-01

    Chromium (Cr)-aqueous-solution-rinsed and/or hydrofluoric acid (HF)-solution-dipped p-type silicon (Si) (001) wafer surfaces are investigated by the frequency-dependent alternating current (AC) surface photovoltage (SPV) method. At the Cr(OH)3/p-type Si interface, in principle, a Schottky barrier could not possibly be generated. The Cr ion (Cr3+) is considered to forcibly deprive a p-type Si substrate of electrons during metallization (Cr3++3e-→Cr). Thus, at an early stage of air exposure, a positive fixed oxide charge may be compensated for by electrons, indicating the disappearance of AC SPV. With air exposure time, AC SPV emerges again and increases gradually in a Cr-deposited p-type Si(001) surface. This is because the native oxide between the Cr atom layer and the p-type Si substrate grows with time. As a result, a positive fixed oxide charge exceeds the overall charge state of the Cr-deposited p-type Si surface. Thus, AC SPV appears again and gradually increases with the fixed oxide charge in p-type Si. The saturated value is in a good agreement with that of the HF aqueous-solution-dipped p-type Si surface.

  8. Metal-induced negative oxide charge detected by an alternating current surface photovoltage in thermally oxidized Fe-contaminated n-type Si (001) wafers

    International Nuclear Information System (INIS)

    The atomic-bridging type negative oxide charge in SiO2 is investigated using the Fe-contaminated (001) surface of n-type Si wafers. The investigation is done on the basis of a chemical analysis and a method in which the frequency-dependent alternating current (AC) surface photovoltage (SPV) is measured. At room temperature, an AC SPV appears and gradually increases, saturating after approximately one day (with an Fe concentration on the Si surface of 4.0 × 1013 atoms/cm2). The AC SPV eventually becomes inversely proportional to frequency except at very low frequencies (− network. Also, in Fe-contaminated n-type Si(001) surfaces thermally oxidized at between 550 and 650 °C for 60 min, strong inversion is unquestionably observed, proving that the (FeOSi)− network survives and that most of the added Fe has segregated into the region closest to the surface of the thin SiO2 film. At 850 °C and/or for long oxidation times, the AC SPV decreases and ultimately disappears, implying that the (FeOSi)− network has collapsed and may have changed into Fe2O3. A model for the metal-induced negative oxide charge in the conventional oxide charge diagram is proposed.

  9. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Murillo L., E-mail: murillolongo@gmail.com [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Calabresi, Marcos F.; Quini, Caio; Matos, Juliana F.; Miranda, José R.A.; Saeki, Margarida J. [Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Bordallo, Heloisa N. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

    2015-03-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system.

  10. Motor Magnates

    Institute of Scientific and Technical Information of China (English)

    ISABEL DING

    2008-01-01

    @@ The automotive industry is often seen as a man's world. Wang Fengying (王风英) begs to differ. The 38-year-old has presided over Great Wall Motors (长城汽车), the leading pick-up truck and Sport Utility Vehicle(SUV) manufacturer in China for the past five years.

  11. THE MOTOR

    DEFF Research Database (Denmark)

    Gammelgaard Nielsen, Anders

    2011-01-01

    MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...

  12. Motor radiculopathy

    OpenAIRE

    Khan, Afsha; Camilleri, Jeremy

    2012-01-01

    A 48-year-old immunosuppressed woman presented to a rheumatology follow-up clinic after suffering from herpes zoster infection. She had manifestations of foot drop 3 months after the initial infection. She was diagnosed with motor radiculopathy following herpes zoster infection that was effectively managed by physiotherapy and amitriptyline.

  13. Motor cortical plasticity induced by motor learning through mental practice.

    Directory of Open Access Journals (Sweden)

    Nicolas Gueugneau

    2015-04-01

    Full Text Available Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1 excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after physical practice and motor-imagery practice, M1 excitability was evaluated by measuring the input-output (IO curve of motor evoked potentials. M1 long-term potentiation (LTP and long-term depression (LTD-like plasticity was assessed with paired-associative stimulation (PAS of the median nerve and motor cortex using an interstimulus interval of 25 ms (PAS25 or 10 ms (PAS10, respectively. We found that even if after both practice sessions subjects significantly improved their movement speed, M1 excitability and plasticity were differentially influenced by the two practice sessions. First, we observed an increase in the slope of IO curve after physical but not after motor-imagery practice. Second, there was a reversal of the PAS25 effect from LTP-like plasticity to LTD-like plasticity following physical and motor-imagery practice. Third, LTD-like plasticity (PAS10 protocol increased after physical practice, whilst it was occluded after motor-imagery practice. In conclusion, we demonstrated that motor-imagery practice lead to the development of neuroplasticity, as it affected the PAS25- and PAS10- induced plasticity in M1. These results, expanding the current knowledge on how motor-imagery training shapes M1 plasticity, might have a potential impact in

  14. Summary of electric vehicle dc motor-controller tests

    Science.gov (United States)

    Mcbrien, E. F.; Tryon, H. B.

    1982-01-01

    The differences in the performance of dc motors are evaluated when operating with chopper type controllers, and when operating on direct current. The interactions between the motor and the controller which cause these differences are investigated. Motor-controlled tests provided some of the data the quantified motor efficiency variations for both ripple free and chopper modes of operation.

  15. 46 CFR 169.675 - Generators and motors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Generators and motors. 169.675 Section 169.675 Shipping... Less Than 100 Gross Tons § 169.675 Generators and motors. (a) Each generator and motor must be fitted... applicable. (10) Type of winding (for direct-current motors). (b) Each vessel of more than 65 feet in...

  16. A novel fault tolerant permanent magnet synchronous motor with improved optimal torque control for aerospace application

    Directory of Open Access Journals (Sweden)

    Guo Hong

    2015-04-01

    Full Text Available Improving fault tolerant performance of permanent magnet synchronous motor has always been the central issue of the electrically supplied actuator for aerospace application. In this paper, a novel fault tolerant permanent magnet synchronous motor is proposed, which is characterized by two stators and two rotors on the same shaft with a circumferential displacement of mechanical angle of 4.5°. It helps to reduce the cogging torque. Each segment of the stator and the rotor can be considered as an 8-pole/10-slot five-phase permanent magnet synchronous motor with concentrated, single-layer and alternate teeth wound winding, which enhance the fault isolation capacity of the motor. Furthermore, the motor has high phase inductance to restrain the short-circuit current. In addition, an improved optimal torque control strategy is proposed to make the motor work well under the open-circuit fault and short-circuit fault conditions. Simulation and experiment results show that the proposed fault tolerant motor system has excellent fault tolerant capacity, which is able to operate continuously under the third open-circuit fault and second short-circuit fault condition without system performance degradation, which was not available earlier.

  17. System and method for determining stator winding resistance in an AC motor using motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  18. Why were alternating-current-driven electrochemiluminescence properties from Ru(bpy)3(2+) dramatically improved by the addition of titanium dioxide nanoparticles?

    Science.gov (United States)

    Tsuneyasu, Shota; Ichihara, Kazuki; Nakamura, Kazuki; Kobayashi, Norihisa

    2016-06-28

    Electrochemiluminescence (ECL) is a phenomenon in which light is emitted from the excited state of a redox-active material generated by electrochemical reactions. Among light-emitting devices, ECL devices have various advantages in terms of structure and ease of fabrication, and therefore, they are expected to be next-generation emitting devices. In this study, we introduced rutile-type titanium dioxide nanoparticles (TiO2 NPs) in a Ru(ii)-complex-based electrolyte to improve the emission properties of an alternating current (AC)-driven ECL device. The properties of the ECL device with TiO2 NPs were greatly improved (emission luminescence, 165 cd m(-2); half-life time, 1000 s) compared to a previously reported AC-driven ECL device without nanoparticles. To determine how TiO2 NPs helped in achieving high emission luminescence and long-term stability, we measured the optical and electrochemical properties of the Ru(bpy)3(2+)-based ECL solution in detail. The PL intensity of Ru(bpy)3(2+) was increased by adding TiO2 NPs, which indicated that the suppression of non-radiative quenching of the complex's excited states could improve the ECL intensity. With respect to the enhanced stability, electron transfers between Ru(bpy)3(2+) and TiO2 were suggested by detailed electrochemical measurements. These electron transfers occurred from the reduced Ru(bpy)3(2+) species to the TiO2, and subsequently, from the TiO2 to the oxidized Ru(bpy)3(2+) species. Such electron transfers are thought to improve the balance of the redox reactions in the ECL device, leading to long-term stability. PMID:27253475

  19. Metal-induced negative oxide charge detected by an alternating current surface photovoltage in thermally oxidized Fe-contaminated n-type Si (001) wafers

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Hirofumi, E-mail: shimizuh@ee.ce.nihon-u.ac.jp; Otsuki, Tomohiro

    2012-05-01

    The atomic-bridging type negative oxide charge in SiO{sub 2} is investigated using the Fe-contaminated (001) surface of n-type Si wafers. The investigation is done on the basis of a chemical analysis and a method in which the frequency-dependent alternating current (AC) surface photovoltage (SPV) is measured. At room temperature, an AC SPV appears and gradually increases, saturating after approximately one day (with an Fe concentration on the Si surface of 4.0 Multiplication-Sign 10{sup 13} atoms/cm{sup 2}). The AC SPV eventually becomes inversely proportional to frequency except at very low frequencies (< 10 Hz) corresponding to weak or strong inversion, indicating that the negative Fe induced oxide charge appears in the form of a (FeOSi){sup -} network. Also, in Fe-contaminated n-type Si(001) surfaces thermally oxidized at between 550 and 650 Degree-Sign C for 60 min, strong inversion is unquestionably observed, proving that the (FeOSi){sup -} network survives and that most of the added Fe has segregated into the region closest to the surface of the thin SiO{sub 2} film. At 850 Degree-Sign C and/or for long oxidation times, the AC SPV decreases and ultimately disappears, implying that the (FeOSi){sup -} network has collapsed and may have changed into Fe{sub 2}O{sub 3}. A model for the metal-induced negative oxide charge in the conventional oxide charge diagram is proposed.

  20. Energy Efficiency Standards of Induction Motors, ¿Are you Prepared Latin America?

    Directory of Open Access Journals (Sweden)

    Carlos M. Londoño-Parra

    2013-06-01

    Full Text Available In Colombia the regulatory process regarding the energy efficiency of end-use prod-ucts is emerging with the draft technical regulation product labeling RETIQ, which includes in Annex E, the test methods for determining the efficiency of motors alternat-ing current induction. The goal of this paper is to compare the energy efficiency of induction motors between the countries of Latin America and the countries of the major economies of the globe, considering four aspects: the current state of classification standards and test procedures of induction motors efficiency, multilateral agreements of mutual recognition, the infrastructure to conduct tests of the standard and support programs to improve the efficiency of electric motor-driven systems. The study reveals that Latin America is a considerable delay in the implementation of classification standards and methods for testing the efficiency of electric motors, most widely used in the world: IEC 60034-30:2008, IEC 60034-2-1: 2007 IEEE 112:2004 and EPAct'92, with respect to the countries of the European Union, United States, China, Australia, and other developed countries, in which these standards have been adopted. Furthermore, the region is evident in the absence of programs focused on improving the energy efficiency of electric motors and a limited number of accredited laboratories to evaluate their efficiency, which leads to most Latin American countries to establish agreements mutual recognition for this purpose.

  1. Energy Efficiency Standards of Induction Motors, ¿Are you Prepared Latin America?

    Directory of Open Access Journals (Sweden)

    Carlos M. Londoño-Parra

    2013-06-01

    Full Text Available In Colombia the regulatory process regarding the energy efficiency of end-use products is emerging with the draft technical regulation product labeling RETIQ, which includes in Annex E, the test methods for determining the efficiency of motors alternating current induction. The goal of this paper is to compare the energy efficiency of induction motors between the countries of Latin America and the countries of the major economies of the globe, considering four aspects: the current state of classification standards and test procedures of induction motors efficiency, multilateral agreements of mutual recognition, the infrastructure to conduct tests of the standard and support programs to improve the efficiency of electric motor-driven systems. The study reveals that Latin America is a considerable delay in the implementation of classification standards and methods for testing the efficiency of electric motors, most widely used in the world: IEC 60034-30:2008, IEC 60034-2-1: 2007 IEEE 112:2004 and EPAct'92, with respect to the countries of the European Union, United States, China, Australia, and other developed countries, in which these standards have been adopted. Furthermore, the region is evident in the absence of programs focused on improving the energy efficiency of electric motors and a limited number of accredited laboratories to evaluate their efficiency, which leads to most Latin American countries to establish agreements mutual recognition for this purpose.

  2. DC Motor Control Predictive Models

    OpenAIRE

    Ravinesh Singh; Godfrey C. Onwubolu; Krishnileshwar Singh; Ritnesh Ram

    2006-01-01

    DC motor speed and position controls are fundamental in vehicles in general and robotics in particular. This study presents a mathematical model for correlating the interactions of some DC motor control parameters such as duty cycle, terminal voltage, frequency and load on some responses such as output current, voltage and speed by means of response surface methodology. For this exercise, a five-level full factorial design was chosen for experimentation using a peripheral interface controller...

  3. Improving the energy indicators of thyristor electric drive with asynchronous short-circuited motor of a deep pump unit by negative feedback

    Energy Technology Data Exchange (ETDEWEB)

    Aliyev, E.S.

    1983-01-01

    At the department of electric drive and automation of industrial units of the M. Azizbekov Azerbaijan Institute of Petrochemistry a system was developed for automated thyristor electric drive of alternating current with asynchronous short-circuited electric motor for smooth regulation of the output of a deep-pump unit, which at the same time makes it possible to improve the energy efficiency of the electric drive of the pumping unit with quasi steady-state mode of changing the voltage on the motor stator according to the load by using negative feedback for the rotation frequency of the motor.

  4. High Performance Speed Sensorless Control of Three-Phase Induction Motor Based on Cloud Computing

    Directory of Open Access Journals (Sweden)

    Z. M. Salem

    2012-10-01

    Full Text Available Induction motor is a cast of alternating current motor where charge endures allotted to the rotor close-at-hand deputation of conductive charge. These motors are broadly applied in industrial claim due to they are arduous along with adhere no contacts. The speed controller of deltoid phase induction motor is applied to alleviate the aberration of speed. The central constructivist of this paper is to accrue the performance of speed sensorless control of three phase induction motor. To increase its performance, this paper presents a modified method for speed controller of an indirect vector-controlled induction motor drive using cloud computing technique. Our methodology depends on speed sensorless scheme to obtain the speed signal feedback; the speed estimator is based on model reference adaptive control that uses the stator current and rotor flux as state variables for estimating the speed. In this method, the stator current error is represented as a function of first degree of the estimated speed error. An analysis and simulation of the tried algorithm is birthed and applied easing a TMS320C31 floating-point notational alert Processor. And accumulate the action of the three phase induction motor we conceived our appraisals affixed to the accountant based on cloud computing tactics. This intelligent policy uses the guidelines of the speed controller efficiently. Simulation and experimental results depicted that the motor speed is decelerated articulately to destine its illusion apprise without above and inferior smack and with about zero steady state error. The apprised accelerate alert and its dispatching buoy amassed off line from burlesque. After effects display an advantageous affinity among the accounted speed alert and it's dispatching allocated as well as aped speed flares

  5. High speed DC brushless motor controlled by microntroller

    International Nuclear Information System (INIS)

    The paper presents an example of DC Brushless motor used to rotate high vacuum turbo molecular pumps. Both the motor and the electronic drive system, controlled by microcontroller PIC16F877, are designed and made in our institute. DC Brushless motors are one of the motor types which have had the fastest development. This type of motor is especially used in industries such as Industrial Automation Equipment and Instrumentation, Medical, Automotive etc. DC Brushless motors do not use brushes for commutation of the current. The phase of the motor are electronically commutated. Comparative with DC Brushed motors and induction motors, DC Brushless motors have the followings advantages: -high speed ranges; - long operating life; - high efficiency; -better speed versus torque characteristics; - high dynamic response; - noiseless operation; Also, the ratio of torque provided to the size of the motor is higher, making it useful in applications where space and weight are limited. (authors)

  6. Energy alternatives

    International Nuclear Information System (INIS)

    Due to sharp rise in oil proces after the 1973 Arab-Israeli War, world attention has been focussed on the energy problem. At present the energy problem is limited to the cost and reliability of supply, even though there are enough supplies to go round. However, in the future the problem will be of availability, because in spite of the full exploitation of currently available conventional energy sources, the supply will fall short of demand which will always be increasing. Hence, there is need to develop alternate energy sources, including fast breeder reactors, fusion reactors and MHD. Economic and technical aspects of these energy are discussed. (M.G.B.)

  7. Improved Rotor Speed Brushless DC Motor Using Fuzzy Controller

    OpenAIRE

    Jafar Mostafapour; Jafar Reshadat; Murtaza Farsadi

    2015-01-01

    A brushless DC (BLDC) Motors have advantages over brushed, Direct current (DC) Motors and , Induction motor (IM). They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive...

  8. IMPLEMENTATION AND STUDY OF BLDC MOTOR DRIVE SYSTEM

    OpenAIRE

    Amol R. Sutar*, G. G. Bhide, J. J. Mane

    2016-01-01

    The BLDC motor  is an electronically commutated dc motor becoming very popular in many applications. There are various speed control methods used for BLDC motor. The performance of BLDC motor drives can be improved using sensored control techniques over sensorless technology. This paper presents Brushless Direct Current motor drive system and its sensored speed control technique with PWM.  Advantages and limitations of sensorless techniques are reviewed and then, sensored speed cont...

  9. Algorithm of Alternating Current Schedule Power Flow for Bulk Interconnected Grid%大型互联电网交流计划潮流算法

    Institute of Scientific and Technical Information of China (English)

    丁平; 李亚楼; 田芳; 李柏青; 严剑峰; 于之虹; 周孝信; 罗志强

    2014-01-01

    In China Power Grid, calculation of alternating current schedule power flow is an important foundation for checking security of schedule. An algorithm of AC schedule power flow applied to bulk interconnected power system was put forward in this paper. The principle of calculating was set firstly, which include four points, namely faithfulness, diversity by area, reality, selectable. Then solution based on interfaces controlling method was given. An approach to active schedule step by step was offered with three means of distributing unbalance power. To regulate reactive power, a method taking advantage of react power arranged in similar power flow was employed, which included using voltage of similar power flow as initial and determining parameter variation referring to closeness between active power of schedule and similar power flow. The algorithm was validated by cases from IEEE 39-node and China State Grid. The algorithm proposed is convergent well, can give power flow close to schedule data and situation appearing in power system, and owns good value for popularization and application.%在中国电网,交流计划潮流计算是校核计划安全性的重要基础。该文提出适用于大型互联电网的交流计划潮流算法。首先确立计算必须遵循的忠实性、分区域、真实性和可选择等4个原则;然后给出基于多断面控制法的实现方案。提出分阶段逐步逼近有功计划的方法,并给出3种不同的不平衡功率分配方式;提出以相似潮流中无功分布为初值并根据有功潮流相似度决定参数变化范围的无功调整方法。所提算法的有效性用 IEEE 39节点和中国国家电网的算例进行了验证。所提算法收敛性强,能给出与计划值和电网实际情况高度接近的潮流结果,具有良好的推广应用价值。

  10. The behavior of dissolution/passivation and the transformation of passive films during electrocoagulation: Influences of initial pH, Cr(VI) concentration, and alternating pulsed current

    International Nuclear Information System (INIS)

    Highlights: • Initial pH, Cr(VI) and APC could affect the behavior of dissolution/passivation in Fe-EC. • A dissolution/passivation region was constructed with different initial pH-Cr(VI). • The film was rich in Fe and Cr at high Cr(VI), whereas with lots of Fe but negligible of Cr at low Cr(VI). • The film was non-protective at long TAPC, but became more stable and protective at short TAPC. • Behavior of dissolution/passivation and passive film transformation in Fe-EC was elucidated. - Abstract: The passivation behavior of an iron anode for electrocoagulation (EC) was first investigated using response surface methodology (RSM). Tested initial pH range, Cr(VI) concentration and alternating pulsed current (APC) were 4.0 to 8.0, 52 to 520 mg L−1 and 10 to 590 s, respectively. The distance between electrodes was 25 mm, and K2SO4 (1 g L−1) was used as the supporting electrolyte in a 2.5 L EC reactor. Results confirmed that initial pH, Cr(VI) concentration, and APC significantly influence the extent of passivation. Then, based on the interaction effect on passivation behavior between initial pH and Cr(VI) in RSM, a pH-Cr(VI)-dissolution/passivation diagram was constructed with galvanostatic measurements. The diagram showed an optimal dissolution region for EC operation. This optimum was characterized by a reasonable final pH for extended precipitation and little passivation. Results of the cyclic voltammetry and X-ray photoelectron spectroscopy revealed a significant difference in the composition and stability of oxide films in the region with more pronounced passivation. Interestingly, the APC had both positive and negative effect on the passivation behavior. Long period of APC (TAPC = 590 s) produced a non-protective film, which favored the Fe0 dissolution. However, a more stable and protective passive film with a uniform structure of Fe and Cr oxides was formed by short TAPC (10 s). Based on the above results, this study elucidated the behavior of

  11. Speed Control of Bldc Motor Drive By Using Pid Controllers

    Directory of Open Access Journals (Sweden)

    Y.Narendra Kumar,

    2014-04-01

    Full Text Available This paper mainly deals with the Brushless DC (BLDC motor speed driving systems have sprouted in various small scale and large scale applications like automobile industries, domestic appliances etc. This leads to the development in Brushless DC motor (BLDCM. The usage of BLDC Motor enhances various performance factors ranging from higher efficiency, higher torque in low-speed range, high power density ,low maintenance and less noise than other motors. The BLDC Motor can act as an alternative for traditional motors like induction and switched reluctance motors. In this paper PID controller is implemented with speed feedback loop and it is observe that torque ripples are minimized. Simulation is carried out using MATLAB / SIMULINK. The results show that the performance of BLDC Motor is quite satisfactory for various loading conditions. Brushless DC motor drives are typically employed in speed controlled applications.

  12. Line start permanent magnet synchronous motors: Challenges and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Hassanpour Isfahani, Arash; Vaez-Zadeh, Sadegh [School of Electrical and Computer Engineering, Faculty of Engineering, University of Tehran, North Kargar Ave., P.O. Box: 14395/515, Tehran (Iran)

    2009-11-15

    Future energy challenges, likewise the environmental crises such as fossil fuel emissions and global warming urge the world to focus on energy saving programs more than ever. An effective way to face these challenges is to improve electric motors efficiency as one of the greatest energy consumption apparatuses in the world. Induction motors constitute, by far, the largest portion of electric motors both in terms of quantity and total power ratings among all electric motors. However, more efficient motor types gradually appear as alternatives. In this paper, line start permanent magnet motors as a powerful candidate with growing market are investigated in some details. The motor opportunities like high efficiency, high power factor and high power density are explored against the challenges associated with this motor including higher cost, extra manufacturing burden and transient and synchronization behaviors. Finally, some concluding comments and remarks are drawn for future research and manufacturing of line start permanent magnet motors. (author)

  13. High Performance Direct Torque Control of Induction Motor Drives Using Space Vector Modulation

    OpenAIRE

    S. Allirani; Jagannathan, V.

    2010-01-01

    This paper presents a simple approach to design and implement Direct Torque Control technique for voltage source inverter fed induction motor drives. The direct torque control is one of the excellent strategies available for torque control of induction machine. It is considered as an alternative to field oriented control technique. The Direct Torque Control scheme is characterized by the absence of PI regulators, co-ordinate transformations, current regulators and pulse width modulated signal...

  14. Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis%基于定子电流法监测无刷直流电动机转子动态偏心的故障模型仿真研究

    Institute of Scientific and Technical Information of China (English)

    赵向阳; 葛文韬

    2011-01-01

    The dynamic eccentricity fault model was implemented and the inductance and flux were resolved based on the finite element method (FEA) on Ansoft/Maxwell. That the simplified fault frequency of monitoring induction motor dynamic eccentricity could be used on brushless DC motor (BLDC) was demonstrated by simulation. The system of brushless DC motor was simulated on Ansoft/Simplorer. In steady state, the Fast Fourier Transform (FFT) analysis was used on the stator current. The simulated model of detecting dynamic eccentricity based on the stator current signature analysis (MCSA) method was investigated and implemented: The frequency to indentify dynamic eccentricity fault, the amplitude of frequency to estimate the dynamic eccentricity severity. Furthermore, the effect of speed pulsation of BLDC operating under steady state was investigated in this article. The results indicate that the severity of dynamic eccentricity fault increase, the amplitude of fault frequency increase.%基于Ansoft/Maxwell设置动态偏心故障,建立求解电机电感和磁链的有限元模型,通过仿真,证明了将感应电机动态偏心故障的特征频率经过简化后,同样适用于无刷直流电动机。基于Ansoft/Simplorer建立无刷直流电动机系统的仿真模型。在电机稳态运行下,对定子电流进行傅里叶分析,研究并建立基于定子电流监测动态偏心故障的仿真模型:动态偏心故障与特征频率的关系、动态偏心故障程度与特征频率幅值的关系。进而研究了无刷直流电动机稳态运行时转速波动对偏心故障监测的影响。仿真结果表明,转子偏心程度加大,特征频率的幅值增加。

  15. Actions to promote energy efficient electric motors. Motors study group

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, A.T. de [Coimbra Univ. (PT). Inst. of Systems and Robotics (ISR)

    1996-10-01

    Motor electricity consumption is influenced by many factors including: motor efficiency, motor speed controls, power supply quality, harmonics, systems oversizing, distribution network, mechanical transmission system, maintenance practices, load management and cycling, and the efficiency of the end-use device (e.g. fan, pump, etc.). Due to their importance, an overview of these factors is presented in this report. This study also describes the electricity use in the industrial and tertiary sectors and the electricity consumption associated with the different types of electric motors systems in the Member States of the European Union, as well as estimated future evolution until 2010. The studies for individual countries were carried out by the different partners of the motors study group at a previous stage. The study has found that there is a lack of accurate information about the motor electricity consumption, installed motor capacity and the motor market in almost all the European Union countries and only some general statistical sources are available. There is little field data, which is mainly available in Denmark, France, Italy and the Netherlands. Due to this lack of primary information, some common assumptions were made, based on the experience of the members of the study group. This lack of end-use characterisation data shows the need for improvement from the point of view of current knowledge. It is therefore recommended that further research is undertaken to arrive at more accurate figures. These could be the basis for a better understanding for motor use in practice and - as a consequence - for a more precise appraisal of potentials and barriers to energy efficiency. (orig.)

  16. Alternative security

    International Nuclear Information System (INIS)

    This book contains the following chapters: The Military and Alternative Security: New Missions for Stable Conventional Security; Technology and Alternative Security: A Cherished Myth Expires; Law and Alternative Security: Toward a Just World Peace; Politics and Alternative Security: Toward a More Democratic, Therefore More Peaceful, World; Economics and Alternative Security: Toward a Peacekeeping International Economy; Psychology and Alternative Security: Needs, Perceptions, and Misperceptions; Religion and Alternative Security: A Prophetic Vision; and Toward Post-Nuclear Global Security: An Overview

  17. 代用燃料汽车技术发展现状及应用前景%Current Development and Application Prospect of Automotive Alternative Fuel Technology

    Institute of Scientific and Technical Information of China (English)

    张宗法

    2012-01-01

    分析了主要代用燃料的类型、特点、存在的问题与应用情况,研究了代用燃料汽车技术的应用现状和发展趋势,讨论了代用燃料汽车应用前景和发展潜力,指出我国汽车应用推广应当走多元化的能源之路。%This paper analyzes the alternative fuel' s main types, characteristics, existing problems and application, researches the application and development tendency of alternative fuel technology. The application prospect and development potential of alternative fuel automobile are discussed in the paper. And then a conclusion is drew that the diversified energy sources must be chosen for vehicle application promotion in China.

  18. Simulation Study on Alternative Current Fault at Inverter Side of Yunnan-Guangdong Ultrahigh Voltage Direct Current Island Operation System%云广直流孤岛系统逆变侧交流故障仿真研究

    Institute of Scientific and Technical Information of China (English)

    刘洪涛; 张勇; 梅勇; 周煜智; 徐政

    2015-01-01

    云广特高压直流孤岛运行时,送端电网短路比和有效惯性常数显著低于联网方式,承受扰动能力较弱。如果逆变侧交流系统发生接地故障导致逆变站换相失败,直流电压和直流功率将大幅降低,引起送端孤岛系统过电压和频率升高。利用 PSCAD/EMTDC 电磁仿真软件,针对云广直流孤岛系统两种典型运行方式,研究了逆变侧交流系统故障对送端孤岛系统的影响。仿真结果表明:逆变侧交流系统故障引起的直流换相失败持续时间越长,整流侧交流系统短路比和有效惯性常数越小,送端孤岛系统受故障影响越严重;云广直流在两种典型孤岛运行方式下,逆变侧交流系统发生故障时,送端孤岛系统都能保持暂态稳定。%Short circuit ratio and effective inertia constant of the sending end grid under island operation mode of Yunnan-Guangdong ultrahigh voltage direct current(UVDC)project is notably lower than that under networking mode which means weak ability to bear turbulence. If commutation of the inverter station fails caused by grounding fault of alternative current (AC)system at the inverter side ,DC voltage and DC power may substantially reduce and cause overvoltage and frequency of the island system at sending end rise. In allusion two typical running modes of Yunnan-Guangdong UVDC island system, PSCAD/EMTDC electromagnetic simulation software was used for studying affect on the island system at sending end by AC system fault at the inverter side. The simulation results indicate that duration time of DC commutation failure is longer caused by AC system fault at the inverter side,short circuit ratio and effective inertia constant at the rectification side is smaller and affect on island system at sending end by the fault is more serious. In addition,under these two typical island op-eration modes,when the AC system at inverter side develops a fault,island system at sending end

  19. Design and control of a superconducting permanent magnet synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Pei, R [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Hong, Z [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Song, J [Huazhong University of Science of Technology, Wuhan 430074 (China); Fang, F [Huazhong University of Science of Technology, Wuhan 430074 (China); Coombs, T A [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2007-07-15

    This paper gives a detailed description of the design of a superconducting permanent magnet synchronous motor. The parameters of the motor have been identified, and the torque equation has been stated. A direct torque control algorithm is introduced and applied to a traditional permanent magnet synchronous motor and the superconducting permanent magnet synchronous motor described in this paper. The motor performance shows that the direct torque control algorithm provides excellent control to the superconducting motor, and guarantees that the magnitude of the operational armature currents is smaller than the value of the critical current of the superconducting tape used for stator winding.

  20. Using the motor to monitor pump conditions

    Energy Technology Data Exchange (ETDEWEB)

    Casada, D. [Oak Ridge National Lab., TN (United States)

    1996-12-01

    When the load of a mechanical device being driven by a motor changes, whether in response to changes in the overall process or changes in the performance of the driven device, the motor inherently responds. For induction motors, the current amplitude and phase angle change as the shaft load changes. By examining the details of these changes in amplitude and phase, load fluctuations of the driven device can be observed. The usefulness of the motor as a transducer to improve the understanding of devices with high torque fluctuations, such as positive displacement compressors and motor-operated valves, has been recognized and demonstrated for a number of years. On such devices as these, the spectrum of the motor current amplitude, phase, or power normally has certain characteristic peaks associated with various load components, such as the piston stroke or gear tooth meshing frequencies. Comparison and trending of the amplitudes of these peaks has been shown to provide some indication of their mechanical condition. For most centrifugal pumps, the load fluctuations are normally low in torque amplitude, and as a result, the motor experiences a correspondingly lower level of load fluctuation. However, both laboratory and field test data have demonstrated that the motor does provide insight into some important pump performance conditions, such as hydraulic stability and pump-to-motor alignment. Comparisons of other dynamic signals, such as vibration and pressure pulsation, to motor data for centrifugal pumps are provided. The effects of inadequate suction head, misalignment, mechanical and hydraulic unbalance on these signals are presented.