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Sample records for linear motor compressor

  1. Analysis of Nonlinear Dynamics in Linear Compressors Driven by Linear Motors

    Chen, Liangyuan

    2018-03-01

    The analysis of dynamic characteristics of the mechatronics system is of great significance for the linear motor design and control. Steady-state nonlinear response characteristics of a linear compressor are investigated theoretically based on the linearized and nonlinear models. First, the influence factors considering the nonlinear gas force load were analyzed. Then, a simple linearized model was set up to analyze the influence on the stroke and resonance frequency. Finally, the nonlinear model was set up to analyze the effects of piston mass, spring stiffness, driving force as an example of design parameter variation. The simulating results show that the stroke can be obtained by adjusting the excitation amplitude, frequency and other adjustments, the equilibrium position can be adjusted by adjusting the DC input, and to make the more efficient operation, the operating frequency must always equal to the resonance frequency.

  2. A review of linear compressors for refrigeration

    Liang, Kun

    2017-01-01

    Linear compressor has no crank mechanism compared with conventional reciprocating compressor. This allows higher efficiency, oil-free operation, lower cost and smaller size when linear compressors are used for vapour compression refrigeration (VCR) system. Typically, a linear compressor consists of a linear motor (connected to a piston) and suspension springs, operated at resonant frequency. This paper presents a review of linear compressors for refrigeration system. Different designs and mod...

  3. Performance test of 100 W linear compressor

    Ko, J; Ko, D. Y.; Park, S. J.; Kim, H. B.; Hong, Y. J.; Yeom, H. K. [Korea Institute of Machinery and Materials, Daejeon(Korea, Republic of)

    2013-09-15

    In this paper, we present test results of developed 100 W class linear compressor for Stirling-type pulse tube refrigerator. The fabricated linear compressor has dual-opposed configuration, free piston and moving magnet type linear motor. Power transfer, efficiency and required pressure waveform are predicted with designed and measured specifications. In experiments, room temperature test with flow impedance is conducted to evaluate performance of developed linear compressor. Flow impedance is loaded to compressor with metering valve for flow resistance, inertance tube for flow inertance and buffer volumes for flow compliance. Several operating parameters such as input voltage, current, piston displacement and pressure wave are measured for various operating frequency and fixed input current level. Behaviors of dynamics and performance of linear compressor as varying flow impedance are discussed with measured experimental results. The developed linear compressor shows 124 W of input power, 86 % of motor efficiency and 60 % of compressor efficiency at its resonant operating condition.

  4. Modelling and measurement of a moving magnet linear compressor performance

    Liang, Kun; Stone, Richard; Davies, Gareth; Dadd, Mike; Bailey, Paul

    2014-01-01

    A novel moving magnet linear compressor with clearance seals and flexure bearings has been designed and constructed. It is suitable for a refrigeration system with a compact heat exchanger, such as would be needed for CPU cooling. The performance of the compressor has been experimentally evaluated with nitrogen and a mathematical model has been developed to evaluate the performance of the linear compressor. The results from the compressor model and the measurements have been compared in terms of cylinder pressure, the ‘P–V’ loop, stroke, mass flow rate and shaft power. The cylinder pressure was not measured directly but was derived from the compressor dynamics and the motor magnetic force characteristics. The comparisons indicate that the compressor model is well validated and can be used to study the performance of this type of compressor, to help with design optimization and the identification of key parameters affecting the system transients. The electrical and thermodynamic losses were also investigated, particularly for the design point (stroke of 13 mm and pressure ratio of 3.0), since a full understanding of these can lead to an increase in compressor efficiency. - Highlights: • Model predictions of the performance of a novel moving magnet linear compressor. • Prototype linear compressor performance measurements using nitrogen. • Reconstruction of P–V loops using a model of the dynamics and electromagnetics. • Close agreement between the model and measurements for the P–V loops. • The design point motor efficiency was 74%, with potential improvements identified

  5. The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

    Ackermann, R. A.

    1985-01-01

    The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

  6. CFD analysis of linear compressors considering load conditions

    Bae, Sanghyun; Oh, Wonsik

    2017-08-01

    This paper is a study on computational fluid dynamics (CFD) analysis of linear compressor considering load conditions. In the conventional CFD analysis of the linear compressor, the load condition was not considered in the behaviour of the piston. In some papers, behaviour of piston is assumed as sinusoidal motion provided by user defined function (UDF). In the reciprocating type compressor, the stroke of the piston is restrained by the rod, while the stroke of the linear compressor is not restrained, and the stroke changes depending on the load condition. The greater the pressure difference between the discharge refrigerant and the suction refrigerant, the more the centre point of the stroke is pushed backward. And the behaviour of the piston is not a complete sine wave. For this reason, when the load condition changes in the CFD analysis of the linear compressor, it may happen that the ANSYS code is changed or unfortunately the modelling is changed. In addition, a separate analysis or calculation is required to find a stroke that meets the load condition, which may contain errors. In this study, the coupled mechanical equations and electrical equations are solved using the UDF, and the behaviour of the piston is solved considering the pressure difference across the piston. Using the above method, the stroke of the piston with respect to the motor specification of the analytical model can be calculated according to the input voltage, and the piston behaviour can be realized considering the thrust amount due to the pressure difference.

  7. Compressor Surge Control Design Using Linear Matrix Inequality Approach

    Uddin, Nur; Gravdahl, Jan Tommy

    2017-01-01

    A novel design for active compressor surge control system (ASCS) using linear matrix inequality (LMI) approach is presented and including a case study on piston-actuated active compressor surge control system (PAASCS). The non-linear system dynamics of the PAASCS is transformed into linear parameter varying (LPV) system dynamics. The system parameters are varying as a function of the compressor performance curve slope. A compressor surge stabilization problem is then formulated as a LMI probl...

  8. A CFD study of Screw Compressor Motor Cooling Analysis

    Branch, S.

    2017-08-01

    Screw compressors use electric motors to drive the male screw rotor. They are cooled by the suction refrigerant vapor that flows around the motor. The thermal conditions of the motor can dramatically influence the performance and reliability of the compressor. The more optimized this flow path is, the better the motor performance. For that reason it is important to understand the flow characteristics around the motor and the motor temperatures. Computational fluid dynamics (CFD) can be used to provide a detailed analysis of the refrigerant’s flow behavior and motor temperatures to identify the undesirable hot spots in the motor. CFD analysis can be used further to optimize the flow path and determine the reduction of hot spots and cooling effect. This study compares the CFD solutions of a motor cooling model to a motor installed with thermocouples measured in the lab. The compressor considered for this study is an R134a screw compressor. The CFD simulation of the motor consists of a detailed breakdown of the stator and rotor components. Orthotropic thermal conductivity material properties are used to represent the simplified motor geometry. In addition, the analysis includes the motor casings of the compressor to draw heat away from the motor by conduction. The study will look at different operating conditions and motor speeds. Finally, the CFD study will investigate the predicted motor temperature change by varying the vapor mass flow rates and motor speed. Recommendations for CFD modeling of such intricate heat transfer phenomenon have thus been proposed.

  9. Handbook on linear motor application

    1988-10-01

    This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.

  10. Linear motor coil assembly and linear motor

    2009-01-01

    An ironless linear motor (5) comprising a magnet track (53) and a coil assembly (50) operating in cooperation with said magnet track (53) and having a plurality of concentrated multi-turn coils (31 a-f, 41 a-d, 51 a-k), wherein the end windings (31E) of the coils (31 a-f, 41 a-e) are substantially

  11. Air Compressor Driving with Synchronous Motors at Optimal Parameters

    Iuliu Petrica

    2010-10-01

    Full Text Available In this paper a method of optimal compensation of the reactive load by the synchronous motors, driving the air compressors, used in mining enterprises is presented, taking into account that in this case, the great majority of the equipment (compressors, pumps are generally working a constant load.

  12. Insulation system in an integrated motor compressor

    Sihvo, V.

    2010-07-01

    A high-speed and high-voltage solid-rotor induction machine provides beneficial features for natural gas compressor technology. The mechanical robustness of the machine enables its use in an integrated motor-compressor. The technology uses a centrifugal compressor, which is mounted on the same shaft with the high-speed electrical machine driving it. No gearbox is needed as the speed is determined by the frequency converter. The cooling is provided by the process gas, which flows through the motor and is capable of transferring the heat away from the motor. The technology has been used in the compressors in the natural gas supply chain in the central Europe. New areas of application include natural gas compressors working at the wellheads of the subsea gas reservoir. A key challenge for the design of such a motor is the resistance of the stator insulation to the raw natural gas from the well. The gas contains water and heavy hydrocarbon compounds and it is far harsher than the sales gas in the natural gas supply network. The objective of this doctoral thesis is to discuss the resistance of the insulation to the raw natural gas and the phenomena degrading the insulation. The presence of partial discharges is analyzed in this doctoral dissertation. The breakdown voltage of the gas is measured as a function of pressure and gap distance. The partial discharge activity is measured on small samples representing the windings of the machine. The electrical field behavior is also modeled by finite element methods. Based on the measurements it has been concluded that the discharges are expected to disappear at gas pressures above 4 - 5 bar. The disappearance of discharges is caused by the breakdown strength of the gas, which increases as the pressure increases. Based on the finite element analysis, the physical length of a discharge seen in the PD measurements at atmospheric pressure was approximated to be 40 - 120 mum. The chemical aging of the insulation when exposed to raw

  13. Linear induction motor

    Barkman, W.E.; Adams, W.Q.; Berrier, B.R.

    1978-01-01

    A linear induction motor has been operated on a test bed with a feedback pulse resolution of 5 nm (0.2 μin). Slewing tests with this slide drive have shown positioning errors less than or equal to 33 nm (1.3 μin) at feedrates between 0 and 25.4 mm/min (0-1 ipm). A 0.86-m (34-in)-stroke linear motor is being investigated, using the SPACO machine as a test bed. Initial results were encouraging, and work is continuing to optimize the servosystem compensation

  14. Electrodynamic linear motor

    Munehiro, H

    1980-05-29

    When driving the carriage of a printer through a rotating motor, there are problems regarding the limited accuracy of the carriage position due to rotation or contraction and ageing of the cable. In order to solve the problem, a direct drive system was proposed, in which the printer carriage is driven by a linear motor. If one wants to keep the motor circuit of such a motor compact, then the magnetic flux density in the air gap must be reduced or the motor travel must be reduced. It is the purpose of this invention to create an electrodynamic linear motor, which on the one hand is compact and light and on the other hand has a relatively high constant force over a large travel. The invention is characterised by the fact that magnetic fields of alternating polarity are generated at equal intervals in the magnetic field, and that the coil arrangement has 2 adjacent coils, whose size corresponds to half the length of each magnetic pole. A logic circuit is provided to select one of the two coils and to determine the direction of the current depending on the signals of a magnetic field sensor on the coil arrangement.

  15. Linear motor driven Stirling coolers for military and commercial applications

    Berry, R.

    1992-01-01

    This paper discusses the design and performance of a miniature, closed cycle, split stirling, cryogenic cooler that provides 1 watt of cooling at 80 K. The compressor uses two opposed linear motors to drive opposed pistons and the expander uses a pneumatically driven displacer. A single electronics module and compressor has been developed to drive three different expanders that have nominal cold cylinder diameters of 5, 8 and 13 mm

  16. Performance Characteristics of a Refrigerator-Freezer with Parallel Evaporators using a Linear Compressor

    Min, Byungchae; Song, Sangjin; Noh, Kiyoul; Kim, Geonwoo; Yoon, Teaseung; Na, Sangkyung; Song, Sanghoon; Yang, Jangsik; Choi, Gyungmin; Kim, Duckjool

    2016-01-01

    A linear compressor for a domestic refrigerator-freezer has energy saving potential compared with a reciprocating compressor because of a low friction loss and free piston system. A linear compressor can control the piston stroke since it does not have mechanical restriction of piston movement. Therefore, the energy consumption of a domestic refrigerator-freezer using a linear compressor can be reduced by changing the cooling capacity of the compressor. In order to investigate the performance...

  17. IEMDC IN-LINE ELECTRIC MOTOR DRIVEN COMPRESSOR

    Michael J. Crowley; Prem N. Bansal

    2004-10-01

    This report contains the final project summary and deliverables required by the award for the development of an In-line Electric Motor Driven Compressor (IEMDC). Extensive work was undertaken during the course of the project to develop the motor and the compressor section of the IEMDC unit. Multiple design iterations were performed to design an electric motor for operation in a natural gas environment and to successfully integrate the motor with a compressor. During the project execution, many challenges were successfully overcome in order to achieve the project goals and to maintain the system design integrity. Some of the challenges included limiting the magnitude of the compressor aerodynamic loading for appropriate sizing of the magnetic bearings, achieving a compact motor rotor size to meet the rotor dynamic requirements of API standards, devising a motor cooling scheme using high pressure natural gas, minimizing the impact of cooling on system efficiency, and balancing the system thrust loads for the magnetic thrust bearing. Design methods that were used on the project included validated state-of-the-art techniques such as finite element analysis and computational fluid dynamics along with the combined expertise of both Curtiss-Wright Electro-Mechanical Corporation and Dresser-Rand Company. One of the most significant areas of work undertaken on the project was the development of the unit configuration for the system. Determining the configuration of the unit was a significant step in achieving integration of the electric motor into a totally enclosed compression system. Product review of the IEMDC unit configuration was performed during the course of the development process; this led to an alternate design configuration. The alternate configuration is a modular design with the electric motor and compressor section each being primarily contained in its own pressure containing case. This new concept resolved the previous conflict between the aerodynamic flow

  18. Chicane and wiggler based bunch compressors for future linear colliders

    Raubenheimer, T.O.; Emma, P.; Kheifets, S.

    1993-05-01

    In this paper, we discuss bunch compressors for future linear colliders. In the past, the bunch compression optics has been based upon achromatic cells using strong sextupoles to correct the dispersive and betatron chromaticity. To preserve the very small emittances required in most future collider designs, these schemes tend to have very tight alignment tolerances. Here, we describe bunch compressors based upon magnetic chicanes or wigglers which do need sextupoles to correct the chromatic emittance dilution. The dispersive chromaticity cancels naturally and the betatron chromaticity is not a significant source of emittance dilution. Thus, these schemes allow for substantially reduced alignment tolerances. Finally, we present a detailed design for the NLC linear collider

  19. Reciprocating linear motor

    Goldowsky, Michael P. (Inventor)

    1987-01-01

    A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.

  20. Dual capacity compressor with reversible motor and controls arrangement therefor

    Sisk, Francis J.

    1980-12-02

    A hermetic reciprocating compressor such as may be used in heat pump applications is provided for dual capacity operation by providing the crankpin of the crankshaft with an eccentric ring rotatably mounted thereon, and with the end of the connecting rod opposite the piston encompassing the outer circumference of the eccentric ring, with means limiting the rotation of the eccentric ring upon the crankpin between one end point and an opposite angularly displaced end point to provide different values of eccentricity depending upon which end point the eccentric ring is rotated to upon the crankpin, and a reversible motor in the hermetic shell of the compressor for rotating the crankshaft, the motor operating in one direction effecting the angular displacement of the eccentric ring relative to the crankpin to the one end point, and in the opposite direction effecting the angular displacement of the eccentric ring relative to the crankpin to the opposite end point, this arrangement automatically giving different stroke lengths depending upon the direction of motor rotation. The mechanical structure of the arrangement may take various forms including at least one in which any impact of reversal is reduced by utilizing lubricant passages and chambers at the interface area of the crankpin and eccentric ring to provide a dashpot effect. In the main intended application of the arrangement according to the invention, that is, in a refrigerating or air conditioning system, it is desirable to insure a delay during reversal of the direction of compressor operation. A control arrangement is provided in which the control system controls the direction of motor operation in accordance with temperature conditions, the system including control means for effecting operation in a low capacity direction or alternatively in a high capacity direction in response to one set, and another set, respectively, of temperature conditions and with timer means delaying a restart of the compressor

  1. Experimental studies on twin PTCs driven by dual piston head linear compressor

    Gour, Abhay S.; Joy, Joewin; Sagar, Pankaj; Sudharshan, H.; Mallappa, A.; Karunanithi, R.; Jacob, S.

    2017-02-01

    An experimental study on pulse tube cryocooler is presented with a twin pulse tube configuration. The study is conducted with a dual piston head linear compressor design which is developed indigenously. The two identical pulse tube cryocoolers are operated by a single linear motor which generates 1800 out of phase dual pressure waves. The advantages of the configuration being the reduction in fabrication cost and the increased cooling power. The compressor is driven at a frequency of 48 Hz using indigenously developed PWM based power supply. The CFD study of pulse tube cryocooler is discussed along with the experimental cool down results. A detailed experimental and FEM based studies on the fabrication procedure of heat exchangers is conducted to ensure better heat transfer in the same.

  2. Vibration analysis of the synchronous motor of a propane compressor

    Nogueira, D.; Rangel Junior, J. de S. [Petroleo Brasileiro S.A. - PETROBRAS, Rio de Janeiro, RJ (Brazil)], Emails: diananogueira@petrobras.com.br, joilson_jr@petrobras.com.br; Moreira, R.G. [Petroleo Brasileiro S.A. - PETROBRAS, Cabiunas, RJ (Brazil)], E-mail: ricgmoreira@petrobras.com.br

    2010-07-01

    This paper aims at describing the Analysis of a synchronous electric motor which presented high vibration levels (shaft displacement and bearing housing vibration) during the commissioning process, as well as propose the best practices for the solution of vibration problems in similar situations. This motor belongs to the propane centrifugal compressor installed at a Gas Compression Station. The methodology used in this study conducted an investigation of the problems presented in the motor through the execution of many types of tests and the analysis of the results. The main evaluations were performed, such as the vibration analysis and the rotor dynamic analysis. The electric motor was shipped back to the manufacturer's shop, where the manufacturer made certain modifications to the motor structure so as to improve the structure stiffness, such as the improvement of the support and the increase of the thickness of the structural plates. In addition to that, the dynamic balancing of the rotating set was checked. Finally, the excitation at a critical speed close to the rated speed was found after Rotor Dynamics Analysis was performed again, because of the increase in bearing clearances. The bearing shells were replaced so as to increase the separation margin between these frequencies. In order to verify the final condition of the motor, the manufacturer repeated the standard tests - FAT (Factory Acceptance Tests) - according to internal procedure and international standards. As a result of this work, it was possible to conclude that there was a significant increase in the vibration levels due to unbalance conditions. It was also possible to conclude that there are close relationships between high vibration levels and unbalance conditions, as well as between high vibration levels and the stiffness of the system and its support. Certain points of attention related to the manufacturing process of the motor compressor are described at the end of this paper, based

  3. Development of 1 kW Stirling cryocooler using a linear compressor

    Ko, J; Kim, H; Hong, Y J; Yeom, H; In, S; Park, S J

    2015-01-01

    Cryogenic cooling systems for HTS electric power devices require a reliable and efficient high-capacity cryocooler. A Striling cryocooler with a linear compressor can be a good candidate. It has advantages of low vibration and long maintenance cycle compared with a kinematic-driven Stirling cryocooler. In this study, we developed a dual-opposed linear compressor of 12 kW electric input power with two 6 kW linear motors. Electrical performance of the fabricated linear compressor is verified by experimental measurement of thrust constant. The developed Stirling cryocooler has a gamma-type configuration. The piston and displacer are supported with a flexure spring. A slit-type heat exchanger is adopted for the cold and warm-end, and the generated heat is rejected by cooling water. In the cooling performance test, waveforms of voltage, current, displacement and pressure are obtained and their amplitude and phase difference are analysed. The developed cryocooler reaches 47.8 K within 23.4 min. with no-load. Heat load tests shows a cooling capacity of 440 W at 78.1 K with 6.45 kW of electric input power and 19.4 of % Carnot COP. (paper)

  4. Linear Gain for the Microbunching Instability in an RF Compressor

    Venturini, M.; Migliorati, M.; Ronsivalle, C.; Vaccarezza, C.

    2009-01-01

    Velocity (or rf) compression has been suggested as a technique for bunch compression complementary to the more established technique involving magnetic chicanes and represents an important research item being investigated at the SPARC test facility. One of the aspects of this technique still not sufficiently understood is its possible impact on the microbunching instability. The purpose of this report is to present the analytical framework for investigating this instability in rf compressors. We use methods similar to those successfully applied to magnetic compressors and derive some integral equations yielding the gain for the instability in linear approximation. The focus here is on the derivation of the relevant equations. Although examples of solutions to these equations are provided we defer a more comprehensive discussion of their implication to a future report. The present study is part of a larger effort for a more comprehensive investigation that eventually will include macroparticle simulations and experiments.

  5. Miniature high speed compressor having embedded permanent magnet motor

    Zhou, Lei (Inventor); Zheng, Liping (Inventor); Chow, Louis (Inventor); Kapat, Jayanta S. (Inventor); Wu, Thomas X. (Inventor); Kota, Krishna M. (Inventor); Li, Xiaoyi (Inventor); Acharya, Dipjyoti (Inventor)

    2011-01-01

    A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing supports.

  6. Reciprocating Linear Electric Motor

    Goldowsky, M. P.

    1984-01-01

    Features include structural simplicity and good force/displacement characteristics. Reciprocating motor has simple, rugged construction, relatively low reciprocating weight, improved power delivery, and improved force control. Wear reduced by use of magnetic bearings. Intended to provide drivers for long-lived Stirling-cycle cryogenic refrigerators, concept has less exotic applications, such as fuel pumps.

  7. Hermetically Sealed Compressor

    Holtzapple, Mark T.

    1994-01-01

    Proposed hermetically sealed pump compresses fluid to pressure up to 4,000 atm (400 MPa). Pump employs linear electric motor instead of rotary motor to avoid need for leakage-prone rotary seals. In addition, linear-motor-powered pump would not require packings to seal its piston. Concept thus eliminates major cause of friction and wear. Pump is double-ended diaphragm-type compressor. All moving parts sealed within compressor housing.

  8. Numerical investigation of refrigeration machine compressor operation considering single-phase electric motor dynamic characteristics

    Baidak, Y.; Smyk, V.

    2017-08-01

    Using as the base the differential equations system which was presented in relative units for generalized electric motor of hermetic refrigeration compressor, mathematical model of the software for dynamic performance calculation of refrigeration machine compressors drive low-power asynchronous motors was developed. Performed on its ground calculations of the basic model of two-phase electric motor drive of hermetic compressor and the proposed newly developed model of the motor with single-phase stator winding, which is an alternative to the industrial motor winding, have confirmed the benefits of the motor with innovative stator winding over the base engine. Given calculations of the dynamic characteristics of compressor drive motor have permitted to determine the value of electromagnetic torque swinging for coordinating compressor and motor mechanical characteristics, and for taking them into consideration in choosing compressor elements construction materials. Developed and used in the process of investigation of refrigeration compressor drive asynchronous single-phase motor mathematical and software can be considered as an element of computer-aided design system for design of the aggregate of refrigeration compression unit refrigerating machine.

  9. Linear Motor With Air Slide

    Johnson, Bruce G.; Gerver, Michael J.; Hawkey, Timothy J.; Fenn, Ralph C.

    1993-01-01

    Improved linear actuator comprises air slide and linear electric motor. Unit exhibits low friction, low backlash, and more nearly even acceleration. Used in machinery in which positions, velocities, and accelerations must be carefully controlled and/or vibrations must be suppressed.

  10. Noise analysis of fluid-valve system in a linear compressor using CAE

    Lee, Jun Ho; Jeong, Weui Bong; Kim, Dang Ju

    2009-01-01

    A linear compressor in a refrigerator uses piston motion to transfer refrigerant so its efficiency is higher than a previous reciprocal compressor. Because of interaction between refrigerant and valves system in the linear compressor, however, noise has been a main issue. In spite of doing many experimental researches, there is no way to rightly predict the noise. In order to solve this limitation, the CAE analysis is applied. For giving credit to these computational data, all of the data are experimentally validated.

  11. Segmented rail linear induction motor

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  12. Linear Synchronous Motor Repeatability Tests

    Ward, C.R.

    2002-01-01

    A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility

  13. DEVELOPMENT OF A LINEAR COMPRESSOR FOR AIR CONDITIONERS AND HEAT PUMPS

    The report discusses the design, building, testing, and delivering to the Environmental Protection Agency of a linear compressor for operation in a 3.0- ton (10.5 kW) residential air-conditioning and heat pumping system. The compressor design evolved from a linear resonant piston...

  14. Available pressure amplitude of linear compressor based on phasor triangle model

    Duan, C. X.; Jiang, X.; Zhi, X. Q.; You, X. K.; Qiu, L. M.

    2017-12-01

    The linear compressor for cryocoolers possess the advantages of long-life operation, high efficiency, low vibration and compact structure. It is significant to study the match mechanisms between the compressor and the cold finger, which determines the working efficiency of the cryocooler. However, the output characteristics of linear compressor are complicated since it is affected by many interacting parameters. The existing matching methods are simplified and mainly focus on the compressor efficiency and output acoustic power, while neglecting the important output parameter of pressure amplitude. In this study, a phasor triangle model basing on analyzing the forces of the piston is proposed. It can be used to predict not only the output acoustic power, the efficiency, but also the pressure amplitude of the linear compressor. Calculated results agree well with the measurement results of the experiment. By this phasor triangle model, the theoretical maximum output pressure amplitude of the linear compressor can be calculated simply based on a known charging pressure and operating frequency. Compared with the mechanical and electrical model of the linear compressor, the new model can provide an intuitionistic understanding on the match mechanism with faster computational process. The model can also explain the experimental phenomenon of the proportional relationship between the output pressure amplitude and the piston displacement in experiments. By further model analysis, such phenomenon is confirmed as an expression of the unmatched design of the compressor. The phasor triangle model may provide an alternative method for the compressor design and matching with the cold finger.

  15. Optimization analysis of the motor cooling method in semi-closed single screw refrigeration compressor

    Wang, Z. L.; Shen, Y. F.; Wang, Z. B.; Wang, J.

    2017-08-01

    Semi-closed single screw refrigeration compressors (SSRC) are widely used in refrigeration and air conditioning systems owing to the advantages of simple structure, balanced forces on the rotor, high volumetric efficiency and so on. In semi-closed SSRCs, motor is often cooled by suction gas or injected refrigerant liquid. Motor cooling method will changes the suction gas temperature, this to a certain extent, is an important factor influencing the thermal dynamic performance of a compressor. Thus the effects of motor cooling method on the performance of the compressor must be studied. In this paper mathematical models of motor cooling process by using these two methods were established. Influences of motor cooling parameters such as suction gas temperature, suction gas quantity, temperature of the injected refrigerant liquid and quantity of the injected refrigerant liquid on the thermal dynamic performance of the compressor were analyzed. The performances of the compressor using these two kinds of motor cooling methods were compared. The motor cooling capacity of the injected refrigerant liquid is proved to be better than the suction gas. All analysis results obtained can be useful for optimum design of the motor cooling process to improve the efficiency and the energy efficiency of the compressor.

  16. Compressor motor for air conditioners realizing high efficiency and low cost; Kokoritsu tei cost wo jitsugenshita eakonyo asshukuki motor

    Inaba, Y.; Kawamura, K.; Imazawa, K. [Toshiba Corp., Tokyo (Japan)

    2000-01-01

    The compressor motor accounts for most of the consumption of electric power in an air conditioner. To promote energy-saving, Toshiba has been progressively changing the compressor motors in its air conditioners to high-efficiency brushless DC motors. We have now developed a new compressor motor in order to achieve even greater energy-saving. A concentrated winding system was adopted featuring direct winding on the teeth of the stator core, for the first time in the industry. As a result, it was possible to realize a high-efficiency, compact, lightweight, and low-cost motor. Moreover, by constructing a new system for production, we were able to improve productivity and quality. The newly developed motor is expected to contribute to the further diffusion of energy-saving air conditioners. (author)

  17. Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

    Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

    2017-04-01

    A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

  18. Study and Design of a Linear Compressor of Voice-Coil Typ

    VADAN, I.

    2009-06-01

    Full Text Available The paper presents the design and Finite Element (FEM analysis of a Linear compressor of voice coil type (LCVCT. This kind of linear compressor will be used in a refrigerator equipment. It is well-known that the replacing of the rotating compressor from a classical refrigerator by a linear compressor leads to an efficiency improving wit about 5% by avoiding the piston side friction, which is very important because of the huge number of refrigerators in operation world-wide. The linear compressor refrigerator is already commercially available in South Korea, equipped with an electromagnetic (fix coil and moving permanent magnet linear compressor. This paper presents a new type of linear compressor - a voice-coil type (fixed permanent magnet and moving coil. The operation principle is the same as for electrodynamic vibrator or electro-dynamic loud-speaker. The designing with rare earth permanent magnet is not a simple problem, because of the nonlinear characteristic of rare earth magnets. A magneto-static FEM analysis has been performed in order to validate the design methodology proposed in the paper.

  19. A study on two phase flows of linear compressors for the prediction of refrigerant leakage

    Hwang, Il Sun; Lee, Young Lim; Oh, Won Sik; Park, Kyeong Bae

    2015-01-01

    Usage of linear compressors is on the rise due to their high efficiency. In this paper, leakage of a linear compressor has been studied through numerical analysis and experiments. First, nitrogen leakage for a stagnant piston with fixed cylinder pressure as well as for a moving piston with fixed cylinder pressure was analyzed to verify the validity of the two-phase flow analysis model. Next, refrigerant leakage of a linear compressor in operation was finally predicted through 3-dimensional unsteady, two phase flow CFD (Computational fluid dynamics). According to the research results, the numerical analyses for the fixed cylinder pressure models were in good agreement with the experimental results. The refrigerant leakage of the linear compressor in operation mainly occurred through the oil exit and the leakage became negligible after about 0.4s following operation where the leakage became lower than 2.0x10 -4 kg/s.

  20. Ultrasonic Linear Motor with Two Independent Vibrations

    Muneishi, Takeshi; Tomikawa, Yoshiro

    2004-09-01

    We propose a new structure of an ultrasonic linear motor in order to solve the problems of high-power ultrasonic linear motors that drive the XY-stage for electron beam equipment and to expand the application fields of the motor. We pay special attention to the following three points: (1) the vibration in two directions of the ultrasonic linear motor should not influence mutually each other, (2) the vibration in two directions should be divided into the stage traveling direction and the pressing direction of the ultrasonic linear motor, and (3) the rigidity of the stage traveling direction of the ultrasonic linear motor should be increased. As a result, the supporting method of ultrasonic linear motors is simplified. The efficiency of the motor is improved and temperature rise is reduced. The stage position drift is also improved.

  1. Development of a linear compressor for compact 2 K Gifford- McMahon cryocoolers

    Hiratsuka, Y

    2015-01-01

    Recently, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed at Sumitomo Heavy Industries, Ltd. (SHI) [1, 2]. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design temperature targets of the first and the second stages to 1 W and 20 mW of heat load at 60 K and 2.3 K, respectively. Although optimization of the internal components is one way to miniaturize the volume of the compressor unit, major design changes are required because the volume of the adsorber and the oil separator is almost the same as the volume of the compressor capsule. Thus, one approach is to develop a non-lubricated compressor, such as a valved linear compressor. An experimental unit of a valved linear compressor was designed and built, and preliminary experiments were conducted. Under no-load condition, a low temperature of 2.19 K has been achieved. With 1 W and 14 mW heat load, the temperature is 48 K at the first stage and 2.3 K at the second stage, with an input power of about 1.2 KW. The detailed experimental results will be discussed in this paper. (paper)

  2. An efficient linear power generator - Linear motor for oscillating piston machines; Effizienter Lineargenerator / Linearmotor fuer Kolbenmaschine - Schlussbericht

    Lindegger, M.

    2008-07-01

    When an oscillating piston interacts with an electrical generator or motor, it is obvious that the electrical machine should also have linear motion, eliminating the disadvantage of a crankshaft. This work has two parts: construction of an efficient linear generator for a Stirling engine with a free piston and a theoretical study of the efficiency of linear motors for driving compressors. The Stirling engine and the linear generator have a continuous power of 1.3 kW{sub el}. With thermal peak power the planned 1.5 kW{sub el} are attained. The Project 'Stirling Free Piston Generator' for cogeneration will continue. Smaller linear motors with permanent magnets function without electronic control from single-phase AC net. The theoretical study shows how linear motors can be led out by linking the electric vector diagram with the pressure-volume diagram of the compressor. At a power level exceeding a few kW, a three-phase system with power electronics is more suitable. The frequency of oscillation is variable and lower than 50 Hz. The efficiency of the simulated linear motors lies in the range of efficiency class EFF1 of standard motors. The very high efficiencies of rotating motors with permanent magnets are not attained. The combination of the linear motor with an optimised thermal process leads to advantages regarding the efficiency. If a heat pump with linear drive system can operate with hot lubricating oil the losses in the heat exchangers are reduced. The Competence Center for Thermal Machines at Lucerne University of Applied Sciences and Arts shows great interest to pursue the project of a linear heat pump for small temperature differences. (author)

  3. Simulation of linear Switched Reluctance Motor drives

    Garcia Amoros, Jordi; Blanqué Molina, Balduino; Andrada Gascón, Pedro

    2011-01-01

    This paper presents a simulation model of linear switched reluctance motor drives. A Matlab-Simulink environment coupled with finite element analysis is used to perform the simulations. Experimental and simulation results for a double sided linear switched motor drive prototype are reported and compared to verify the simulation model.

  4. A linear motor as seismic horizontal vibrator

    Drijkoningen, G.; Veltman, A.; Hendrix, W.H.A.; Brouwer, J.; Hemstede, A.

    2006-01-01

    In this paper we propose to use the concept of linear synchronous motors to act as a seismic shear-wave vibratory source. We show that a linear motor, even with a design that is not focussed on application of seismic surveying, gives seismic records that are convincing and comparable with an

  5. Linear Motor for Drive of Belt Conveyor

    Milan Krasl

    2006-01-01

    Full Text Available This paper introduces a novel approach on the design of a linear motor for drive of belt conveyor (LMBC. The motor is a simple combination of asynchronous motor in plane. The electromagnetic forces is one of the most important parameters of electrical machines. This parameter is necessary for the checking of the design. This paper describes several variants: linear motor with slots in platens, slots in one half of platens and optimization of slots. The electromagnetic force can be found with the help of a Finite Elements Method – based program. For solution was used QuickField program.

  6. Rotor Design for an Efficient Single-Phase Induction Motor for Refrigerator Compressors

    Hyun-Jin Ahn

    2016-03-01

    Full Text Available This article describes a rotor making technology for the production of high-efficiency single-phase induction motors (SPIMs to be used in refrigerator compressors. Rotors can have different aluminum fill factors according to the fabrication method. In order to examine the association between the fill factor and the efficiency of the rotor, we analyzed the distribution of magnetic flux density using the finite element method (FEM. Next, we made prototype rotors by conventional casting methods and by the proposed casting method and compared their fill factors. In addition, SPIMs were made using the rotors, and their efficiencies were measured using a dynamometer. Moreover, the SPIMs were put to use in a compressor, for testing, and for each SPIM the refrigerating capacity of the compressor was measured with a calorimeter. Based on the results of the FEM analysis of the magnetic flux density and the experiments, the reliability and validity of the proposed method were proven.

  7. High efficiency, low frequency linear compressor proposed for Gifford-McMahon and pulse tube cryocoolers

    Höhne, Jens [Pressure Wave Systems GmbH, Häberlstr. 8, 80337 Munich (Germany)

    2014-01-29

    In order to reduce the amount of greenhouse gas emissions, which are most likely the cause of substantial global warming, a reduction of overall energy consumption is crucial. Low frequency Gifford-McMahon and pulse tube cryocoolers are usually powered by a scroll compressor together with a rotary valve. It has been theoretically shown that the efficiency losses within the rotary valve can be close to 50%{sup 1}. In order to eliminate these losses we propose to use a low frequency linear compressor, which directly generates the pressure wave without using a rotary valve. First results of this development will be presented.

  8. Comparison of linear synchronous and induction motors

    2004-06-01

    A propulsion prade study was conducted as part of the Colorado Maglev Project of FTA's Urban Maglev Technology Development Program to identify and evaluate prospective linear motor designs that could potentially meet the system performance requiremen...

  9. Linear motor with contactless energy transfer

    2014-01-01

    An integrated electromagnetic energy conversions device is provided that includes a synchronous or brushless linear (SoBL) motor, and a transformer, where the transformer is integrated electromagnetically and topologically with the SoBL motor, where an electromagnetic field orientation of the

  10. Linear Resonance Compressor for Stirling-Type Cryocoolers Activated by Piezoelectric Stack-Type Elements

    Sobol, S; Grossman, G

    2015-01-01

    A novel type of a PZT- based compressor operating at mechanical resonance, suitable for pneumatically-driven Stirling-type cryocoolers was developed theoretically and built practically during this research. A resonance operation at relatively low frequency was achieved by incorporating the piezo ceramics into the moving part, and by reducing the effective piezo stiffness using hydraulic amplification. The detailed concept, analytical model and the test results of the preliminary prototype were reported earlier and presented at ICC17 [2]. A fine agreement between the simulations and experiments spurred development of the current actual compressor designed to drive a miniature Pulse Tube cryocooler, particularly our MTSa model, which operates at 103 Hz and requires an average PV power of 11 W, filling pressure of 40 Bar and a pressure ratio of 1.3. The paper concentrates on design aspects and optimization of the governing parameters. The small stroke to diameter ratio (about 1:10) allows for the use of a composite diaphragm instead of a clearance-seal piston. The motivation is to create an adequate separation between the working fluid and the buffer gas of the compressor, thus preventing possible contamination in the cryocooler. Providing efficiency and power density similar to those of conventional linear compressors, the piezo compressor may serve as a good alternative for cryogenic applications requiring extreme reliability and absence of magnetic field interference. (paper)

  11. A linear magnetic motor and generator

    Studer, P. A.

    1980-01-01

    In linear magnetic motor and generator suitable for remote and hostile environments, magnetic forces drive reciprocating shaft along its axis. Actuator shaft is located in center of cylindrical body and may be supported by either contacting or noncontacting bearings. When device operates as bidirectional motor, drive coil selectively adds and subtracts magnetic flux to and from flux paths, producing forces that drive actuator along axis. When actuator is driven by external reciprocating engine, device becomes ac generator.

  12. Linear ultrasonic motor for absolute gravimeter.

    Jian, Yue; Yao, Zhiyuan; Silberschmidt, Vadim V

    2017-05-01

    Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors. After that, an effect of tangential and normal rigidity of the clamping components on mechanical output is studied. It is followed by discussion of a new clamping method with sufficient tangential rigidity and a capability to facilitate pre-load. Additionally, a prototype of the motor with the proposed clamping method was fabricated and the performance tests in vertical direction were implemented. Experimental results show that the suggested motor has structural stability and high dynamic performance, such as no-load speed of 1.4m/s and maximal thrust of 43N, meeting the requirements for absolute gravimeters. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Linear Parameter Varying Control of Induction Motors

    Trangbæk, Klaus

    The subject of this thesis is the development of linear parameter varying (LPV) controllers and observers for control of induction motors. The induction motor is one of the most common machines in industrial applications. Being a highly nonlinear system, it poses challenging control problems...... for high performance applications. This thesis demonstrates how LPV control theory provides a systematic way to achieve good performance for these problems. The main contributions of this thesis are the application of the LPV control theory to induction motor control as well as various contributions...

  14. Sensorless control of interior permanent-magnet synchronous motors with compressor load

    Huang, Shoudao; Gao, Jian; Xiao, Lei

    2013-01-01

    This paper analyzes the mathematical model of the interior permanent-magnet synchronous motors (IPMSM). Through the mathematical deformation, the paper proposes the new sensorless method based on sliding mode observer for a IPMSM. The model is only associated with the q-axis inductance, and without...... the d-axis inductance. Dual filter is set series to extract the electromotive force information, and then filter phase shift is measured real-time at different speeds for angle compensation. An I-F strategy is adopted to start the IPMSM with compressor load. Finally, the experimental proves the validity...

  15. A beam scraper using a linear motor

    Beadle, E.R.; Rodger, E.S.; Thern, R.E.

    1989-01-01

    A beam scraper using a linear motor drive has been developed for use in the AGS at Brookhaven National Laboratory. The device is used to measure beam size by moving a target to a predetermined location and measuring the intercepted beam with nearby loss monitors or by noting the decrease in the circulating beam current. This device has excellent vacuum characteristics, as the motor and sensor coils are outside the vacuum, coupled magnetically to the moving parts which, are inside. There are no bellows or dynamic seals required. The position-time profile is controlled by a closed-loop servo system which uses position feedback. 2 refs., 4 figs

  16. Numerical study of corner separation in a linear compressor cascade using various turbulence models

    Liu Yangwei

    2016-06-01

    Full Text Available Three-dimensional corner separation is a common phenomenon that significantly affects compressor performance. Turbulence model is still a weakness for RANS method on predicting corner separation flow accurately. In the present study, numerical study of corner separation in a linear highly loaded prescribed velocity distribution (PVD compressor cascade has been investigated using seven frequently used turbulence models. The seven turbulence models include Spalart–Allmaras model, standard k–ɛ model, realizable k–ɛ model, standard k–ω model, shear stress transport k–ω model, v2–f model and Reynolds stress model. The results of these turbulence models have been compared and analyzed in detail with available experimental data. It is found the standard k–ɛ model, realizable k–ɛ model, v2–f model and Reynolds stress model can provide reasonable results for predicting three dimensional corner separation in the compressor cascade. The Spalart–Allmaras model, standard k–ω model and shear stress transport k–ω model overestimate corner separation region at incidence of 0°. The turbulence characteristics are discussed and turbulence anisotropy is observed to be stronger in the corner separating region.

  17. Comparison of Linear Induction Motor Theories for the LIMRV and TLRV Motors

    1978-01-01

    The Oberretl, Yamamura, and Mosebach theories of the linear induction motor are described and also applied to predict performance characteristics of the TLRV & LIMRV linear induction motors. The effect of finite motor width and length on performance ...

  18. Linear pneumatic motors – a comparative study

    Deaconescu Tudor

    2017-01-01

    Full Text Available The paper presents a comparative study of the performance of single-acting cylinders, diaphragm cylinders and pneumatic muscles, and offers users information that allows the selection of an optimum technical solution. Such a study was necessary, in view of the numerous papers on pneumatic muscle applications found in literature, that assert the superiority of pneumatic muscles over other pneumatic linear motors in relation to quantities like dimensions, mass, developed force or energy-to-mass ratios, however without offering concrete data.

  19. Bunch Compressor Beamlines for the Tesla and S Band Linear Colliders

    Emma, P

    2003-01-01

    A detailed design for a single stage beam bunch length compressor for both the TESLA and the S-Band Linear Collider (SBLC) is presented. Compression is achieved by introducing an energy-position correlation along the bunch with an rf section at zero-crossing phase followed by a short bending section with energy dependent path length (momentum compaction). The motivation for a wiggler design is presented and many of the critical single bunch tolerances are evaluated. A solenoid based spin rotator is included in the design and transverse emittance tuning elements, diagnostics and tuning methods are described. Bunch length limitations due to second order momentum compaction and sinusoidal rf shape are discussed with options for compensation. Finally, the disadvantages of bunch compression using a 180 sup o arc are discussed.

  20. A seismic vertical vibrator driven by linear synchronous motors

    Noorlandt, R.P.; Drijkoningen, G.G.; Dams, J.; Jenneskens, R.

    2015-01-01

    A linear synchronous motor (LSM) is an electric motor that can produce large controllable forces and is therefore suitable as a driving engine for a seismic vibrator. This motor consists of two independent elements, a magnet track and a coil track, allowing practically unlimited motor displacements.

  1. Experimental Investigation of an Automobile Air-Conditioning System using Integrated Brushless Direct Current Motor Rotary Compressor

    Sukri M.F.

    2016-01-01

    Full Text Available The present study presents an experimental investigation on the effect of condenser air inlet temperature and dimensionless parameter of X on the performance of automobile air-conditioning (AAC system using integrated brushless direct current motor-rotary compressor and electronic expansion valve. The other components of AAC system are from original component of AAC system used for medium size passenger car. The experimental results showed that the increment of the condenser air inlet temperature and X caused an increase in condensing temperature, cooling capacity and compressor work, while decreasing the coefficient of performance (COP. Meanwhile, the evaporating temperature increase with the increment of condenser air inlet temperature, but decrease with decrement of X. In general, AAC system have to work at higher value of X in order to produce more cooling capacity, thereby increment in compressor work also occurs due to energy balance. However, at higher value of X, the COP of the system dropped due to dominant increase in compressor power, as opposed to a rise in cooling capacity. Due to this reason, the best operation of this compressor occurs at X = 4.96 for constant T5 (35ºC, or at T5 = 30ºC for constant X (4.96.

  2. International program on linear electric motors

    Dawson, G.E.; Eastham, A.R.; Parker, J.H.

    1992-05-01

    The International Program on Linear Electric Motors (LEM) was initiated for the purposes of commumication and coordination between various centers of expertise in LEM technology in Germany, Japan and Canada. Furthermore, it was intended to provide assessment and support of the planning of technological developments and for dissemination of information to researchers, service operators and policy makers, and to ensure that full advantage can be taken if opportunities for technology transfer occur. In the process, the program was able to provide closer contacts between researchers, to enhance and encourage collaborative research and development, and to facilitate joint ventures in advanced transportation technologies. Work done under the program is documented, and seminar materials presented by Canadian researchers in Italy, and by Italian researchers at Queen's University in Canada are presented. Five separate abstracts have been prepared for the main body of the report and the seminar materials.

  3. Study of linear induction motor characteristics : the Mosebach model

    1976-05-31

    This report covers the Mosebach theory of the double-sided linear induction motor, starting with the ideallized model and accompanying assumptions, and ending with relations for thrust, airgap power, and motor efficiency. Solutions of the magnetic in...

  4. Study of linear induction motor characteristics : the Oberretl model

    1975-05-30

    The Oberretl theory of the double-sided linear induction motor (LIM) is examined, starting with the idealized model and accompanying assumptions, and ending with relations for predicted thrust, airgap power, and motor efficiency. The effect of varyin...

  5. Quad-copter UAV BLDC Motor Control: Linear v/s non-linear control maps

    Deep Parikh

    2015-08-01

    Full Text Available This paper presents some investigations and comparison of using linear versus non-linear static motor-control maps for the speed control of a BLDC (Brush Less Direct Current motors used in quad-copter UAV (Unmanned Aerial Vehicles. The motor-control map considered here is the inverse of the static map relating motor-speed output to motor-voltage input for a typical out-runner type Brushless DC Motors (BLDCM.  Traditionally, quad-copter BLDC motor speed control uses simple linear motor-control map defined by the motor-constant specification. However, practical BLDC motors show non-linear characteristic, particularly when operated across wide operating speed-range as is commonly required in quad-copter UAV flight operations. In this paper, our investigations to compare performance of linear versus non-linear motor-control maps are presented. The investigations cover simulation-based and experimental study of BLDC motor speed control systems for  quad-copter vehicle available. First the non-linear map relating rotor RPM to motor voltage for quad-copter BLDC motor is obtained experimentally using an optical speed encoder. The performance of the linear versus non-linear motor-control-maps for the speed control are studied. The investigations also cover study of time-responses for various standard test input-signals e.g. step, ramp and pulse inputs, applied as the reference speed-commands. Also, simple 2-degree of freedom test-bed is developed in our laboratory to help test the open-loop and closed-loop experimental investigations. The non-linear motor-control map is found to perform better in BLDC motor speed tracking control performance and thereby helping achieve better quad-copter roll-angle attitude control.

  6. Structural Analysis of the Support System for a Large Compressor Driven by a Synchronous Electric Motor

    Winter, J. R.

    1984-01-01

    For economic reasons, the steam drive for a large compressor was replaced by a large synchronous electric motor. Due to the resulting large increase in mass and because the unit was mounted on a steel frame approximately 18 feet above ground level, it was deemed necessary to determine if a steady state or transient vibration problem existed. There was a definite possibility that a resonant or near resonant condition could be encountered. The ensuing analysis, which led to some structural changes as the analysis proceeded, did not reveal any major steady state vibration problems. However, the analysis did indicate that the system would go through several natural frequencies of the support structure during start-up and shutdown. This led to the development of special start-up and shutdown procedures to minimize the possibility of exciting any of the major structural modes. A coast-down could result in significant support structure and/or equipment damage, especially under certain circumstances. In any event, dynamic field tests verified the major analytical results. The unit has now been operating for over three years without any major vibration problems.

  7. Lithographic linear motor, lithographic apparatus, and device manufacturing method

    2006-01-01

    A linear motor having a high driving force, high efficiency and low normal force comprises two opposed magnet tracks and an armature comprising three open coil sets. The linear motor may be used to drive a stage, such as, for example, a mask or wafer stage, in a lithographic apparatus.

  8. Novel concept for driving the linear compressor of a micro-miniature split Stirling cryogenic cooler

    Maron, V.; Veprik, A.; Finkelstein, L.; Vilenchik, H.; Ziv, I.; Pundak, N.

    2009-05-01

    linear compressor remains the same as compared with the traditional sine wave driver, the voltage and current drawn from the battery pack is essentially free of low frequency ripple (this without use of any kind of filtering) and the overall coefficient of performance of the driver is in excess of 94% over the entire working range of supply voltages. Such a driver free of sine forming PWM stage and have reduced power peaks in all power conversion components.

  9. Impact self-excited vibrations of linear motor

    Zhuravlev, V. Ph.

    2010-08-01

    Impact self-exciting vibration modes in a linear motor of a monorail car are studied. Existence and stability conditions of self-exciting vibrations are found. Ways of avoiding the vibrations are discussed.

  10. Experimental development of an ultrasonic linear motor

    M'Boungui, G

    2010-01-01

    Full Text Available the stator structure. In contrast to traditional travelling wave ultrasonic motors, which require two modes to be driven 90° out of phase, only one amplifier is required to drive the proposed device. A prototype device was characterised experimentally...

  11. Linear stability analysis in a solid-propellant rocket motor

    Kim, K.M.; Kang, K.T.; Yoon, J.K. [Agency for Defense Development, Taejon (Korea, Republic of)

    1995-10-01

    Combustion instability in solid-propellant rocket motors depends on the balance between acoustic energy gains and losses of the system. The objective of this paper is to demonstrate the capability of the program which predicts the standard longitudinal stability using acoustic modes based on linear stability analysis and T-burner test results of propellants. Commercial ANSYS 5.0A program can be used to calculate the acoustic characteristic of a rocket motor. The linear stability prediction was compared with the static firing test results of rocket motors. (author). 11 refs., 17 figs.

  12. Modelling a linear PM motor including magnetic saturation

    Polinder, H.; Slootweg, J.G.; Compter, J.C.; Hoeijmakers, M.J.

    2002-01-01

    The use of linear permanent-magnet (PM) actuators increases in a wide variety of applications because of the high force density, robustness and accuracy. The paper describes the modelling of a linear PM motor applied in, for example, wafer steppers, including magnetic saturation. This is important

  13. Analysis of influence of change of office hours on degree of heating of isolation of puttee of anchor of electric motor of piston compressor

    A.V. Mazur

    2012-12-01

    Full Text Available The article is devoted the question of research of factors which influence on changing of the mode of operations of electric motor of compressor, which in same queue influence on the degree of heating of isolation of winding of anchor ED.

  14. Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

    Coffey, Howard T.

    1993-01-01

    A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.

  15. Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor

    Coffey, H.T.

    1993-10-19

    A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.

  16. Comparative analysis of linear motor geometries for Stirling coolers

    R, Rajesh V.; Kuzhiveli, Biju T.

    2017-12-01

    Compared to rotary motor driven Stirling coolers, linear motor coolers are characterized by small volume and long life, making them more suitable for space and military applications. The motor design and operational characteristics have a direct effect on the operation of the cooler. In this perspective, ample scope exists in understanding the behavioural description of linear motor systems. In the present work, the authors compare and analyze different moving magnet linear motor geometries to finalize the most favourable one for Stirling coolers. The required axial force in the linear motors is generated by the interaction of magnetic fields of a current carrying coil and that of a permanent magnet. The compact size, commercial availability of permanent magnets and low weight requirement of the system are quite a few constraints for the design. The finite element analysis performed using Maxwell software serves as the basic tool to analyze the magnet movement, flux distribution in the air gap and the magnetic saturation levels on the core. A number of material combinations are investigated for core before finalizing the design. The effect of varying the core geometry on the flux produced in the air gap is also analyzed. The electromagnetic analysis of the motor indicates that the permanent magnet height ought to be taken in such a way that it is under the influence of electromagnetic field of current carrying coil as well as the outer core in the balanced position. This is necessary so that sufficient amount of thrust force is developed by efficient utilisation of the air gap flux density. Also, the outer core ends need to be designed to facilitate enough room for the magnet movement under the operating conditions.

  17. Contact analysis and experimental investigation of a linear ultrasonic motor.

    Lv, Qibao; Yao, Zhiyuan; Li, Xiang

    2017-11-01

    The effects of surface roughness are not considered in the traditional motor model which fails to reflect the actual contact mechanism between the stator and slider. An analytical model for calculating the tangential force of linear ultrasonic motor is proposed in this article. The presented model differs from the previous spring contact model, the asperities in contact between stator and slider are considered. The influences of preload and exciting voltage on tangential force in moving direction are analyzed. An experiment is performed to verify the feasibility of this proposed model by comparing the simulation results with the measured data. Moreover, the proposed model and spring model are compared. The results reveal that the proposed model is more accurate than spring model. The discussion is helpful for designing and modeling of linear ultrasonic motors. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Force analysis of linear induction motor for magnetic levitation system

    Kuijpers, A.A.; Nemlioglu, C.; Sahin, F.; Verdel, A.J.D.; Compter, J.C.; Lomonova, E.

    2010-01-01

    This paper presents the analyses of thrust and normal forces of linear induction motor (LIM) segments which are implemented in a rotating ring system. To obtain magnetic levitation in a cost effective and sustainable way, decoupled control of thrust and normal forces is required. This study includes

  19. Thermally driven molecular linear motors - A molecular dynamics study

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard Lawrence

    2009-01-01

    We conduct molecular dynamics simulations of a molecular linear motor consisting of coaxial carbon nanotubes with a long outer carbon nanotube confining and guiding the motion of an inner short, capsule-like nanotube. The simulations indicate that the motion of the capsule can be controlled by th...

  20. CONTRIBUTIONS TO THE FINITE ELEMENT MODELING OF LINEAR ULTRASONIC MOTORS

    Oana CHIVU

    2013-05-01

    Full Text Available The present paper is concerned with the main modeling elements as produced by means of thefinite element method of linear ultrasonic motors. Hence, first the model is designed and then a modaland harmonic analysis are carried out in view of outlining the main outcomes

  1. Resettable binary latch mechanism for use with paraffin linear motors

    Maus, Daryl; Tibbitts, Scott

    1991-01-01

    A new resettable Binary Latch Mechanism was developed utilizing a paraffin actuator as the motor. This linear actuator alternately latches between extended and retracted positions, maintaining either position with zero power consumption. The design evolution and kinematics of the latch mechanism are presented, as well as the development problems and lessons that were learned.

  2. Evaluation of linear induction motor characteristics : the Yamamura model

    1975-04-30

    The Yamamura theory of the double-sided linear induction motor (LIM) excited by a constant current source is discussed in some detail. The report begins with a derivation of thrust and airgap power using the method of vector potentials and theorem of...

  3. Position sensor for linear synchronous motors employing halbach arrays

    Post, Richard Freeman

    2014-12-23

    A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.

  4. Force measurements on a shielded coreless linear permanent magnet motor

    Pluk, K.J.W.; Jansen, J.W.; Lomonova, E.A.

    2014-01-01

    This paper compares force measurements on a shielded coreless linear permanent magnet motor with 2-D models. A 2-D semianalytical modeling method is applied, which is based on Fourier modeling and includes force calculations. The semianalytical modeling correctly predicts the behavior found in the

  5. Bidirectional electrostatic linear shuffle motor with two degrees of freedom

    Sarajlic, Edin; Berenschot, Johan W.; Fujita, H.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

    2005-01-01

    We report on an electrostatic linear inchworm micromotor with two translational degrees-of-freedom. The motor employs built-in mechanical leverage to convert normal deflection of a flexible cross-plate into a small in-plane step and four electrostatic clamps to enable bidirectional inchworm motion

  6. Magnetic shielding for coreless linear permanent magnet motors

    Pluk, K.J.W.; Jansen, J.W.; Lomonova, E.

    2013-01-01

    This paper concerns the local reduction of the magnetic flux density by means of magnetic shielding. Using a spatial frequency description, a 2-D semi-analytical periodic model is obtained for a coreless single-sided linear permanent magnet motor. The magnetic shield is included in the modeling

  7. Performance estimation of an oil-free linear compressor unit for a new compact 2K Gifford-McMahon cryocooler

    Hiratsuka, Y.; Bao, Q.; Y Xu, M.

    2017-12-01

    Since 2012, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed and reported by Sumitomo Heavy Industries, Ltd. (SHI). Also, it was reported that National Institute of Information and Communications Technology (NICT) developed a multi-channel, conduction-cooled SSPD system. However, the size and power consumption reduction becomes indispensable to apply such a system to the optical communication of AdHoc for a mobile system installed in a vehicle. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design cooling capacity targets of the first and the second stages 1 W at 60 K and 20 mW at 2.3 K respectively. In 2016, Hiratsuka et al. reported that an oil-free compressor was developed for a 2K GM cryocooler. The cooling performance of a 2K GM expander driven by an experimental unit of the linear compressor was measured. No-load temperature less than 2.1 K and the cooling capacity of 20 mW at 2.3 K were successfully achieved with an electric input power of only 1.1 kW. After that, the compressor capsule and the heat exchanger, etc. were assembled into one enclosure as a compressor unit. The total volume of the compressor unit and electrical box was significantly reduced to about 38 L, which was close to the target of 35 L. Also, the sound noise, vibration characteristics, the effect of the compressor unit inclination and the ambient temperature on the cooling performance, were evaluated. The detailed experimental results are discussed in this paper.

  8. Direct Torque Control With Feedback Linearization for Induction Motor Drives

    Lascu, Cristian; Jafarzadeh, Saeed; Fadali, Sami M.

    2017-01-01

    This paper describes a direct-torque-controlled (DTC) induction motor (IM) drive that employs feedback linearization and sliding-mode control (SMC). A new feedback linearization approach is proposed, which yields a decoupled linear IM model with two state variables: torque and stator flux magnitude....... This intuitive linear model is used to implement a DTC-type controller that preserves all DTC advantages and eliminates its main drawback, the flux and torque ripple. Robust, fast, and ripple-free control is achieved by using SMC with proportional control in the vicinity of the sliding surface. SMC assures...... in simulations. The sliding controller is compared with a linear DTC scheme with and without feedback linearization. Extensive experimental results for a sensorless IM drive validate the proposed solution....

  9. Advanced analysis technique for the evaluation of linear alternators and linear motors

    Holliday, Jeffrey C.

    1995-01-01

    A method for the mathematical analysis of linear alternator and linear motor devices and designs is described, and an example of its use is included. The technique seeks to surpass other methods of analysis by including more rigorous treatment of phenomena normally omitted or coarsely approximated such as eddy braking, non-linear material properties, and power losses generated within structures surrounding the device. The technique is broadly applicable to linear alternators and linear motors involving iron yoke structures and moving permanent magnets. The technique involves the application of Amperian current equivalents to the modeling of the moving permanent magnet components within a finite element formulation. The resulting steady state and transient mode field solutions can simultaneously account for the moving and static field sources within and around the device.

  10. Analysis of the linear induction motor in transient operation

    Gentile, G; Rotondale, N; Scarano, M

    1987-05-01

    The paper deals with the analysis of a bilateral linear induction motor in transient operation. We have considered an impressed voltage one-dimensional model which takes into account end effects. The real winding distribution of the armature has been represented as a lumped parameters system. By using the space vectors methodology, the partial differential equation of the sheet is solved bythe variable separation method. Therefore it's possible to arrange a system of ordinary differential equations where the unknown quantities are the space vectors of the air-gap flux density and sheet currents. Finally, we have analyzed the characteristic quantities for a no-load starting of small power motors.

  11. A novel linear switched reluctance motor for railway transportation systems

    Daldaban, Ferhat; Ustkoyuncu, Nurettin

    2010-01-01

    This paper presents the design and realization of a new linear switched reluctance motor (LSRM) structure, especially suitable for high-speed railway systems. The new model has a double active stator configuration and provides high force for many applications with low cost. The characteristics of the LSRM are obtained by using finite element analysis (FEA) and analytical calculations. The results of the FEA and analytical calculations are presented, and compared with experimental results. In addition, a classical double-sided LSRM (DSLSRM) is modeled with the same specifications of the new motor structure and the results are compared.

  12. ANALYSIS OVERHEATING PROBLEMS OF ELECTRIC MOTOR BY TYPE DK-409 AND MOTOR – DRIVEN COMPRESSOR BY TYPE (EK – 7B OF CONTINUOUS CURRENT LOCOMOTIVE BY TYPE (ER – 1, ER – 2 WITH USING THE THERMAL SYSTEM OF COMPENSATION

    R. V. Krasnov

    2010-11-01

    Full Text Available The article shows the method of investigation of thermal processes occurring in the electric compressor motor of rolling stock to determine the values of overheating, which will later be used to assess their impact on the state of isolation.

  13. Development of a linear induction motor based artificial muscle system.

    Gruber, A; Arguello, E; Silva, R

    2013-01-01

    We present the design of a linear induction motor based on electromagnetic interactions. The engine is capable of producing a linear movement from electricity. The design consists of stators arranged in parallel, which produce a magnetic field sufficient to displace a plunger along its axial axis. Furthermore, the winding has a shell and cap of ferromagnetic material that amplifies the magnetic field. This produces a force along the length of the motor that is similar to that of skeletal muscle. In principle, the objective is to use the engine in the development of an artificial muscle system for prosthetic applications, but it could have multiple applications, not only in the medical field, but in other industries.

  14. Generate stepper motor linear speed profile in real time

    Stoychitch, M. Y.

    2018-01-01

    In this paper we consider the problem of realization of linear speed profile of stepper motors in real time. We considered the general case when changes of speed in the phases of acceleration and deceleration are different. The new and practical algorithm of the trajectory planning is given. The algorithms of the real time speed control which are suitable for realization to the microcontroller and FPGA circuits are proposed. The practical realization one of these algorithms, using Arduino platform, is given also.

  15. Electromagnetic Energy Converters - Rotating Motors and Linear Generators

    Ekergaard, Boel

    2011-07-01

    This licentiate thesis presents a study of the electromagnetic properties of linear synchronous permanent magnet generators, utilized in wave energy converters, and a two pole permanent magnet motor for an electrical vehicle. Both machine topologies are presented, designed with a numerical simulation tool, based on a model derived from Maxwell's equations. Full scale prototypes of both the machines are under construction. A continued study about the impact on the magnetic circuit caused by the longitudinal ends of a linear generator is performed. The results present significant core losses in the translator and an increased cogging force caused by the longitudinal ends. Further, a new electric conversion circuit based on the electric resonance phenomena is presented. Experimental results indicate that a successful electric resonance between the generator and external circuit has been achieved. Finally, detailed analytical and numerical methods are utilized to investigate the losses in the two pole permanent magnet motor over a wide frequency interval. The results indicate that the efficiency of electrical motors in electrical vehicle system can be increased relative existing designs and argue for limiting of the gearbox. The system total efficiency and mechanical stability can thereby be increased. The work concerning the wave energy converter is a part of a larger project, the so called Lysekil Wave Power Project, whereas the work concerning the electric motor so far has been carried out as an individual project. However, a future goal is to integrate the research on the electric motor for electrical vehicle with closely related ongoing research regarding a flywheel based electric driveline for an All Electric Propulsion System

  16. Design and optimization of a modal- independent linear ultrasonic motor.

    Zhou, Shengli; Yao, Zhiyuan

    2014-03-01

    To simplify the design of the linear ultrasonic motor (LUSM) and improve its output performance, a method of modal decoupling for LUSMs is proposed in this paper. The specific embodiment of this method is decoupling of the traditional LUSM stator's complex vibration into two simple vibrations, with each vibration implemented by one vibrator. Because the two vibrators are designed independently, their frequencies can be tuned independently and frequency consistency is easy to achieve. Thus, the method can simplify the design of the LUSM. Based on this method, a prototype modal- independent LUSM is designed and fabricated. The motor reaches its maximum thrust force of 47 N, maximum unloaded speed of 0.43 m/s, and maximum power of 7.85 W at applied voltage of 200 Vpp. The motor's structure is then optimized by controlling the difference between the two vibrators' resonance frequencies to reach larger output speed, thrust, and power. The optimized results show that when the frequency difference is 73 Hz, the output force, speed, and power reach their maximum values. At the input voltage of 200 Vpp, the motor reaches its maximum thrust force of 64.2 N, maximum unloaded speed of 0.76 m/s, maximum power of 17.4 W, maximum thrust-weight ratio of 23.7, and maximum efficiency of 39.6%.

  17. Improvement of the thermal behavior of linear motors through insulation layer

    Eun, I. U.; Lee, C. M.; Chung, W. J.; Choi, Y. H.

    2001-01-01

    Linear motors can drive a linear motion without intermediate gears, screws or crank shafts. Linear motors can successfully replace ball lead screw in machine tools, because they have a high velocity, acceleration and good positioning accuracy. On the other hand, linear motors emit large amounts of heat and have low efficiency. In this paper, heat sources of a synchronous linear motor with high velocity and force are measured and analyzed. To improve the thermal stiffness of the linear motor, an insulation layer with low thermal conductivity is inserted between cooler and machine table. Some effects of the insulation layer are presented

  18. Rotary Compressor Noise Analysis Using Mechanisms and Electromagnetics Coupled Approach

    Chung, Jinah; Lee, Uiyoon; Lee, Jeongbae; Lee, Unseop; Han, Eunsil; Yoon, Jinhwan

    2016-01-01

    This research is conducted to investigate noise source and design low noise compressors. For improving energy efficiency, the rotary compressor with variable speed brushless DC motor is increasingly adopted for appliances. However brushless DC motor makes more compressor vibration than constant speed motor compressor at high speed operating condition. Therefore it is necessary to reduce noise and vibration for improving air conditioner quality. In this study, compressor’s noise and vibrat...

  19. Dynamic Response Analysis of Linear Pulse Motor with Closed Loop Control

    山本, 行雄; 山田, 一

    1989-01-01

    A linear pulse motor can translate digital signals into linear positions without a gear system. It is important to predict a dynamic response in order to the motor that has the good performance. In this report the maximum pulse rate and the maximum speed on the linear pulse motor are obtained by using the sampling theory.

  20. NASTRAN buckling study of a linear induction motor reaction rail

    Williams, J. G.

    1973-01-01

    NASTRAN was used to study problems associated with the installation of a linear induction motor reaction rail test track. Specific problems studied include determination of the critical axial compressive buckling stress and establishment of the lateral stiffness of the reaction rail under combined loads. NASTRAN results were compared with experimentally obtained values and satisfactory agreement was obtained. The reaction rail was found to buckle at an axial compressive stress of 11,400 pounds per square inch. The results of this investigation were used to select procedures for installation of the reaction rail.

  1. Cortical Contribution to Linear, Non-linear and Frequency Components of Motor Variability Control during Standing.

    König Ignasiak, Niklas; Habermacher, Lars; Taylor, William R; Singh, Navrag B

    2017-01-01

    Motor variability is an inherent feature of all human movements and reflects the quality of functional task performance. Depending on the requirements of the motor task, the human sensory-motor system is thought to be able to flexibly govern the appropriate level of variability. However, it remains unclear which neurophysiological structures are responsible for the control of motor variability. In this study, we tested the contribution of cortical cognitive resources on the control of motor variability (in this case postural sway) using a dual-task paradigm and furthermore observed potential changes in control strategy by evaluating Ia-afferent integration (H-reflex). Twenty healthy subjects were instructed to stand relaxed on a force plate with eyes open and closed, as well as while trying to minimize sway magnitude and performing a "subtracting-sevens" cognitive task. In total 25 linear and non-linear parameters were used to evaluate postural sway, which were combined using a Principal Components procedure. Neurophysiological response of Ia-afferent reflex loop was quantified using the Hoffman reflex. In order to assess the contribution of the H-reflex on the sway outcome in the different standing conditions multiple mixed-model ANCOVAs were performed. The results suggest that subjects were unable to further minimize their sway, despite actively focusing to do so. The dual-task had a destabilizing effect on PS, which could partly (by 4%) be counter-balanced by increasing reliance on Ia-afferent information. The effect of the dual-task was larger than the protective mechanism of increasing Ia-afferent information. We, therefore, conclude that cortical structures, as compared to peripheral reflex loops, play a dominant role in the control of motor variability.

  2. Commercializing a U.S. piezoceramic linear motor

    Diehl, Rick W.

    2000-06-01

    A small low-cost piezoceramic linear motor has been developed in the US and is being commercialized by EDO Corporation, working with a leading motion control OEM and with a prominent US corporate research laboratory. First generation motor design has emphasized high displacement at up to 200mm per second velocity with 3.5 Newtons force with high resolution, short time constant and a 15 volt power supply at a cost of less than 100 dollars. Motor dimensions of 30 by 50 by 4 mm allow broad configuration choices, al hidden within the motion control slide. The EDO approach was to build on its core competence in high reliability electroceramic material engineering and production, and to use a strategy of back-integrating, or outsourcing of recent advances outside Edo in piezoceramics, while forward- integrating into specific emerging applications known intimately by the OEM in the market. The strategy provided design focus that has led to a cost-effective advance in 'solid-state actuation and control'. This is considered a classic case of successful industrial integration of an enabling technology across organizations in order to access the needed mix of technology for development of an innovative and competitive solution.

  3. Linear magnetic spring and spring/motor combination

    Patt, Paul J. (Inventor); Stolfi, Fred R. (Inventor)

    1991-01-01

    A magnetic spring, or a spring and motor combination, providing a linear spring force characteristic in each direction from a neutral position, in which the spring action may occur for any desired coordinate of a typical orthogonal coordinate system. A set of magnets are disposed, preferably symmetrically about a coordinate axis, poled orthogonally to the desired force direction. A second set of magnets, respectively poled opposite the first set, are arranged on the sprung article. The magnets of one of the sets are spaced a greater distance apart than those of the other, such that an end magnet from each set forms a pair having preferably planar faces parallel to the direction of spring force, the faces being offset so that in a neutral position the outer edge of the closer spaced magnet set is aligned with the inner edge of the greater spaced magnet set. For use as a motor, a coil can be arranged with conductors orthogonal to both the magnet pole directions and the direction of desired spring force, located across from the magnets of one set and fixed with respect to the magnets of the other set. In a cylindrical coordinate system having axial spring force, the magnets are radially poled and motor coils are concentric with the cylinder axis.

  4. Development of an Experimental Test Section for Forcing Unsteady Flow in a Linear Compressor Cascade using Circular Rods

    Wade, Patrick

    2003-01-01

    Upstream propagating waves impinging on a cascade of compressor blades were examined in an effort to better understand the influence of downstream components on high cycle fatigue in turbine engines...

  5. The linear electric motor: Instability at 1,000 g's

    Hunter, S.

    1997-01-01

    When fluid of high density is supported against gravity by a less dense liquid, the system is unstable, and microscopic perturbations grow at the interface between the fluids. This phenomenon, called the Rayleigh-Taylor instability, also occurs when a bottle of oil-and-vinegar salad dressing is turned upside down. The instability causes spikes of the dense fluid to penetrate the light fluid, while bubbles of the lighter fluid rise into the dense fluid. The same phenomenon occurs when a light fluid is used to accelerate a dense fluid, causing the two fluids to mix at a very high rate. For example, during the implosion of an ICF capsule, this instability can cause enough mixing to contaminate, cool, and degrade the yield of the thermonuclear fuel. The LEM is an excellent tool for studying this instability, but what is it? Think of a miniature high-speed electric train (the container) hurtling down a track (the electrodes) while diagnostic equipment (optical and laser) photographs it. The LEM, consists of four linear electrodes, or rails, that carry an electrical current to a pair of sliding armatures on the container. A magnetic field is produced that works in concert with the rail-armature current to accelerate the container--just as in an electric motor, but in a linear fashion rather than in rotation. The magnetic field is augmented with elongated coils just as in a conventional electric motor. This configuration also helps hold the armatures against the electrodes to prevent arcing. The electrical energy (0.6 megajoules) is provided by 16 capacitor banks that can be triggered independently to produce different acceleration profiles (i.e., how the acceleration varies with time)

  6. Energy saving avoiding the centrifugal motor-compressors air vents discharge to the surrounding atmosphere; Ahorro de energia evitando venteo de aire a la atmosfera en motocompresores centrifugos

    Serrano, Alex [Compressor Controls Corporation, Houston, TX (United States)

    1996-12-31

    The motor-compressors are a key part of the industrial processes. The reliability and efficient operation of a compressor is critical. The surge phenomenon is a threat in the reliability of a compressor and therefore for the process. Surge, in a centrifugal compressor is defined as a dramatic flow and pressure drop, including back-flow. This is always a significant process disturbance. Continuous surge results into costly process shutdowns and mechanical damages. To prevent surge, and control the discharge pressure with simple or obsolete controls it is needed to vent air to the surrounding atmosphere. This form of control is very inefficient and costly. An advanced control with leading technology, besides providing an economical value preventing surge damages, offers substantial energy saving reducing or eliminating the venting of air to the atmosphere. [Espanol] Los motocompresores son un aparte clave de los procesos industriales. La confiable y eficiente operacion de un compresor es critica. El fenomeno de surge es una amenaza a la confiabilidad de un compresor y por lo tanto del proceso. El surge en un compresor centrifugo es definido como una dramatica caida de flujo y presion, incluyendo flujo inverso. Esto es siempre un significante disturbio del proceso. El surge continuo resulta en costosos paros de proceso y danos mecanicos. Para prevenir el surge y controlar la presion de descarga con controles simples u obsoletos, es necesario ventear aire a la atmosfera. Esta forma de control es muy ineficiente y costosa. Un control avanzado con tecnologia de punta ademas de proveer valor economico previniendo danos por surge, provee sustanciales ahorros de energia reduciendo o eliminando el venteo de aire a la atmosfera.

  7. Energy saving avoiding the centrifugal motor-compressors air vents discharge to the surrounding atmosphere; Ahorro de energia evitando venteo de aire a la atmosfera en motocompresores centrifugos

    Serrano, Alex [Compressor Controls Corporation, Houston, TX (United States)

    1997-12-31

    The motor-compressors are a key part of the industrial processes. The reliability and efficient operation of a compressor is critical. The surge phenomenon is a threat in the reliability of a compressor and therefore for the process. Surge, in a centrifugal compressor is defined as a dramatic flow and pressure drop, including back-flow. This is always a significant process disturbance. Continuous surge results into costly process shutdowns and mechanical damages. To prevent surge, and control the discharge pressure with simple or obsolete controls it is needed to vent air to the surrounding atmosphere. This form of control is very inefficient and costly. An advanced control with leading technology, besides providing an economical value preventing surge damages, offers substantial energy saving reducing or eliminating the venting of air to the atmosphere. [Espanol] Los motocompresores son un aparte clave de los procesos industriales. La confiable y eficiente operacion de un compresor es critica. El fenomeno de surge es una amenaza a la confiabilidad de un compresor y por lo tanto del proceso. El surge en un compresor centrifugo es definido como una dramatica caida de flujo y presion, incluyendo flujo inverso. Esto es siempre un significante disturbio del proceso. El surge continuo resulta en costosos paros de proceso y danos mecanicos. Para prevenir el surge y controlar la presion de descarga con controles simples u obsoletos, es necesario ventear aire a la atmosfera. Esta forma de control es muy ineficiente y costosa. Un control avanzado con tecnologia de punta ademas de proveer valor economico previniendo danos por surge, provee sustanciales ahorros de energia reduciendo o eliminando el venteo de aire a la atmosfera.

  8. Rotor dynamic behaviour of a high-speed oil-free motor compressor with a rigid coupling supported on four radial magnetic bearings

    Schmied, J.; Pradetto, J. C.

    1994-01-01

    The combination of a high-speed motor, dry gas seals, and magnetic bearings realized in this unit facilitates the elimination of oil. The motor is coupled with a quill shaft to the compressor. This yields higher natural frequencies of the rotor than with the use of a diaphragm coupling and helps to maintain a sufficient margin of the maximum speed to the frequency of the second compressor bending mode. However, the controller of each bearing then has to take the combined modes of both machines into account. The requirements for the controller to ensure stability and sufficient damping of all critical speeds are designed and compared with the implemented controller. The calculated closed loop behavior was confirmed experimentally, except the stability of some higher modes due to slight frequency deviations of the rotor model to the actual rotor. The influence of a mechanical damper as a device to provide additional damping to high models is demonstrated theoretically. After all, it was not necessary to install the damper, since all modes cold be stabilized by the controller.

  9. Low-Rank Linear Dynamical Systems for Motor Imagery EEG.

    Zhang, Wenchang; Sun, Fuchun; Tan, Chuanqi; Liu, Shaobo

    2016-01-01

    The common spatial pattern (CSP) and other spatiospectral feature extraction methods have become the most effective and successful approaches to solve the problem of motor imagery electroencephalography (MI-EEG) pattern recognition from multichannel neural activity in recent years. However, these methods need a lot of preprocessing and postprocessing such as filtering, demean, and spatiospectral feature fusion, which influence the classification accuracy easily. In this paper, we utilize linear dynamical systems (LDSs) for EEG signals feature extraction and classification. LDSs model has lots of advantages such as simultaneous spatial and temporal feature matrix generation, free of preprocessing or postprocessing, and low cost. Furthermore, a low-rank matrix decomposition approach is introduced to get rid of noise and resting state component in order to improve the robustness of the system. Then, we propose a low-rank LDSs algorithm to decompose feature subspace of LDSs on finite Grassmannian and obtain a better performance. Extensive experiments are carried out on public dataset from "BCI Competition III Dataset IVa" and "BCI Competition IV Database 2a." The results show that our proposed three methods yield higher accuracies compared with prevailing approaches such as CSP and CSSP.

  10. Optimization of a piezoelectric linear motor in terms of the contact parameters

    Ko, Hyun-Phill; Kim, Sangsig; Kang, Chong-Yun; Kim, Hyun-Jai; Yoon, Seok-Jin

    2005-01-01

    The contact kinetics of piezoelectric linear motors determines the operational characteristics like speed and torque or transmitted mechanical power and efficiency. Piezoelectric linear motors are driven by tangential stress in the interface between tip of shaking beam and slider. A good contact between the tip and slider is necessary for a reliable analysis of the motor, which is needed for the optimization of its performance. The piezoelectric linear motor was fabricated and the characteristics of the motor were investigated by external conditions such as tip shape with different curvatures and contact force between the tip and the slider. It was found in this investigation that the optimal curvature of the tip and the contact force are curvature of 1 and 10, respectively, for the high actuating speed, and curvature of 1 and 40 N, respectively, for the high actuating force. Finally, tip shape has an influence on the characteristics of linear motor

  11. Analysis and Design of Double-sided Air core Linear Servo Motor with Trapezoidal Permanent Magnets

    Zhang, Yuqiu; Yang, Zilong; Yu, Minghu

    2011-01-01

    In order to reduce the thrust ripple of linear servo system, a double-sided air core permanent magnet linear servo motor with trapezoidal shape permanent magnets (TDAPMLSM) is proposed in this paper. An analytical model of the motor for predicting the magnetic field in the air-gap at no...

  12. Design of linear pulse motor for control element drive mechanism of SMART

    Kim, J. H.; Huh, H.; Kim, J. I.; Jang, M. H.; Kang, D. H.

    1999-01-01

    49 Control Rod Drive Mechanisms(CEDMs) are densely installed on the reactor central head of SMART. The structural design should ensure the space for maintenance/repair, cable routing, and heat release from the motor. In this paper, an improved design is presented to enlarge the space between CEDMs by decreasing the diameter of linear pulse motor. The reduction of motor thrust force due to the decrease of the motor diameter is compensated by resizing the other structural components

  13. Direct torque control via feedback linearization for permanent magnet synchronous motor drives

    Lascu, Cristian; Boldea, Ion; Blaabjerg, Frede

    2012-01-01

    The paper describes a direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drive that employs feedback linearization and uses sliding-mode and linear controllers. We introduce a new feedback linearization approach that yields a decoupled linear PMSM model with two state...

  14. A Study on the Design of PM Exited Transverse Flux Linear Motor for Ropeless Elevator

    Kang, Do Hyun; Bang, Deok Je; Kim, Jong Moo; Jeong, Yeon Ho [Korea Electrotechnology Research Institute (Korea); Kim, Moon Hwan [Silla University (Korea)

    2000-03-01

    The topological investigations regarding magnetic circuit geometry and winding form of the transverse flux machine have brought up a variety of constructable arrangements with different features for several types of application[1, 2]. Here with, a novel PM-exited linear motor with inner mover, based on the transverse flux configuration leads to a considerable increase in power density for moving part. In this study we designed PM-exited transverse flux linear motor for ropeless elevator, whose output power density is higher and weight is lighter than conventional linear synchronous motors, When the designed motor in this study is applied to ropeless elevator, it is possible to increase power density more than 400% comparing with PM exited linear synchronous motor. The result of this study can be utilized for ropeless elevator or gearless direct linear moving system with high output[3]. (author). 8 refs., 9 figs., 4 tabs.

  15. A square-plate ultrasonic linear motor operating in two orthogonal first bending modes.

    Chen, Zhijiang; Li, Xiaotian; Chen, Jianguo; Dong, Shuxiang

    2013-01-01

    A novel square-plate piezoelectric ultrasonic linear motor operated in two orthogonal first bending vibration modes (B₁) is proposed. The piezoelectric vibrator of the linear motor is simply made of a single PZT ceramic plate (sizes: 15 x 15 x 2 mm) and poled in its thickness direction. The top surface electrode of the square ceramic plate was divided into four active areas along its two diagonal lines for exciting two orthogonal B₁ modes. The achieved driving force and speed from the linear motor are 1.8 N and 230 mm/s, respectively, under one pair orthogonal voltage drive of 150 V(p-p) at the resonance frequency of 92 kHz. The proposed linear motor has advantages over conventional ultrasonic linear motors, such as relatively larger driving force, very simple working mode and structure, and low fabrication cost.

  16. Influence analysis of structural parameters on electromagnetic properties of HTS linear induction motor

    Zhao, J.; Zheng, T.Q.; Zhang, W.; Fang, J.; Liu, Y.M.

    2011-01-01

    A new type high temperature superconductor linear induction motor is designed and analyzed as a prototype to ensure applicability aimed at industrial motors. Made of Bi-2223/Ag, primary windings are distributed with the double-layer concentrated structure. The motor is analyzed by 2D electromagnetic Finite Element Method to get magnetic field distribution, thrust force, vertical force and so on. The critical current of motor and the electromagnetic force are mostly decided by the leakage flux density of primary slot and by the main magnetic flux and eddy current respectively. The structural parameters of motor have a great influence on the distribution of magnetic field. Under constant currents, the properties of motor are analyzed with different slot widths, slot heights and winding turns. The properties of motor, such as the maximum slot leakage flux density, motor thrust and motor vertical force, are analyzed with different structural parameters.

  17. Design and performance testing of an ultrasonic linear motor with dual piezoelectric actuators.

    Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Laoratanakul, Pitak; Muensit, Nantakan

    2012-05-01

    In this work, design and performance testing of an ultrasonic linear motor with dual piezoelectric actuator patches are studied. The motor system consists of a linear stator, a pre-load weight, and two piezoelectric actuator patches. The piezoelectric actuators are bonded with the linear elastic stator at specific locations. The stator generates propagating waves when the piezoelectric actuators are subjected to harmonic excitations. Vibration characteristics of the linear stator are analyzed and compared with finite element and experimental results. The analytical, finite element, and experimental results show agreement. In the experiments, performance of the ultrasonic linear motor is tested. Relationships between velocity and pre-load weight, velocity and applied voltage, driving force and applied voltage, and velocity and driving force are reported. The design of the dual piezoelectric actuators yields a simpler structure with a smaller number of actuators and lower stator stiffness compared with a conventional design of an ultrasonic linear motor with fully laminated piezoelectric actuators.

  18. Oil-Free Compressor

    Fitzjerrell, D. G.; Belver, T. L.; Moore, H. E.

    1986-01-01

    Compressor pistons moved by eccentric shaft need no lubricants. Compressor has shaft, middle section is eccentric in relation to end sections. Driven by brushless dc motor, shaft turns inner races of set of four cam bearings. Outer cam-bearing races in turn actuate four pistons spaced equally apart, around and along shaft. Each outer bearing race held in position by pressure exerted on it by piston. Because no frictional motion between piston and outer bearing race, lubricant between them unnecessary. Cam bearings themselves contain potted internal lubricant. Originally proposed for use in space, new compressor for refrigerators or freezers does not depend on pool of oil for lubricating its pistons. Operated in any orientation.

  19. New technology of subsea and offshore compressor

    Almasi, Amin

    2012-09-15

    Subsea compressor is a hot topic. Subsea compressor offers tremendous potentials, but also some obstacles. Active magnetic bearings installed inside the process gas allow the elimination of lubrication and seal systems. High-speed permanent- magnet motor directly drives centrifugal compressor to meet optimum speed, eliminating gear box. This design offers inherent machinery health monitoring features and very compact and reliable train. New technology of hermitically sealed direct drive centrifugal compressor for offshore and subsea applications are discussed and case studies for horizontal and vertical compressor train arrangements are presented. (orig.)

  20. Traveling-wave piezoelectric linear motor part II: experiment and performance evaluation.

    Ting, Yung; Li, Chun-Chung; Chen, Liang-Chiang; Yang, Chieh-Min

    2007-04-01

    This article continues the discussion of a traveling-wave piezoelectric linear motor. Part I of this article dealt with the design and analysis of the stator of a traveling-wave piezoelectric linear motor. In this part, the discussion focuses on the structure and modeling of the contact layer and the carriage. In addition, the performance analysis and evaluation of the linear motor also are dealt with in this study. The traveling wave is created by stator, which is constructed by a series of bimorph actuators arranged in a line and connected to form a meander-line structure. Analytical and experimental results of the performance are presented and shown to be almost in agreement. Power losses due to friction and transmission are studied and found to be significant. Compared with other types of linear motors, the motor in this study is capable of supporting heavier loads and provides a larger thrust force.

  1. Linear summation of outputs in a balanced network model of motor cortex.

    Capaday, Charles; van Vreeswijk, Carl

    2015-01-01

    Given the non-linearities of the neural circuitry's elements, we would expect cortical circuits to respond non-linearly when activated. Surprisingly, when two points in the motor cortex are activated simultaneously, the EMG responses are the linear sum of the responses evoked by each of the points activated separately. Additionally, the corticospinal transfer function is close to linear, implying that the synaptic interactions in motor cortex must be effectively linear. To account for this, here we develop a model of motor cortex composed of multiple interconnected points, each comprised of reciprocally connected excitatory and inhibitory neurons. We show how non-linearities in neuronal transfer functions are eschewed by strong synaptic interactions within each point. Consequently, the simultaneous activation of multiple points results in a linear summation of their respective outputs. We also consider the effects of reduction of inhibition at a cortical point when one or more surrounding points are active. The network response in this condition is linear over an approximately two- to three-fold decrease of inhibitory feedback strength. This result supports the idea that focal disinhibition allows linear coupling of motor cortical points to generate movement related muscle activation patterns; albeit with a limitation on gain control. The model also explains why neural activity does not spread as far out as the axonal connectivity allows, whilst also explaining why distant cortical points can be, nonetheless, functionally coupled by focal disinhibition. Finally, we discuss the advantages that linear interactions at the cortical level afford to motor command synthesis.

  2. A helium regenerative compressor

    Swift, W.L.; Nutt, W.E.; Sixsmith, H.

    1994-01-01

    This paper discusses the design and performance of a regenerative compressor that was developed primarily for use in cryogenic helium systems. The objectives for the development were to achieve acceptable efficiency in the machine using conventional motor and bearing technology while reducing the complexity of the system required to control contamination from the lubricants. A single stage compressor was built and tested. The compressor incorporates aerodynamically shaped blades on a 218 mm (8.6 inches) diameter impeller to achieve high efficiency. A gas-buffered non-contact shaft seal is used to oppose the diffusion of lubricant from the motor bearings into the cryogenic circuit. Since it is a rotating machine, the flow is continuous and steady, and the machine is very quiet. During performance testing with helium, the single stage machine has demonstrated a pressure ratio of 1.5 at a flow rate of 12 g/s with measured isothermal efficiencies in excess of 30%. This performance compares favorably with efficiencies generally achieved in oil flooded screw compressors

  3. Mathematical models of flat linear induction motors used in mining drives

    Tall, M

    1984-01-01

    Design parameters are calculated for electric flat linear induction motors, widely employed in the coal and ore mining industries in Poland. A mathematical model of this motor with a single-layer ferromagnetic secondary part is presented. A three-dimensional electromagnetic field analysis is carried out, taking relative magnetic permeability variation, discrete winding distribution, influence of armature grooving and pulsating field influence into account. A computer calculation algorithm is proposed for determining motor characteristics. 17 refs.

  4. Effect of Frequency and Spatial-Harmonics on Rotary and Linear Induction Motor Characteristics

    1972-03-01

    A computer analysis is made of the effect of current and MMF airgap harmonics on the output characteristics of rotary and linear induction motors. The current harmonics accompanying thyristor-control operation are evaluated by Fourier analyzing the p...

  5. A standing wave linear ultrasonic motor operating in in-plane expanding and bending modes.

    Chen, Zhijiang; Li, Xiaotian; Ci, Penghong; Liu, Guoxi; Dong, Shuxiang

    2015-03-01

    A novel standing wave linear ultrasonic motor operating in in-plane expanding and bending modes was proposed in this study. The stator (or actuator) of the linear motor was made of a simple single Lead Zirconate Titanate (PZT) ceramic square plate (15 × 15 × 2 mm(3)) with a circular hole (D = 6.7 mm) in the center. The geometric parameters of the stator were computed with the finite element analysis to produce in-plane bi-mode standing wave vibration. The calculated results predicted that a driving tip attached at midpoint of one edge of the stator can produce two orthogonal, approximate straight-line trajectories, which can be used to move a slider in linear motion via frictional forces in forward or reverse direction. The investigations showed that the proposed linear motor can produce a six times higher power density than that of a previously reported square plate motor.

  6. Coreless Linear Induction Motor (LIM) for Space-borne Electro-magnetic Mass Driver Applications

    National Aeronautics and Space Administration — Large scale linear induction motors use ferromagnetic cores, but at high speed these cores choke the system’s ability to transform electrical energy into mechanical...

  7. Linear estimation discriminates midline sources and motor cortex contribution to the readiness potential

    Knosche, Thomas; Knosche, T.R.; Praamstra, Peter; Peters, M.J.; Stegeman, Dick; Stegeman, D.

    1996-01-01

    Spatiotemporal dipole modelling of the generators of the readiness potential (RP) prior to voluntary movements has yielded diverging results concerning the contributions of supplementary motor area (SMA) and primary motor cortex. We applied an alternative approach (i.e. linear estimation theory) to

  8. MAGNETIC INDUCTION DISTRIBUTION IN A LINEAR SYNCHRONUS MOTOR WITH MAGNETIC SUSPENSION

    D.I. Parkhomenko

    2013-02-01

    Full Text Available Results of computer simulation and experimental investigations of magnetic induction distribution in a coaxial linear synchronous motor with magnetic suspension are presented. The magnetic induction distribution has been studied both in the motor air gap and on the runner surface.

  9. Study on a high thrust force bi-double-sided permanent magnet linear synchronous motor

    Liang Tong

    2016-03-01

    Full Text Available A high thrust force bi-double-sided permanent magnet linear synchronous motor used in gantry-type five-axis machining center is designed and its performance was tested in this article. This motor is the subproject of Chinese National Science and Technology Major Project named as “development of domestic large thrust linear motor used in high-speed gantry-type five-axis machining center project” jointly participated by enterprises and universities. According to the requirement of the application environment and motor performance parameters, the linear motor’s basic dimensions, form of windings, and magnet arrangement are preliminarily specified through theoretical analysis and calculation. To verify the correctness of the result of the calculation, the finite element model of the motor is established. The static and dynamic characteristics of the motor are studied and analyzed through the finite element method, and the initial scheme is revised. The prototype of the motor is manufactured based on the final revised structure parameters, and the performance of the motor is fully tested using the evaluation platform for direct-drive motor component. Experimental test results meet the design requirements and show the effectiveness of design method and process.

  10. Fluid powered linear piston motor with harmonic coupling

    Raymond, David W.

    2016-09-20

    A motor is disclosed that includes a module assembly including a piston that is axially cycled. The piston axial motion is coupled to torque couplers that convert the axial motion into rotary motion. The torque couplers are coupled to a rotor to rotate the rotor.

  11. A T-shape linear piezoelectric motor with single foot.

    Liu, Yingxiang; Chen, Weishan; Yang, Xiaohui; Liu, Junkao

    2015-02-01

    A new T-shape piezoelectric motor using the hybrid of two orthogonal longitudinal vibrations is proposed in this work. Six pieces of PZT ceramic plates are bonded on the upside and downside surfaces of a T-shape duralumin alloy base respectively to form the proposed motor. Elliptical movement can be generated on the driving tip by applying sine and cosine voltages to the PZT elements. The horizontal displacement of the driving tip will push the runner while the vertical displacement can overcome the preload. Finite element method is used to accomplish the design and analysis process. The resonance frequencies of the two vibration modes are tuned to be close by modal analysis, while the motion trajectory of the driving tip is observed by transient analysis. After the fabrication of a prototype, the vibration characteristics and mechanical output ability are measured. The no-load speed and the maximum output thrust force of the proposed motor are tested to be 718 mm/s and 3.5 N under an exciting frequency of 53.1 kHz. The proposed T-shape piezoelectric motor exhibits merits of simple structure, easy to realize miniaturization, easy to be fabricated, and high power-to-weight ratio. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Development of a sub-nanometer positioning device: combining a new linear motor with linear motion ball guide ways

    Otsuka, J; Tanaka, T; Masuda, I

    2010-01-01

    A new type of linear motor described in this note has some advantages compared with conventional motors. The attractive magnetic force between the stator (permanent magnets) and mover (armature) is diminished almost to zero. The efficiency is better because the magnetic flux leakage is very small, the size of motor is smaller and detent (force ripple) is smaller than for conventional motors. Therefore, we think that this motor is greatly suitable for ultra-precision positioning as an actuator. An ultra-precision positioning device using this motor and linear motion ball guide ways is newly developed by making the device very rigid and using a suitable control method. Moreover, the positioning performance is evaluated by a positioning resolution, and deviation and dispersion errors. As a result of repeated step response tests, the positioning resolution is 0.3 nm, with the deviation error and dispersion error (3σ) being sub-nanometer. Consequently, the positioning device achieves sub-nanometer positioning. (technical design note)

  13. Principle and analysis of a linear motor driving system for HTS levitation applications

    Jin, Jian X.; Guo, You G.; Zhu, Jian G.

    2007-01-01

    High temperature superconductor (HTS) high levitation force density with passive and self-stabilizing features allows a number of special applications to be developed. Linear motor driving systems are commonly required for those applications such as levitated transport systems. In this paper a prototype linear motor driving system with HTS is analyzed with calculation details including its magnetic fields and driving forces presented in the paper

  14. Comprehensive model of a hermetic reciprocating compressor

    Yang, B.; Ziviani, D.; Groll, E. A.

    2017-08-01

    A comprehensive simulation model is presented to predict the performance of a hermetic reciprocating compressor and to reveal the underlying mechanisms when the compressor is running. The presented model is composed of sub-models simulating the in-cylinder compression process, piston ring/journal bearing frictional power loss, single phase induction motor and the overall compressor energy balance among different compressor components. The valve model, leakage through piston ring model and in-cylinder heat transfer model are also incorporated into the in-cylinder compression process model. A numerical algorithm solving the model is introduced. The predicted results of the compressor mass flow rate and input power consumption are compared to the published compressor map values. Future work will focus on detailed experimental validation of the model and parametric studies investigating the effects of structural parameters, including the stroke-to-bore ratio, on the compressor performance.

  15. Direct torque control with feedback linearization for induction motor drives

    Lascu, Cristian; Jafarzadeh, Saeed; Fadali, Sami M.

    2015-01-01

    This paper describes a Direct Torque Controlled (DTC) Induction Machine (IM) drive that employs feedback linearization and sliding-mode control. A feedback linearization approach is investigated, which yields a decoupled linear IM model with two state variables: torque and stator flux magnitude....... This intuitive linear model is used to implement a DTC type controller that preserves all DTC advantages and eliminates its main drawback, the flux and torque ripple. Robust, fast, and ripple-free control is achieved by using Variable Structure Control (VSC) with proportional control in the vicinity...... robust stability analysis are presented. The sliding controller is compared with a linear DTC scheme, and experimental results for a sensorless IM drive validate the proposed solution....

  16. A double B1-mode 4-layer laminated piezoelectric linear motor.

    Li, Xiaotian; Chen, Zhijiang; Dong, Shuxiang

    2012-12-01

    We report a miniature piezoelectric ultrasonic linear motor that is made of four Pb(Zr,Ti)O(3) (PZT) piezoelectric ceramic layers for low-voltage work. The 4-layer piezoelectric laminate works in two orthogonal first-bending modes for producing elliptical oscillations, which are then used to drive a contacting slider into continuous linear motion. Experimental results show that the miniature linear motor (size: 4 × 4 × 12 mm, weight: 1.7 g) can generate a large driving force of 0.48 N and a linear motion speed of up to 160 mm/s, using a 40 V(pp)/mm voltage drive at its resonance frequency of 64.5 kHz. The maximum efficiency of the linear motor is 30%.

  17. Evaluation of synthetic linear motor-molecule actuation energetics

    Brough, Branden; Northrop, Brian H.; Schmidt, Jacob J.; Tseng, Hsian-Rong; Houk, Kendall N.; Stoddart, J. Fraser; Ho, Chih-Ming

    2006-01-01

    By applying atomic force microscope (AFM)-based force spectroscopy together with computational modeling in the form of molecular force-field simulations, we have determined quantitatively the actuation energetics of a synthetic motor-molecule. This multidisciplinary approach was performed on specifically designed, bistable, redox-controllable [2]rotaxanes to probe the steric and electrostatic interactions that dictate their mechanical switching at the single-molecule level. The fusion of expe...

  18. Stepping motor adaptor actuator for a commercial uhv linear motion feedthrough

    Iarocci, M.; Oversluizen, T.

    1989-01-01

    An adaptor coupling has been developed that will allow the attachment of a standard stepping motor to a precision commercial (Varian) uhv linear motion feedthrough. The assembly, consisting of the motor, motor adaptor, limit switches, etc. is clamped to the feedthrough body which can be done under vacuum conditions if necessary. With a 500 step/rev. stepping motor the resolution is 1.27 μm per step. We presently use this assembly in a remote location for the precise positioning of a beam sensing monitor. 2 refs., 3 figs

  19. Shuffle motor: a high force, high precision linear electrostatic stepper motor

    Tas, Niels Roelof; Wissink, Jeroen; Sander, A.F.M.; Sander, Louis; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt

    1997-01-01

    The shuffle motor is a electrostatic stepper motor that employs a mechanical transformation to obtain high forces and small steps. A model has been made to calculate the driving voltage, step size and maximum load to pull as well as the optimal geometry. Tests results are an effective step size of

  20. Design optimization of a linear permanent magnet synchronous motor for extra low force pulsations

    Isfahani, Aarsh Hassanpour; Vaez-Zadeh, Sadegh

    2007-01-01

    Air cored linear permanent magnet synchronous motors have essentially low force pulsations due to the lack of the primary iron core and teeth. However, a motor design with much lower force pulsations is required for many precise positioning systems, as in fabrication of microelectronic chips. This paper presents the design optimization of an air cored linear permanent magnet synchronous motor with extra low force pulsations for such applications. In order to achieve the goal, an analytical layer model of the machine is developed. A very effective objective function regarding force pulsations is then proposed; while the selected motor dimensions are regarded as the design variables. A genetic algorithm is used to find the optimal motor dimensions. This results in a substantial ninety percent reduction in the force pulsations. The design optimization is verified by a finite element method

  1. Drive of a rail locomotive using linear motors. Antrieb eines schienengebundenen Triebfahrzeuges mit Hilfe von Linearmotoren

    Kagischke, W; Steffen, U

    1977-12-08

    The purpose of the invention is to avoid the disadvantages of asynchronous linear motors, for example for need for reactive current for excitation, where driving on a normal section and driving on a branch line should be possible without losing the saving in weight on the inductor. According to the invention, the common inductor on a synchronous linear motor consists of 2 parallel packets of laminations surrounded by DC excitation windings and the secondary systems consists of unwound and spaced magnetic sections covering the two packets of laminations on the normal section. In the direction of thrust, their length extends nearly over the pole pitch of the multi-phase AC winding. According to the invetnion, this drive therefore consists of a synchronous linear motor combined into a double motor, with an external, rail shaped fixed secondary system, which has a multi-phase AC winding opposite it.

  2. 49 CFR 178.337-15 - Pumps and compressors.

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pumps and compressors. 178.337-15 Section 178.337... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.337-15 Pumps and compressors. (a) Liquid pumps or gas compressors, if used, must be of suitable design, adequately protected...

  3. 49 CFR 178.338-17 - Pumps and compressors.

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pumps and compressors. 178.338-17 Section 178.338... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.338-17 Pumps and compressors. (a) Liquid pumps and gas compressors, if used, must be of suitable design, adequately protected...

  4. Computation of magnetic field in DC brushless linear motors built with NdFeB magnets

    Basak, A.; Shirkoohi, G.H.

    1990-01-01

    A software package based on finite element technique has been used to compute three-dimensional magnetic fields and static forces developed in brushless d.c. linear motors. As the field flux-source two different types of permanent magnets, one of them being the high energy neodymium- iron-boron type, has been used in computer models. Motors with the same specifications as the computer models were built and experimental results obtained from them are compared with the computed results

  5. Dynamic diagnostics of moving ferromagnetic material with the linear induction motor

    Szewczyk Krzysztof; Walasek Tomasz

    2017-01-01

    The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were perfor...

  6. Efficiency Improvement of a High Dynamic BLDC Linear Motor by Multiphase Control

    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 ...

  7. Linear switched reluctance motor control with PIC18F452 microcontroller

    DURSUN, Mahir; KOÇ, Fatmagül

    2014-01-01

    This paper presents the simulation, control, and experimental results of the velocity of a double-sided, 6/4-poled, 3-phased, 8 A, 24 V, 250 W, and 250 N pull force linear switched reluctance motor (LSRM). In the simulation and experimental study, the reference velocity is constant depending on the position and time. The velocity versus the position of the translator was controlled with fuzzy logic control (FLC) and proportional-integral (PI) control techniques. The motor was control...

  8. A novel tubular linear motor equipped with radially anisotropic NdFeB ring magnets

    Hor, P.J.

    1998-01-01

    The paper describes the design synthesis and optimisation of a novel tubular linear motor employing radially magnetised anisotropic ring magnets. Design issues, related to optimising the dimensions for maximum acceleration capability, minimum cogging force and low harmonic distortion in the emf waveform, are discussed. The influence of inhomogeneities in the magnets on the performance of a prototype motor is discussed, and its dynamic performance is validated experimentally against a typical target specification for automated high-speed manufacturing applications. (orig.)

  9. The dynamic response of a linear brushless D.C. motor

    Moghani, J.S.; Eastham, J.F. [Univ. of Bath (United Kingdom). School of Electrical and Electronic Engineering

    1995-12-31

    The paper describes the use of the Matlab Analogue Simulation Toolbox SIMULINK for the closed loop dynamic modeling of a linear brushless dc motor which is supplied from a delta-modulated inverter. The work is validated by experimental results taken from a large test rig. Linear version of all rotating machines are possible; a rotating machine can be notionally cut along a radial plane and unrolled to yield a linear version. The most popular form of linear machine, as judged by the quantities that have been produced is the linear induction motor. This has the advantage of first an inexpensive secondary that is often a simple iron backed conducting plate, and secondly the possibility of simple voltage control. The linear brushless synchronous motor is potentially more expensive to produce than its induction counterpart because of the permanent magnets which provide the excitation mmf and the necessity of an inverter supply. However the machine has a power factor efficiency product which can be double that of an induction motor together with about twice the tractive force per pole area.

  10. A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet.

    Liu, Yingxiang; Liu, Junkao; Chen, Weishan; Shi, Shengjun

    2012-05-01

    A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms).

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

    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.

  12. Numerical studies on the force characteristic of superconducting linear synchronous motor with HTS bulk magnet

    Tang, Junjie; Li, Jing; Li, Xiang; Han, Le

    2018-03-01

    High temperature superconductor (HTS) bulks have significant potential use in linear motor application act as quasi-permanent magnet to replace traditional magnets. Force characteristic between HTS bulk magnet and traveling magnetic field was investigated with numerical simulation and experimental measurement in this paper. Influences of bulk height and number on the force characteristic were studied by the finite element model considering the nonlinear E-J relationship. Study was also made on addition of a back iron plate to the bulk magnet. Besides, force characteristic of bulk was compared with the permanent magnet results. The small initial decrease of the thrust could be explained by inside superconducting current redistribution. It was found that efficiency of linear motor did not increase by adding more bulk magnets. The bulk magnet will be remagnetized instead of erasing trapped field with the increase of the traveling magnetic field strength. The conclusions are helpful in prediction and design the linear motor with HTS bulk magnet.

  13. Algorithm for Controlling a Centrifugal Compressor

    Benedict, Scott M.

    2004-01-01

    An algorithm has been developed for controlling a centrifugal compressor that serves as the prime mover in a heatpump system. Experimental studies have shown that the operating conditions for maximum compressor efficiency are close to the boundary beyond which surge occurs. Compressor surge is a destructive condition in which there are instantaneous reversals of flow associated with a high outlet-to-inlet pressure differential. For a given cooling load, the algorithm sets the compressor speed at the lowest possible value while adjusting the inlet guide vane angle and diffuser vane angle to maximize efficiency, subject to an overriding requirement to prevent surge. The onset of surge is detected via the onset of oscillations of the electric current supplied to the compressor motor, associated with surge-induced oscillations of the torque exerted by and on the compressor rotor. The algorithm can be implemented in any of several computer languages.

  14. Force Profiles of a Linear Switched Reluctance Motor Having Special Pole Face Shapes

    CHADRESEKAR, V.

    2010-11-01

    Full Text Available In this paper, the results of a finite element analysis are carried out on an new stator geometry of a three phase longitudinal flux Linear Switched Reluctance Motor (LSRM. In the new geometry, pole shoes are affixed to the stator poles. Static and dynamic characteristics for the proposed structure have been highlighted. Motor performance for variable load conditions is discussed. Frequency spectrum analyses of force profile using the fast Fourier transform (FFT are described to predict the vibration frequencies. The 2-Dimensional (2-D finite element analysis (FEA and the experimental results of this paper prove that LSRMs are one of the strong candidates for linear propulsion drives.

  15. Apparatus and method to pulverize rock using a superconducting electromagnetic linear motor

    Ignatiev, Alex (Inventor)

    2009-01-01

    A rock pulverizer device based on a superconducting linear motor. The superconducting electromagnetic rock pulverizer accelerates a projectile via a superconducting linear motor and directs the projectile at high speed toward a rock structure that is to be pulverized by collision of the speeding projectile with the rock structure. The rock pulverizer is comprised of a trapped field superconducting secondary magnet mounted on a movable car following a track, a wire wound series of primary magnets mounted on the track, and the complete magnet/track system mounted on a vehicle used for movement of the pulverizer through a mine as well as for momentum transfer during launch of the rock breaking projectile.

  16. Investigation and Calculation of Magnetic Field in Tubular Linear Reluctance Motor Using FEM

    MOSALLANEJAD, A.

    2010-11-01

    Full Text Available In this paper the magnetic flux density of tubular linear reluctance motor (TLRM in open type magnetic circuit is studied. Also, all magnetic flux density calculation methods in winding of tubular linear reluctance motor are described. The effect of structure parameters on magnetic flux density is also discussed. Electromagnetic finite-element analysis is used for simulation of magnetic field, and simulation results of the magnetic field analysis with DC voltage excitation are compared with results obtained from calculation methods. The comparison yields a good agreement.

  17. International program on linear electric motors. CIGGT report No. 92-1

    Dawson, G.E.; Eastham, A.R.; Parker, J.H.

    1992-12-31

    The International Program for Linear Electric Motors (LEM) was begun in April 1989 to communicate and coordinate activities with centers of expertise in Germany, Canada, and Japan; to provide for the assessment and support of the planning of technological developments and for dissemination of information to researchers, service operators, and policy makers; and to ensure that full advantage can be taken if opportunities for technology transfer occur. This report documents the work done under the program, including standardizing linear induction motor (LIM) design characteristics; test procedures and measurement methods; rating; database for design data; criteria for evaluation of designs; computer programs for modelling performance; and a design study for an agreed application.

  18. Centrifugal Compressor Aeroelastic Analysis Code

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2002-01-01

    Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

  19. Modeling and analysis of mover gaps in tubular moving-magnet linear oscillating motors

    Xuesong LUO

    2018-05-01

    Full Text Available A tubular moving-magnet linear oscillating motor (TMMLOM has merits of high efficiency and excellent dynamic capability. To enhance the thrust performance, quasi-Halbach permanent magnet (PM arrays are arranged on its mover in the application of a linear electro-hydrostatic actuator in more electric aircraft. The arrays are assembled by several individual segments, which lead to gaps between them inevitably. To investigate the effects of the gaps on the radial magnetic flux density and the machine thrust in this paper, an analytical model is built considering both axial and radial gaps. The model is validated by finite element simulations and experimental results. Distributions of the magnetic flux are described in condition of different sizes of radial and axial gaps. Besides, the output force is also discussed in normal and end windings. Finally, the model has demonstrated that both kinds of gaps have a negative effect on the thrust, and the linear motor is more sensitive to radial ones. Keywords: Air-gap flux density, Linear motor, Mover gaps, Quasi-Halbach array, Thrust output, Tubular moving-magnet linear oscillating motor (TMMLOM

  20. Force prediction in permanent magnet flat linear motors (abstract)

    Eastham, J.F.; Akmese, R.

    1991-01-01

    The advent of neodymium iron boron rare-earth permanent magnet material has afforded the opportunity to construct linear machines of high force to weight ratio. The paper describes the design and construction of an axial flux machine and rotating drum test rig. The machine occupies an arc of 45 degree on a drum 1.22 m in diameter. The excitation is provided by blocks of NdFeB material which are skewed in order to minimize the force variations due to slotting. The stator carries a three-phase short-chorded double-layer winding of four poles. The machine is supplied by a PWM inverter the fundamental component of which is phase locked to the rotor position so that a ''dc brushless'' drive system is produced. Electromagnetic forces including ripple forces are measured at supply frequencies up to 100 Hz. They are compared with finite-element analysis which calculates the force variation over the time period. The paper then considers some of the causes of ripple torque. In particular, the force production due solely to the permanent magnet excitation is considered. This has two important components each acting along the line of motion of the machine, one is due to slotting and the other is due to the finite length of the primary. In the practical machine the excitation poles are skewed to minimize the slotting force and the effectiveness of this is confirmed by both results from the experiments and the finite-element analysis. The end effect force is shown to have a space period of twice that of the excitation. The amplitude of this force and its period are again confirmed by practical results

  1. Generating linear regression model to predict motor functions by use of laser range finder during TUG.

    Adachi, Daiki; Nishiguchi, Shu; Fukutani, Naoto; Hotta, Takayuki; Tashiro, Yuto; Morino, Saori; Shirooka, Hidehiko; Nozaki, Yuma; Hirata, Hinako; Yamaguchi, Moe; Yorozu, Ayanori; Takahashi, Masaki; Aoyama, Tomoki

    2017-05-01

    The purpose of this study was to investigate which spatial and temporal parameters of the Timed Up and Go (TUG) test are associated with motor function in elderly individuals. This study included 99 community-dwelling women aged 72.9 ± 6.3 years. Step length, step width, single support time, variability of the aforementioned parameters, gait velocity, cadence, reaction time from starting signal to first step, and minimum distance between the foot and a marker placed to 3 in front of the chair were measured using our analysis system. The 10-m walk test, five times sit-to-stand (FTSTS) test, and one-leg standing (OLS) test were used to assess motor function. Stepwise multivariate linear regression analysis was used to determine which TUG test parameters were associated with each motor function test. Finally, we calculated a predictive model for each motor function test using each regression coefficient. In stepwise linear regression analysis, step length and cadence were significantly associated with the 10-m walk test, FTSTS and OLS test. Reaction time was associated with the FTSTS test, and step width was associated with the OLS test. Each predictive model showed a strong correlation with the 10-m walk test and OLS test (P motor function test. Moreover, the TUG test time regarded as the lower extremity function and mobility has strong predictive ability in each motor function test. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  2. Linear Motor Motion Control Experiment System Design Based on LabVIEW

    Cuixian He

    2018-01-01

    Full Text Available In order to meet the needs of experimental training of electrical information industry, a linear motor motion experiment system based on LabVIEW was developed. This system is based on the STM32F103ZET6 system processor controller, a state signal when the motor moves through the grating encoder feedback controller to form a closed loop, through the RS232 serial port communication with the host computer, the host computer is designed in the LabVIEW interactive environment monitoring software. Combined with the modular design concept proposed overall program, given the detailed hardware circuit, targeted for the software function design, to achieve man-machine interface. The system control of high accuracy, good stability, meet the training requirements for laboratory equipment, but also as a reference embodiment of the linear motor monitoring system.

  3. A speed estimation unit for induction motors based on adaptive linear combiner

    Marei, Mostafa I.; Shaaban, Mostafa F.; El-Sattar, Ahmed A.

    2009-01-01

    This paper presents a new induction motor speed estimation technique, which can estimate the rotor resistance as well, from the measured voltage and current signals. Moreover, the paper utilizes a novel adaptive linear combiner (ADALINE) structure for speed and rotor resistance estimations. This structure can deal with the multi-output systems and it is called MO-ADALINE. The model of the induction motor is arranged in a linear form, in the stationary reference frame, to cope with the proposed speed estimator. There are many advantages of the proposed unit such as wide speed range capability, immunity against harmonics of measured waveforms, and precise estimation of the speed and the rotor resistance at different dynamic changes. Different types of induction motor drive systems are used to evaluate the dynamic performance and to examine the accuracy of the proposed unit for speed and rotor resistance estimation.

  4. Thrust Reduction of Magnetic Levitation Vehicle Driven by Long Stator Linear Synchronous Motor

    Wan-Tsun Tseng

    2013-01-01

    Full Text Available The propulsion technology of long stator linear synchronous motors is used to drive high-speed maglev trains. The linear synchronous motor stator is divided into sections placed on guideway. The electric power supplies to stator sections in which the train just passes in change-step mode for long-distance operation. However, a thrust drop will be caused by change-step machinery for driving magnetic vehicle. According to the train speed and vehicle data, the change-step mode has three types of operation, namely premature commutation, simultaneous commutation, and late commutation. Each type of operation has a different thrust drop which can be affected by several parameters such as jerk, running speed, motor section length, and vehicle data. This paper focuses on determining the thrust drop of the change-step mode. The study results of this paper can be used to improve the operation system of high-speed maglev trains.

  5. Application of static var compensator on large synchronous motors based on linear optimization control design

    Soltani, J.; Fath Abadi, A.M.

    2003-01-01

    This paper describes the application of static var compensators, on an electrical distribution network containing two large synchronous motors, one of which is excited via a three-phase thyristor bridge rectifier. The second machine is excited via a diode bridge rectifier. Based on linear optimization control, the measurable feedback signals are applied to the control system loops of static var compensators and the excitation control loop of the first synchronous motor. The phase equations method was used to develop a computer program to model the distribution network. Computer results were obtained to demonstrate the system performance for some abnormal modes of operation. These results show that employing static var compensators based on the linear optimization control design for electrical distribution networks containing large synchronous motors is beneficial and may be considered a first stage of the system design

  6. Thermal analysis of linear pulse motor for SMART control element drive mechanism

    Hur, H.; Kim, J. H.; Kim, J. I.; Jang, K. C.; Kang, D. H.

    1999-01-01

    It is important that the temperature of the motor windings be maintained within the allowable limit of the insulation, since the linear pulse motor of CEDM is always supplied with current during the reactor operation. In this study three motor windings were fabricated with three different diameters of coil wires, and the temperatures inside the windings were measured with different current values. As the insulation of the windings is composed of teflon, glass fiber, and air, it is not an easy task to determine experimentally the thermal properties of the complex insulation. In this study, the thermal properties of the insulation were obtained by comparing the results of finite element thermal analyses and those of experiment. The thermal properties obtained here will be used as input for the optimization analysis of the motor

  7. Speed Sensorless mixed sensitivity linear parameter variant H_inf control of the induction motor

    Toth, R.; Fodor, D.

    2004-01-01

    The paper shows the design of a robust control structure for the speed sensorless vector control of the IM, based on the mixed sensitivity (MS) linear parameter variant (LPV) H8 control theory. The controller makes possible the direct control of the flux and speed of the motor with torque adaptation

  8. Spectral element model for 2-D electrostatic fields in a linear synchronous motor

    van Beek, T.A.; Curti, M.; Jansen, J.W.; Gysen, B.L.J.; Paulides, J.J.H.; Lomonova, E.A.

    2017-01-01

    This paper presents a fast and accurate 2-D spectral element model for analyzing electric field distributions in linear synchronous motors. The electric field distribution is derived using the electric scalar potential for static cases. The spatial potential and electric field distributions obtained

  9. Torque decomposition and control in an iron core linear permanent magnet motor.

    Overboom, T.T.; Smeets, J.P.C.; Stassen, J.M.; Jansen, J.W.; Lomonova, E.

    2012-01-01

    Abstract—This paper concerns the decomposition and control of the torque produced by an iron core linear permanent magnet motor. The proposed method is based on the dq0-decomposition of the three-phase currents using Park’s transformation. The torque is decomposed into a reluctance component and two

  10. Power-optimal force decoupling in a hybrid linear reluctance motor

    Overboom, T.T.; Smeets, J.P.C.; Jansen, J.W.; Lomonova, E.A.; Mavrudieva, D.

    2015-01-01

    This paper concerns the power-optimal decoupling of the propulsion and normal force created by a hybrid linear reluctance motor. The intrinsic limitations to the decoupling is addressed by the visualizing each force component with a quadric surface in the Euclidean space which is spanned by the

  11. Comparison of Thrust Characteristics in Pencil Sized Cylinder-type Linear Motors with Different Magnet Arrays

    Nakaiwa, K; Yamada, A; Tashiro, K; Wakiwaka, H

    2009-01-01

    From a strong demand on the miniaturization of a chip mounter or a semiconductor device, the thrust improvement considering the magnets arrangement is studied. We accept a core stator with a Halbach type magnet array for a current linear motor. The thrust characteristics are compared with two kinds of mover, a NS magnet array and a Halbach magnet array.

  12. Overview of analytical models for the design of linear and planar motors

    Jansen, J.W.; Smeets, J.P.C.; Overboom, T.T.; Rovers, J.M.M.; Lomonova, E.A.

    2014-01-01

    In this paper, an overview of analytical techniques for the modeling of linear and planar permanent-magnet motors is given. These models can be used complementary to finite element analyses for fast evaluations of topologies, but they are indispensable for the design of magnetically levitated planar

  13. Motor properties from persistence: a linear molecular walker lacking spatial and temporal asymmetry

    Zuckermann, Martin J; Forde, Nancy R; Angstmann, Christopher N; Schmitt, Regina; Linke, Heiner; Blab, Gerhard A; Bromley, Elizabeth HC; Curmi, Paul MG

    2015-01-01

    The stepping direction of linear molecular motors is usually defined by a spatial asymmetry of the motor, its track, or both. Here we present a model for a molecular walker that undergoes biased directional motion along a symmetric track in the presence of a temporally symmetric chemical cycle. Instead of using asymmetry, directionality is achieved by persistence. At small load force the walker can take on average thousands of steps in a given direction until it stochastically reverses direction. We discuss a specific experimental implementation of a synthetic motor based on this design and find, using Langevin and Monte Carlo simulations, that a realistic walker can work against load forces on the order of picoNewtons with an efficiency of ∼18%, comparable to that of kinesin. In principle, the walker can be turned into a permanent motor by externally monitoring the walker’s momentary direction of motion, and using feedback to adjust the direction of a load force. We calculate the thermodynamic cost of using feedback to enhance motor performance in terms of the Shannon entropy, and find that it reduces the efficiency of a realistic motor only marginally. We discuss the implications for natural protein motor performance in the context of the strong performance of this design based only on a thermal ratchet. (paper)

  14. Dynamic modeling and characteristics analysis of a modal-independent linear ultrasonic motor.

    Li, Xiang; Yao, Zhiyuan; Zhou, Shengli; Lv, Qibao; Liu, Zhen

    2016-12-01

    In this paper, an integrated model is developed to analyze the fundamental characteristics of a modal-independent linear ultrasonic motor with double piezoelectric vibrators. The energy method is used to model the dynamics of the two piezoelectric vibrators. The interface forces are coupled into the dynamic equations of the two vibrators and the moving platform, forming a whole machine model of the motor. The behavior of the force transmission of the motor is analyzed via the resulting model to understand the drive mechanism. In particular, the relative contact length is proposed to describe the intermittent contact characteristic between the stator and the mover, and its role in evaluating motor performance is discussed. The relations between the output speed and various inputs to the motor and the start-stop transients of the motor are analyzed by numerical simulations, which are validated by experiments. Furthermore, the dead-zone behavior is predicted and clarified analytically using the proposed model, which is also observed in experiments. These results are useful for designing servo control scheme for the motor. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Double-yoke balanced compressor

    Durenec, P.

    1981-01-01

    A double-yoke balanced compressor for a cryogenic cooler that has only linear motion imparted to balanced piston and cylinder masses. A piston yoke is driven in the linear stroke direction by a piston axially offset crankshaft cam and a cylinder yoke is driven linearly by a cylinder axially offset crankshaft cam that is exactly offset 180 0 from the other cam. A large circular bushing in the compressor housing covers the entire outer cylinder head during linear operation to prevent blow by and to guide the cylinder linearly. The lower portion of the piston and cylinder connecting rods fit into linear guides that are further comprised of low molecular weight gas filled cavities to provide additional air bearing smoothness to the linear motion of the piston and cylinder

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

    Hong Junjie, E-mail: hongjjie@mail.sysu.edu.cn [School of Engineering, Sun Yat-Sen University, Guangzhou 510006 (China); Li Liyi, E-mail: liliyi@hit.edu.cn [Dept. Electrical Engineering, Harbin Institute of Technology, Harbin 150000 (China); Zong Zhijian; Liu Zhongtu [School of Engineering, Sun Yat-Sen University, Guangzhou 510006 (China)

    2011-10-15

    Highlights: {yields} The structure of the permanent magnet linear synchronous motor (SW-PMLSM) is new. {yields} A new current control method CEVPC is employed in this motor. {yields} The sectional power supply method is different to the others and effective. {yields} 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.

  17. Unmasking the linear behaviour of slow motor adaptation to prolonged convergence.

    Erkelens, Ian M; Thompson, Benjamin; Bobier, William R

    2016-06-01

    Adaptation to changing environmental demands is central to maintaining optimal motor system function. Current theories suggest that adaptation in both the skeletal-motor and oculomotor systems involves a combination of fast (reflexive) and slow (recalibration) mechanisms. Here we used the oculomotor vergence system as a model to investigate the mechanisms underlying slow motor adaptation. Unlike reaching with the upper limbs, vergence is less susceptible to changes in cognitive strategy that can affect the behaviour of motor adaptation. We tested the hypothesis that mechanisms of slow motor adaptation reflect early neural processing by assessing the linearity of adaptive responses over a large range of stimuli. Using varied disparity stimuli in conflict with accommodation, the slow adaptation of tonic vergence was found to exhibit a linear response whereby the rate (R(2)  = 0.85, P < 0.0001) and amplitude (R(2)  = 0.65, P < 0.0001) of the adaptive effects increased proportionally with stimulus amplitude. These results suggest that this slow adaptive mechanism is an early neural process, implying a fundamental physiological nature that is potentially dominated by subcortical and cerebellar substrates. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. Design and testing of a coaxial linear magnetic spring with integral linear motor. [for spacecraft energy storage

    Patt, P. J.

    1985-01-01

    The design of a coaxial linear magnetic spring which incorporates a linear motor to control axial motion and overcome system damping is presented, and the results of static and dynamic tests are reported. The system has nominal stiffness 25,000 N/m and is designed to oscillate a 900-g component over a 4.6-mm stroke in a Stirling-cycle cryogenic refrigerator being developed for long-service (5-10-yr) space applications (Stolfi et al., 1983). Mosaics of 10 radially magnetized high-coercivity SmCO5 segments enclosed in Ti cans are employed, and the device is found to have quality factor 70-100, corresponding to energy-storage efficiency 91-94 percent. Drawings, diagrams, and graphs are provided.

  19. A superconducting linear motor drive for a positive displacement bellows pump for use in the g-2 cryogenics system

    Green, M.A.

    1994-10-01

    Forced two-phase cooling of indirectly cooled magnets requires circulation of liquid helium through the magnet cooling channel. A bellows helium pump is one possible way of providing helium flow to a magnet cooling system. Since the bellows type of helium pump is immersed in liquid helium, a superconducting linear motor drive appears to be an attractive option. This report describes a linear motor drive that employs oriented permanent magnet materials such as samarium-cobalt as the stator magnet system and a superconducting loud speaker voice coil type of drive as the armature of the linear motor. This report examines drive motor requirements for a helium pump

  20. Universal Linear Motor Driven Leg Press Dynamometer and Concept of Serial Stretch Loading.

    Hamar, Dušan

    2015-08-24

    Paper deals with backgrounds and principles of universal linear motor driven leg press dynamometer and concept of serial stretch loading. The device is based on two computer controlled linear motors mounted to the horizontal rails. As the motors can keep either constant resistance force in selected position or velocity in both directions, the system allows simulation of any mode of muscle contraction. In addition, it also can generate defined serial stretch stimuli in a form of repeated force peaks. This is achieved by short segments of reversed velocity (in concentric phase) or acceleration (in eccentric phase). Such stimuli, generated at the rate of 10 Hz, have proven to be a more efficient means for the improvement of rate of the force development. This capability not only affects performance in many sports, but also plays a substantial role in prevention of falls and their consequences. Universal linear motor driven and computer controlled dynamometer with its unique feature to generate serial stretch stimuli seems to be an efficient and useful tool for enhancing strength training effects on neuromuscular function not only in athletes, but as well as in senior population and rehabilitation patients.

  1. A study on the integration of contactless energy transfer in the end teeth of a PM synchronous linear motor

    Krop, D.C.J.; Lomonova, E.A.; Jansen, J.W.; Paulides, J.J.H.

    2009-01-01

    Linear motors find their utilization in an increasing number of industrial applications. Permanent magnet linear synchronous motors (PMLSMs) are favorable in many applications due to their servo characteristics, robustness, and high force density. The major disadvantage of moving coil type PMLSMs is

  2. Application of an imperialist competitive algorithm to the design of a linear induction motor

    Lucas, Caro; Nasiri-Gheidari, Zahra; Tootoonchian, Farid

    2010-01-01

    In this paper a novel optimization algorithm based on imperialist competitive algorithm (ICA) is used for the design of a low speed single sided linear induction motor (LIM). This type of motors is used increasingly in industrial process specially in transportation systems. In these applications having high efficiency with high power factor is very important. So in this paper the objective function of design is presented considering both efficiency and power factor. Finally the results of ICA are compared with the ones of genetic algorithm and conventional design. Comparison shows the success of ICA for design of LIMs.

  3. Development of sealed nickel-cadmium battery for linear motor car (Maglev). Linear motor car yo Ni-Cd denchi no kaihatsu

    Kono, K; Yoshimura, H; Yufu, H [Yuasa Corp., Osaka (Japan)

    1993-10-29

    Development was made of a linear motor car use battery which is strong in repetition of quick charging/discharging and characterized as follows: Its volumetric energy density is 42Wh/kg which is 1.3 times as high as the conventional one. It excels in high efficiency charging/discharging characteristics. High tension steel sheet is used for it, which is incombustible. To lighten the weight, paste type electrodes and high yield point materials were used for the positive and negative electrodes, and jar materials, respectively. To heighten the charging/discharging characteristics, used were electrodes heightened in current collecting effect. To lengthening the life, unwoven nylon cloth was used as a separator. Also to heighten the thermal discharge characteristics, the electrodes were made metallic with a fitting of cooling fins. The battery characteristics as tested gave the following result: At a capacity ratio of 100%, the discharging factor cleared its target value of development also with a high discharging voltage. The charging/discharging characteristics hardly fall in the high temperature region. The charging characteristics include quick charging made possible. As a result of cyclic simulation presuming the linear motor car, the fall in capacity per cycle was as good as 1.5%. 11 figs., 2 tabs.

  4. Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

    He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

    2018-05-01

    A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

  5. A rectangle-type linear ultrasonic motor using longitudinal vibration transducers with four driving feet.

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2013-04-01

    To make full use of the vibrational energy of a longitudinal transducer, a rectangle-type linear ultrasonic motor with four driving feet is proposed in this paper. This new motor consists of four longitudinal vibration transducers which are arranged in a rectangle and form an enclosed construction. Lead zirconate titanate ceramics are embedded into the middle of the transducer and fastened by a wedge-caulking mechanism. Each transducer includes an exponentially shaped horn located on each end. The horns of the vertical transducers intersect at the base of the horizontal transducers' horns; the tip ends of the horizontal transducers' horns are used as the driving feet. Longitudinal vibrations are superimposed in the motor and generate elliptical movements at the tip ends of the horns. The working principle of the proposed motor is analyzed. The resonance frequencies of two working modes are tuned to be close to each other by adjusting the structural parameters. Transient analysis is developed to gain the vibration characteristics of the motor. A prototype motor is fabricated and measured. The vibration test results verify the feasibility of the proposed design. Typical output of the prototype is a no-load speed of 928 mm/s and maximum thrust force of 60 N at a voltage of 200 Vrms.

  6. Development of an ultrasonic linear motor with ultra-positioning capability and four driving feet.

    Zhu, Cong; Chu, Xiangcheng; Yuan, Songmei; Zhong, Zuojin; Zhao, Yanqiang; Gao, Shuning

    2016-12-01

    This paper presents a novel linear piezoelectric motor which is suitable for rapid ultra-precision positioning. The finite element analysis (FEA) was applied for optimal design and further analysis, then experiments were conducted to investigate its performance. By changing the input signal, the proposed motor was found capable of working in the fast driving mode as well as in the precision positioning mode. When working in the fast driving mode, the motor acts as an ultrasonic motor with maximum no-load speed up to 181.2mm/s and maximum thrust of 1.7N at 200Vp-p. Also, when working in precision positioning mode, the motor can be regarded as a flexible hinge piezoelectric actuator with arbitrary motion in the range of 8μm. The measurable minimum output displacement was found to be 0.08μm, but theoretically, can be even smaller. More importantly, the motor can be quickly and accurately positioned in a large stroke. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Centrifugal compressor design for electrically assisted boost

    Yang, M Y; Martinez-Botas, R F; Zhuge, W L; Qureshi, U; Richards, B

    2013-01-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically

  8. Driving performance of a two-dimensional homopolar linear DC motor

    Wang, Y.; Yamaguchi, M.; Kano, Y. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1998-05-01

    This paper presents a novel two-dimensional homopolar linear de motor (LDM) which can realize two-dimensional (2-D) motion. For position control purposes, two kinds of position detecting methods are proposed. The position in one position is detected by means of a capacitive sensor which makes the output of the sensor partially immune to the variation of the gap between electrodes. The position in the other direction is achieved by exploiting the position dependent property of the driving coil inductance, instead of using an independent sensor. The position control is implemented on the motor and 2-D tracking performance is analyzed. Experiments show that the motor demonstrates satisfactory driving performance, 2-D tracking error being within 5.5% when the angular frequency of reference signal is 3.14 rad./s. 7 refs., 17 figs., 2 tabs.

  9. Innervation zones of fasciculating motor units: observations by a linear electrode array.

    Jahanmiri-Nezhad, Faezeh; Barkhaus, Paul E; Rymer, William Z; Zhou, Ping

    2015-01-01

    This study examines the innervation zone (IZ) in the biceps brachii muscle in healthy subjects and those with amyotrophic lateral sclerosis (ALS) using a 20-channel linear electromyogram (EMG) electrode array. Raster plots of individual waveform potentials were studied to estimate the motor unit IZ. While this work mainly focused on fasciculation potentials (FPs), a limited number of motor unit potentials (MUPs) from voluntary activity of 12 healthy and seven ALS subjects were also examined. Abnormal propagation of MUPs and scattered IZs were observed in fasciculating units, compared with voluntarily activated MUPs in healthy and ALS subjects. These findings can be related to muscle fiber reinnervation following motor neuron degeneration in ALS and the different origin sites of FPs compared with voluntary MUPs.

  10. Torque ripple reduction of brushless DC motor based on adaptive input-output feedback linearization.

    Shirvani Boroujeni, M; Markadeh, G R Arab; Soltani, J

    2017-09-01

    Torque ripple reduction of Brushless DC Motors (BLDCs) is an interesting subject in variable speed AC drives. In this paper at first, a mathematical expression for torque ripple harmonics is obtained. Then for a non-ideal BLDC motor with known harmonic contents of back-EMF, calculation of desired reference current amplitudes, which are required to eliminate some selected harmonics of torque ripple, are reviewed. In order to inject the reference harmonic currents to the motor windings, an Adaptive Input-Output Feedback Linearization (AIOFBL) control is proposed, which generates the reference voltages for three phases voltage source inverter in stationary reference frame. Experimental results are presented to show the capability and validity of the proposed control method and are compared with the vector control in Multi-Reference Frame (MRF) and Pseudo-Vector Control (P-VC) method results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. High Precision Piezoelectric Linear Motors for Operations at Cryogenic Temperatures and Vacuum

    Wong, D.; Carman, G.; Stam, M.; Bar-Cohen, Y.; Sen, A.; Henry, P.; Bearman, G.; Moacanin, J.

    1995-01-01

    The Jet Propulsion Laboratory evaluated the use of an electromechanical device for optically positioning a mirror system during the pre-project phase of the Pluto-Fast-Flyby (PFF) mission. The device under consideration was a piezoelectric driven linear motor functionally dependent upon a time varying electric field which induces displacements ranging from submicrons to millimeters with positioning accuracy within nanometers. Using a control package, the mirror system provides image motion compensation and mosaicking capabilities. While this device offers unique advantages, there were concerns pertaining to its operational capabilities for the PFF mission. The issues include irradiation effects and thermal concerns. A literature study indicated that irradiation effects will not significantly impact the linear motor's operational characteristics. On the other hand, thermal concerns necessitated an in depth study.

  12. Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

    Studer, P. A. (Inventor)

    1982-01-01

    A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

  13. Design and experiments of a linear piezoelectric motor driven by a single mode.

    Liu, Zhen; Yao, Zhiyuan; Li, Xiang; Fu, Qianwei

    2016-11-01

    In this contribution, we propose a novel linear piezoelectric motor with a compact stator that is driven by a single mode. The linear piezoelectric motor can realize bidirectional motion by changing the vibration modes of the stator. Finite element analysis is performed to determine the required vibration mode of the stator and obtain the optimal stator structure and dimensions. Furthermore, the trajectories of the driving foot are analyzed with and without consideration of the mechanical contact with the slider. It is shown that the trajectory of the driving foot is an oblique line when disregarding the contact, and the trajectory becomes an oblique ellipse while taking into account the contact. Finally, a prototype of the motor is fabricated based on the results of finite element analysis. The optimization results show that the motor reaches its maximum thrust force of 4.0 kg, maximum thrust-weight ratio of 33.3, maximum unloaded velocity of 385 mm/s under the excitation of Mode-B, and maximum unloaded velocity of 315 mm/s under the excitation of Mode-L.

  14. Evaluation of linear DC motor actuators for control of large space structures

    Ide, Eric Nelson

    1988-01-01

    This thesis examines the use of a linear DC motor as a proof mass actuator for the control of large space structures. A model for the actuator, including the current and force compensation used, is derived. Because of the force compensation, the actuator is unstable when placed on a structure. Relative position feedback is used for actuator stabilization. This method of compensation couples the actuator to the mast in a feedback configuration. Three compensator designs are prop...

  15. Computer-aided design studies of the homopolar linear synchronous motor

    Dawson, G. E.; Eastham, A. R.; Ong, R.

    1984-09-01

    The linear induction motor (LIM), as an urban transit drive, can provide good grade-climbing capabilities and propulsion/braking performance that is independent of steel wheel-rail adhesion. In view of its 10-12 mm airgap, the LIM is characterized by a low power factor-efficiency product of order 0.4. A synchronous machine offers high efficiency and controllable power factor. An assessment of the linear homopolar configuration of this machine is presented as an alternative to the LIM. Computer-aided design studies using the finite element technique have been conducted to identify a suitable machine design for urban transit propulsion.

  16. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  17. Electrohydraulic linear actuator with two stepping motors controlled by overshoot-free algorithm

    Milecki, Andrzej; Ortmann, Jarosław

    2017-11-01

    The paper describes electrohydraulic spool valves with stepping motors used as electromechanical transducers. A new concept of a proportional valve in which two stepping motors are working differentially is introduced. Such valve changes the fluid flow proportionally to the sum or difference of the motors' steps numbers. The valve design and principle of its operation is described. Theoretical equations and simulation models are proposed for all elements of the drive, i.e., the stepping motor units, hydraulic valve and cylinder. The main features of the valve and drive operation are described; some specific problem areas covering the nature of stepping motors and their differential work in the valve are also considered. The whole servo drive non-linear model is proposed and used further for simulation investigations. The initial simulation investigations of the drive with a new valve have shown that there is a significant overshoot in the drive step response, which is not allowed in positioning process. Therefore additional effort is spent to reduce the overshoot and in consequence reduce the settling time. A special predictive algorithm is proposed to this end. Then the proposed control method is tested and further improved in simulations. Further on, the model is implemented in reality and the whole servo drive system is tested. The investigation results presented in this paper, are showing an overshoot-free positioning process which enables high positioning accuracy.

  18. Driver electronics design and control for a total artificial heart linear motor.

    Unthan, Kristin; Cuenca-Navalon, Elena; Pelletier, Benedikt; Finocchiaro, Thomas; Steinseifer, Ulrich

    2018-01-27

    For any implantable device size and efficiency are critical properties. Thus, a linear motor for a Total Artificial Heart was optimized with focus on driver electronics and control strategies. Hardware requirements were defined from power supply and motor setup. Four full bridges were chosen for the power electronics. Shunt resistors were set up for current measurement. Unipolar and bipolar switching for power electronics control were compared regarding current ripple and power losses. Here, unipolar switching showed smaller current ripple and required less power to create the necessary motor forces. Based on calculations for minimal power losses Lorentz force was distributed to the actor's four coils. The distribution was determined as ratio of effective magnetic flux through each coil, which was captured by a force test rig. Static and dynamic measurements under physiological conditions analyzed interaction of control and hardware and all efficiencies were over 89%. In conclusion, the designed electronics, optimized control strategy and applied current distribution create the required motor force and perform optimal under physiological conditions. The developed driver electronics and control offer optimized size and efficiency for any implantable or portable device with multiple independent motor coils. Graphical Abstract ᅟ.

  19. Influence of a high vacuum on the precise positioning using an ultrasonic linear motor.

    Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

    2011-01-01

    This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

  20. Influence of a high vacuum on the precise positioning using an ultrasonic linear motor

    Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

    2011-01-01

    This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

  1. CONFIRMATION OF THE MATHEMATICAL MODEL ADEQUACY OF A LINEAR SYNCHRONOUS MOTOR

    V. F. Novikov

    2015-06-01

    Full Text Available Purpose.To reduce labor costs and the amount of computer time in the design of linear synchronous motors with excitation from a source of a constant magnetic field of high-speed ground transportation it is necessary to use engineering methods. The purpose of this study is to confirm the adequacy of the previously proposed mathematical model of this engine and assumptions. It is also intended to confirm the possibility of applying the method of calculation of traction that occurs in the engine in the interaction of the permanent magnetic field of the excitation system of a vehicle with a coil track structure.Methodology. As for empirical theories the positive result of the experiment is not absolute proof of the truth, for an unambiguous conclusion about the adequacy of the developed model and the effectiveness of the developed methods need to be tested for falsification. In accordance with this criterion, it is necessary to conduct an experiment, the results of which will coincide with the calculation but you also need to avoid errors caused by random coincidences. For this purpose the experiments with varying parameters are conducted. Findings. In a critical experiment configuration changes of the excitation system were held so that the shape dependence of traction from displacement is differed significantly. The comparison of the results of the calculated and experimental values of traction for different configurations showed that the differences are minor and easily explained by measurement error and uneven gaps between the poles and excitation coils of the track structure. Originality. The adequacy of the mathematical model of a linear synchronous motor without a ferromagnetic magnetic circuit and the assumptions and applicability of the calculation method of traction forces involved in it, at the interaction of a permanent magnetic field of the excitation system of a vehicle with a coil track structure were proved. This proof is built on

  2. Supersonic compressor

    Roberts, II, William Byron; Lawlor, Shawn P.; Breidenthal, Robert E.

    2016-04-12

    A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  3. Magnetically Suspended Linear Pulse Motor for Semiconductor Wafer Transfer in Vacuum Chamber

    Moriyama, Shin-Ichi; Hiraki, Naoji; Watanabe, Katsuhide; Kanemitsu, Yoichi

    1996-01-01

    This paper describes a magnetically suspended linear pulse motor for a semiconductor wafer transfer robot in a vacuum chamber. The motor can drive a wafer transfer arm horizontally without mechanical contact. In the construction of the magnetic suspension system, four pairs of linear magnetic bearings for the lift control are used for the guidance control as well. This approach allows us to make the whole motor compact in size and light in weight. The tested motor consists of a double-sided stator and a transfer arm with a width of 50 mm and a total length of 700 mm. The arm, like a ladder in shape, is designed as the floating element with a tooth width of 4 mm (a tooth pitch of 8 mm). The mover mass is limited to about 1.6 kg by adopting such an arm structure, and the ratio of thrust to mover mass reaches to 3.2 N/kg under a broad air gap (1 mm) between the stator teeth and the mover teeth. The performance testing was carried out with a transfer distance less than 450 mm and a transfer speed less than 560 mm/s. The attitude of the arm was well controlled by the linear magnetic bearings with a combined use, and consequently the repeatability on the positioning of the arm reached to about 2 micron. In addition, the positioning accuracy was improved up to about 30 micron through a compensation of the 128-step wave current which was used for the micro-step drive with a step increment of 62.5 micron.

  4. Novel permanent magnet linear motor with isolated movers: analytical, numerical and experimental study.

    Yan, Liang; Peng, Juanjuan; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-10-01

    This paper proposes a novel permanent magnet linear motor possessing two movers and one stator. The two movers are isolated and can interact with the stator poles to generate independent forces and motions. Compared with conventional multiple motor driving system, it helps to increase the system compactness, and thus improve the power density and working efficiency. The magnetic field distribution is obtained by using equivalent magnetic circuit method. Following that, the formulation of force output considering armature reaction is carried out. Then inductances are analyzed with finite element method to investigate the relationships of the two movers. It is found that the mutual-inductances are nearly equal to zero, and thus the interaction between the two movers is negligible. A research prototype of the linear motor and a measurement apparatus on thrust force have been developed. Both numerical computation and experiment measurement are conducted to validate the analytical model of thrust force. Comparison shows that the analytical model matches the numerical and experimental results well.

  5. Bond Graph Modelling for Fault Detection and Isolation of an Ultrasonic Linear Motor

    Mabrouk KHEMLICHE

    2010-12-01

    Full Text Available In this paper Bond Graph modeling, simulation and monitoring of ultrasonic linear motors are presented. Only the vibration of piezoelectric ceramics and stator will be taken into account. Contact problems between stator and rotor are not treated here. So, standing and travelling waves will be briefly presented since the majority of the motors use another wave type to generate the stator vibration and thus obtain the elliptic trajectory of the points on the surface of the stator in the first time. Then, electric equivalent circuit will be presented with the aim for giving a general idea of another way of graphical modelling of the vibrator introduced and developed. The simulations of an ultrasonic linear motor are then performed and experimental results on a prototype built at the laboratory are presented. Finally, validation of the Bond Graph method for modelling is carried out, comparing both simulation and experiment results. This paper describes the application of the FDI approach to an electrical system. We demonstrate the FDI effectiveness with real data collected from our automotive test. We introduce the analysis of the problem involved in the faults localization in this process. We propose a method of fault detection applied to the diagnosis and to determine the gravity of a detected fault. We show the possibilities of application of the new approaches to the complex system control.

  6. Optimization and Analysis of a U-Shaped Linear Piezoelectric Ultrasonic Motor Using Longitudinal Transducers.

    Yu, Hongpeng; Quan, Qiquan; Tian, Xinqi; Li, He

    2018-03-07

    A novel U-shaped piezoelectric ultrasonic motor that mainly focused on miniaturization and high power density was proposed, fabricated, and tested in this work. The longitudinal vibrations of the transducers were excited to form the elliptical movements on the driving feet. Finite element method (FEM) was used for design and analysis. The resonance frequencies of the selected vibration modes were tuned to be very close to each other with modal analysis and the movement trajectories of the driving feet were gained with transient simulation. The vibration modes and the mechanical output abilities were tested to evaluate the proposed motor further by a prototype. The maximum output speed was tested to be 416 mm/s, the maximum thrust force was 21 N, and the maximum output power was 5.453 W under frequency of 29.52 kHz and voltage of 100 V rms . The maximum output power density of the prototype reached 7.59 W/kg, which was even greater than a previous similar motor under the exciting voltage of 200 V rms . The proposed motor showed great potential for linear driving of large thrust force and high power density.

  7. Population decoding of motor cortical activity using a generalized linear model with hidden states.

    Lawhern, Vernon; Wu, Wei; Hatsopoulos, Nicholas; Paninski, Liam

    2010-06-15

    Generalized linear models (GLMs) have been developed for modeling and decoding population neuronal spiking activity in the motor cortex. These models provide reasonable characterizations between neural activity and motor behavior. However, they lack a description of movement-related terms which are not observed directly in these experiments, such as muscular activation, the subject's level of attention, and other internal or external states. Here we propose to include a multi-dimensional hidden state to address these states in a GLM framework where the spike count at each time is described as a function of the hand state (position, velocity, and acceleration), truncated spike history, and the hidden state. The model can be identified by an Expectation-Maximization algorithm. We tested this new method in two datasets where spikes were simultaneously recorded using a multi-electrode array in the primary motor cortex of two monkeys. It was found that this method significantly improves the model-fitting over the classical GLM, for hidden dimensions varying from 1 to 4. This method also provides more accurate decoding of hand state (reducing the mean square error by up to 29% in some cases), while retaining real-time computational efficiency. These improvements on representation and decoding over the classical GLM model suggest that this new approach could contribute as a useful tool to motor cortical decoding and prosthetic applications. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  8. Population Decoding of Motor Cortical Activity using a Generalized Linear Model with Hidden States

    Lawhern, Vernon; Wu, Wei; Hatsopoulos, Nicholas G.; Paninski, Liam

    2010-01-01

    Generalized linear models (GLMs) have been developed for modeling and decoding population neuronal spiking activity in the motor cortex. These models provide reasonable characterizations between neural activity and motor behavior. However, they lack a description of movement-related terms which are not observed directly in these experiments, such as muscular activation, the subject's level of attention, and other internal or external states. Here we propose to include a multi-dimensional hidden state to address these states in a GLM framework where the spike count at each time is described as a function of the hand state (position, velocity, and acceleration), truncated spike history, and the hidden state. The model can be identified by an Expectation-Maximization algorithm. We tested this new method in two datasets where spikes were simultaneously recorded using a multi-electrode array in the primary motor cortex of two monkeys. It was found that this method significantly improves the model-fitting over the classical GLM, for hidden dimensions varying from 1 to 4. This method also provides more accurate decoding of hand state (lowering the Mean Square Error by up to 29% in some cases), while retaining real-time computational efficiency. These improvements on representation and decoding over the classical GLM model suggest that this new approach could contribute as a useful tool to motor cortical decoding and prosthetic applications. PMID:20359500

  9. A Low Mass Translation Mechanism for Planetary FTIR Spectrometry using an Ultrasonic Piezo Linear Motor

    Heverly, Matthew; Dougherty, Sean; Toon, Geoffrey; Soto, Alejandro; Blavier, Jean-Francois

    2004-01-01

    One of the key components of a Fourier Transform Infrared Spectrometer (FTIR) is the linear translation stage used to vary the optical path length between the two arms of the interferometer. This translation mechanism must produce extremely constant velocity motion across its entire range of travel to allow the instrument to attain high signal-to-noise ratio and spectral resolving power. A new spectrometer is being developed at the Jet Propulsion Laboratory under NASA s Planetary Instrument Definition and Development Program (PIDDP). The goal of this project is to build upon existing spaceborne FTIR spectrometer technology to produce a new instrument prototype that has drastically superior spectral resolution and substantially lower mass, making it feasible for planetary exploration. In order to achieve these goals, Alliance Spacesystems, Inc. (ASI) has developed a linear translation mechanism using a novel ultrasonic piezo linear motor in conjunction with a fully kinematic, fault tolerant linear rail system. The piezo motor provides extremely smooth motion, is inherently redundant, and is capable of producing unlimited travel. The kinematic rail uses spherical Vespel(R). rollers and bushings, which eliminates the need for wet lubrication, while providing a fault tolerant platform for smooth linear motion that will not bind under misalignment or structural deformation. This system can produce velocities from 10 - 100 mm/s with less than 1% velocity error over the entire 100-mm length of travel for a total mechanism mass of less than 850 grams. This system has performed over half a million strokes under vacuum without excessive wear or degradation in performance. This paper covers the design, development, and testing of this linear translation mechanism as part of the Planetary Atmosphere Occultation Spectrometer (PAOS) instrument prototype development program.

  10. Direct torque and flux regulation of synchronous reluctance motor drives based on input-output feedback linearization

    Abootorabi Zarchi, H.; Arab Markadeh, Gh.R.; Soltani, J.

    2010-01-01

    In this paper, a nonlinear speed tracking controller is introduced for three-phase synchronous reluctance motor (SynRM) on the basis of input-output feedback linearization (IOFL), considering the different control strategies (maximum torque per Ampere, high efficiency and minimum KVA rating for the inverter) related to this motor. The proposed control approach is capable of decoupling control of stator flux and motor generated torque. The validity and effectiveness of the method is verified by simulation and experimental results.

  11. Pole-shape optimization of permanent-magnet linear synchronous motor for reduction of thrust ripple

    Tavana, Nariman Roshandel, E-mail: nroshandel@ee.iust.ac.i [Department of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Shoulaie, Abbas, E-mail: shoulaie@iust.ac.i [Department of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of)

    2011-01-15

    In this paper, we have used magnet arc shaping technique in order to improve the performance of permanent-magnet linear synchronous motor (PMLSM). At first, a detailed analytical modeling based on Maxwell equations is presented for the analysis and design of PMLSM with the arc-shaped magnetic poles (ASMPs). Then the accuracy of presented method is verified by finite-element method. Very close agreement between the analytical and finite-element results shows the effectiveness of the proposed method. Finally, a magnet shape design is carried out based on the analytical method to enhance the motor developed thrust. Pertinent evaluations on the optimal design performance demonstrate that shape optimization leads to a design with extra low thrust ripple.

  12. Dynamic diagnostics of moving ferromagnetic material with the linear induction motor

    Szewczyk Krzysztof

    2017-01-01

    Full Text Available The paper presents the application of a three-phase induction motor as a sensor measuring the force of the electromagnetic field connection between the engine and produced sheet steel. The force interaction between the engine and the manufactured sheet metal treated as a treadmill for a linear motor may be an indicator of damage to the material. Detection of places where the sheet does not meet the quality requirements may be very useful in the production process. FEM calculations were performed in the ANSYS MAXWELL environment. The results suggest the possibility of using this type of construction to test the quality of produced materials. The computational results and their analysis are presented in this article.

  13. Adaptive H∞ nonlinear velocity tracking using RBFNN for linear DC brushless motor

    Tsai, Ching-Chih; Chan, Cheng-Kain; Li, Yi Yu

    2012-01-01

    This article presents an adaptive H ∞ nonlinear velocity control for a linear DC brushless motor. A simplified model of this motor with friction is briefly recalled. The friction dynamics is described by the Lu Gre model and the online tuning radial basis function neural network (RBFNN) is used to parameterise the nonlinear friction function and un-modelled errors. An adaptive nonlinear H ∞ control method is then proposed to achieve velocity tracking, by assuming that the upper bounds of the ripple force, the changeable load and the nonlinear friction can be learned by the RBFNN. The closed-loop system is proven to be uniformly bounded using the Lyapunov stability theory. The feasibility and the efficacy of the proposed control are exemplified by conducting two velocity tracking experiments.

  14. An electrostatic 3-phase linear stepper motor fabricated by vertical trench isolation technology

    Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Fujita, Hiroyuki

    2009-01-01

    We present the design, microfabrication and characterization of an electrostatic 3-phase linear stepper micromotor constructed with vertical trench isolation technology. This suitable technology was used to create a monolithic stepper motor with high-aspect-ratio poles and an integrated 3-phase electrical network in the bulk of a standard single-crystal silicon wafer. The shuttle of the stepper motor is suspended by a flexure to avoid any mechanical contact during operation, enhancing the precision, repeatability and reliability of the stepping motion. The prototype is capable of a maximum travel of +/−26 µm (52 µm) at an actuation voltage of 30 V and a step size of 1.4 µm during a half-stepping sequence

  15. An electrostatic 3-phase linear stepper motor fabricated by vertical trench isolation technology

    Sarajlic, Edin; Yamahata, Christophe; Cordero, Mauricio; Fujita, Hiroyuki

    2009-07-01

    We present the design, microfabrication and characterization of an electrostatic 3-phase linear stepper micromotor constructed with vertical trench isolation technology. This suitable technology was used to create a monolithic stepper motor with high-aspect-ratio poles and an integrated 3-phase electrical network in the bulk of a standard single-crystal silicon wafer. The shuttle of the stepper motor is suspended by a flexure to avoid any mechanical contact during operation, enhancing the precision, repeatability and reliability of the stepping motion. The prototype is capable of a maximum travel of +/-26 µm (52 µm) at an actuation voltage of 30 V and a step size of 1.4 µm during a half-stepping sequence. This work was presented in part at the 19th MicroMechanics Europe Workshop (MME), 28-30 September 2008, Aachen, Germany.

  16. A linear motor and compact cylinder-piston driver for left ventricular bypass.

    Qian, K X

    1990-01-01

    A simple, portable, reliable and noise-free pneumatic driver has been developed. It consists of a linear motor attached to a cylinder piston, in one unit. The motor coil is directly wound on the cylinder, and the permanent magnet is fixed to the piston. As a continuous voltage square wave is applied to the coil, the cylinder reciprocates on the piston periodically, producing air pressure and vacuum alternately. In conjunction with a locally made diaphragm pump, the driver was tested in vitro and in vivo. Results demonstrated that the device could drive the diaphragm pump and so support the circulation of an experimental animal. The driver weighs 12 kg. For 200 mmHg air pressure and -80 mmHg vacuum the power consumed is 30 W. Its noise is about 30 dB, less than that of an artificial valve and pump.

  17. Pole-shape optimization of permanent-magnet linear synchronous motor for reduction of thrust ripple

    Tavana, Nariman Roshandel; Shoulaie, Abbas

    2011-01-01

    In this paper, we have used magnet arc shaping technique in order to improve the performance of permanent-magnet linear synchronous motor (PMLSM). At first, a detailed analytical modeling based on Maxwell equations is presented for the analysis and design of PMLSM with the arc-shaped magnetic poles (ASMPs). Then the accuracy of presented method is verified by finite-element method. Very close agreement between the analytical and finite-element results shows the effectiveness of the proposed method. Finally, a magnet shape design is carried out based on the analytical method to enhance the motor developed thrust. Pertinent evaluations on the optimal design performance demonstrate that shape optimization leads to a design with extra low thrust ripple.

  18. Magnetically levitated railway with common reaction rail for a linear motor drive and an electro dynamic side guidance arrangement

    Friedrich, R

    1977-04-07

    The invention concerns a magnetically levitated railway with common reaction rail for the linear motor drive and the electrical side guidance arrangement. While the electro-dynamic hovering process requires a high electrical conductivity of the reaction rails in order to reduce eddy current losses, these should show a relatively high resistance for the asynchronous linear motor to reduce losses of propelling force. These contradictory requirements can be fulfilled for a common reaction rail made of homogeneous material of high electrical conductivity according to the invention, by providing slits at right angles to the driving axis in the part of the reaction rail allocated to the linear motor. Thus the guidance system retains a low ohmic resistance, while the part of the reaction rail allocated to the windings of the linear motor has a relatively low ohmic secondary resistance, by which the border and end effects which reduce the propelling force can be appreciably reduced.

  19. Simulation of magnetic induction distribution in a coaxial linear motor with axial and radial direction of permanent magnets magnetization

    G.M. Golenkov

    2014-03-01

    Full Text Available The paper presents results of computer simulation and experimental study of magnetic induction distribution in a coaxial linear motor air gap throughout the length of the runner active part at different heights of the air gap between the runner and the inductor magnetic core for motors with axial and radial direction of the permanent magnets magnetization.

  20. Air-gap field, induced voltage and thrust in the short-stator linear induction motor

    Deleroi, W

    1980-07-15

    The description of the magnetic field in the air-gap of a short-primary linear induction motor, and the subsequent calculation of the thrust developed and the voltages induced in the stator bars can be made by using balancing waves. These balancing waves are generated at any point where the field wave that would exist in a machine of infinite length is disturbed. In the linear motor these disturbances occur at the ends of the stator iron and at discontinuities in the distribution of the stator winding, which exist in machines having stepped windings. From the points where they are generated, free balancing waves travel in two directions and determine the performance of these machines to a large extent. The voltage they induce in a stator bar can be determined from the core flux and mapped on a phasor diagram. The resulting voltage phasor follows a logarithmic spiral. The resulting voltages induced in the three phase windings form a strongly asymmetrical system which can be split-up into positive-, negative- and zerosequence components depending on the slip. The tangential forces may be calculated as the product of the magnetic flux density in the air-gap and the linear current density in either the stator or the reaction rail. As the 'magnetic tail' outside the machine also gives rise to forces in the direction of motion, both methods yield quite different force distributions, though for the resulting force the same value is found.

  1. Design of small centrifugal compressor test model for a supercritical CO2 compressor in the fast reactor power plant

    Muto, Y.; Ishizuka, T.; Aritomi, M.

    2008-01-01

    In order to clarify the CO 2 compressor performance in the vicinity of critical point, a research project has been started in Tokyo Institute of Technology based on Japanese government fund. This paper describes how fundamental parameters were selected and sizing of a small and high speed impeller of the test centrifugal compressor. The concept of canned type compressor structures provided with high speed electric motor and preliminary aerodynamic performance prediction are also given. (authors)

  2. Dual capacity reciprocating compressor

    Wolfe, Robert W.

    1984-01-01

    A multi-cylinder compressor 10 particularly useful in connection with northern climate heat pumps and in which different capacities are available in accordance with reversing motor 16 rotation is provided with an eccentric cam 38 on a crank pin 34 under a fraction of the connecting rods, and arranged for rotation upon the crank pin between opposite positions 180.degree. apart so that with cam rotation on the crank pin such that the crank throw is at its normal maximum value all pistons pump at full capacity, and with rotation of the crank shaft in the opposite direction the cam moves to a circumferential position on the crank pin such that the overall crank throw is zero. Pistons 24 whose connecting rods 30 ride on a crank pin 36 without a cam pump their normal rate with either crank rotational direction. Thus a small clearance volume is provided for any piston that moves when in either capacity mode of operation.

  3. An alternative compressor. A study; Alternativ kompressor. En udredning

    Dall, O.; Jensen, F.; Danig, P.O.; Ritchie, E.; Kierkegaard, P.

    1997-10-01

    A linear compressor would be suitable for refrigerating systems with small effect. A computerized control system can be used to control the speed of a linear engine. A new compressor/engine with much improved energy efficiency can be designed to operate oil-free. The novel design of a compressor with smaller piston displacement is smaller than the existing models and thus more suitable for the future refrigerators. (EG) EFP-97. 71 refs.

  4. A study on stable levitation of permanent magnet transportation system with coreless linear synchronous motor

    Hiwaki, H [Dept. of Electrical and Electronic Engineering, Musashi Inst. of Technology, Tokyo (Japan); Watada, M [Dept. of Electrical and Electronic Engineering, Musashi Inst. of Technology, Tokyo (Japan); Torii, S [Dept. of Electrical and Electronic Engineering, Musashi Inst. of Technology, Tokyo (Japan); Ebihara, D [Dept. of Electrical and Electronic Engineering, Musashi Inst. of Technology, Tokyo (Japan)

    1996-12-31

    In the permanent magnet levitation system, it is impossible to stabilize the motion of the vehicle in both levitation and guidance directions only by permanent magnet. Therefore, the authors proposed the combined system of permanent magnet for levitation and coreless linear synchronous motor (coreless LSM). To design the coreless coils for LSM, the method to calculate the spring coefficient between coreless coil and permanent magnet for LSM is shown. By using this method, the spring coefficients of the three coil arrangements are compared and coreless coil is designed. Furthermore, the authors showed the possibility of stabilizing the motion of the levitation system with coreless LSM. (orig.)

  5. A new double sided linear switched reluctance motor with low cost

    Daldaban, Ferhat; Ustkoyuncu, Nurettin

    2006-01-01

    This paper presents the realization and design of a new linear switched reluctance motor (LSRM) structure. The new model has double sided configuration and provides high force for many applications with low cost. The characteristics of the LSRM are obtained by using finite element analysis (FEA) and analytical calculations. The results of the FEA and analytical calculations are presented, and compared with experimental results. A high correlation between experimental and analytical results is obtained, which has been demonstrated in the form of inductance versus position versus current

  6. Experimental Analysis of Linear Induction Motor under Variable Voltage Variable Frequency (VVVF Power Supply

    Prasenjit D. Wakode

    2016-07-01

    Full Text Available This paper presents the complete analysis of Linear Induction Motor (LIM under VVVF. The complete variation of LIM air gap flux under ‘blocked Linor’ condition and starting force is analyzed and presented when LIM is given VVVF supply. The analysis of this data is important in further understanding of the equivalent circuit parameters of LIM and to study the magnetic circuit of LIM. The variation of these parameters is important to know the LIM response at different frequencies. The simulation and application of different control strategies such as vector control thus becomes quite easy to apply and understand motor’s response under such strategy of control.

  7. Decentralized control of the COFS-I Mast using linear dc motors

    Lindner, Douglas K.; Celano, Tom; Ide, Eric

    1989-01-01

    Consideration is given to a decentralized control design for vibration suppression in the COFS-I Mast using linear dc motors for actuators. The decentralized control design is based results from power systems using root locus techniques that are not well known. The approach is effective because the loop gain is low due to low actuator authority. The frequency-dependent nonlinearities of the actuator are taken into account. Because of the tendency of the transients to saturate the the stroke length of the actuator, its effectiveness is limited.

  8. Incremental Adaptive Fuzzy Control for Sensorless Stroke Control of A Halbach-type Linear Oscillatory Motor

    Lei, Meizhen; Wang, Liqiang

    2018-01-01

    The halbach-type linear oscillatory motor (HT-LOM) is multi-variable, highly coupled, nonlinear and uncertain, and difficult to get a satisfied result by conventional PID control. An incremental adaptive fuzzy controller (IAFC) for stroke tracking was presented, which combined the merits of PID control, the fuzzy inference mechanism and the adaptive algorithm. The integral-operation is added to the conventional fuzzy control algorithm. The fuzzy scale factor can be online tuned according to the load force and stroke command. The simulation results indicate that the proposed control scheme can achieve satisfied stroke tracking performance and is robust with respect to parameter variations and external disturbance.

  9. Improvement of superconducting cylindrical linear induction motor; Chodendo entokeitan ichiji rinia yudo mota no tokusei kaizen

    Kikuma, T.; Tomita, M.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)

    1999-11-10

    For the purpose of we examining the effect of characteristics and ac loss under real machine operating environment of the alternating current superconductivity winding for a realization of the superconductive AC machine vessel, cylindrical shortness first linear guiding motor which used NbTi/CuNi superconducting cable for the primary winding was produced experimentally. The coil number was increased from 6 in 14 this time, and the optimization of the primary current was done, and the improvement on characteristics was attempted. Here, starting torque characteristics, quenching detection protection control circuit are reported. (NEDO)

  10. Particle Swarm Based Approach of a Real-Time Discrete Neural Identifier for Linear Induction Motors

    Alma Y. Alanis

    2013-01-01

    Full Text Available This paper focusses on a discrete-time neural identifier applied to a linear induction motor (LIM model, whose model is assumed to be unknown. This neural identifier is robust in presence of external and internal uncertainties. The proposed scheme is based on a discrete-time recurrent high-order neural network (RHONN trained with a novel algorithm based on extended Kalman filter (EKF and particle swarm optimization (PSO, using an online series-parallel con…figuration. Real-time results are included in order to illustrate the applicability of the proposed scheme.

  11. High Efficiency Pneumatic Systems Compressors Hydrodynamics and Termodynamics Process Research

    Paulius Bogdevičius

    2016-12-01

    Full Text Available The paper analyzes pneumatic system, which consists of three piston compressors, pipes and reciever. Designed two cylinder piston compressor with an asynchronous electric motor mathematical model. In the mathematical model has been estimated rod mechanism geometry and kinematic parameters also hudrodynamics and thermodynamic processes going in the cylinders. Also there were made mathematical experiment and presented the results of it.

  12. Automatic Human Movement Assessment With Switching Linear Dynamic System: Motion Segmentation and Motor Performance.

    de Souza Baptista, Roberto; Bo, Antonio P L; Hayashibe, Mitsuhiro

    2017-06-01

    Performance assessment of human movement is critical in diagnosis and motor-control rehabilitation. Recent developments in portable sensor technology enable clinicians to measure spatiotemporal aspects to aid in the neurological assessment. However, the extraction of quantitative information from such measurements is usually done manually through visual inspection. This paper presents a novel framework for automatic human movement assessment that executes segmentation and motor performance parameter extraction in time-series of measurements from a sequence of human movements. We use the elements of a Switching Linear Dynamic System model as building blocks to translate formal definitions and procedures from human movement analysis. Our approach provides a method for users with no expertise in signal processing to create models for movements using labeled dataset and later use it for automatic assessment. We validated our framework on preliminary tests involving six healthy adult subjects that executed common movements in functional tests and rehabilitation exercise sessions, such as sit-to-stand and lateral elevation of the arms and five elderly subjects, two of which with limited mobility, that executed the sit-to-stand movement. The proposed method worked on random motion sequences for the dual purpose of movement segmentation (accuracy of 72%-100%) and motor performance assessment (mean error of 0%-12%).

  13. The Experimental Study of Rayleigh-Taylor Instability using a Linear Induction Motor Accelerator

    Yamashita, Nicholas; Jacobs, Jeffrey

    2009-11-01

    The experiments to be presented utilize an incompressible system of two stratified miscible liquids of different densities that are accelerated in order to produce the Rayleigh-Taylor instability. Three liquid combinations are used: isopropyl alcohol with water, a calcium nitrate solution or a lithium polytungstate solution, giving Atwood numbers of 0.11, 0.22 and 0.57, respectively. The acceleration required to drive the instability is produced by two high-speed linear induction motors mounted to an 8 m tall drop tower. The motors are mounted in parallel and have an effective acceleration length of 1.7 m and are each capable of producing 15 kN of thrust. The liquid system is contained within a square acrylic tank with inside dimensions 76 x76x184 mm. The tank is mounted to an aluminum plate, which is driven by the motors to create constant accelerations in the range of 1-20 g's, though the potential exists for higher accelerations. Also attached to the plate are a high-speed camera and an LED backlight to provide continuous video of the instability. In addition, an accelerometer is used to provide acceleration measurements during each experiment. Experimental image sequences will be presented which show the development of a random three-dimensional instability from an unforced initial perturbation. Measurements of the mixing zone width will be compared with traditional growth models.

  14. Centrifugal Compressor Surge Controlled

    Skoch, Gary J.

    2003-01-01

    It shows the variation in compressor mass flow with time as the mass flow is throttled to drive the compressor into surge. Surge begins where wide variations in mass flow occur. Air injection is then turned on to bring about a recovery from the initial surge condition and stabilize the compressor. The throttle is closed further until surge is again initiated. Air injection is increased to again recover from the surge condition and stabilize the compressor.

  15. Dosage-dependent non-linear effect of L-dopa on human motor cortex plasticity.

    Monte-Silva, Katia; Liebetanz, David; Grundey, Jessica; Paulus, Walter; Nitsche, Michael A

    2010-09-15

    The neuromodulator dopamine affects learning and memory formation and their likely physiological correlates, long-term depression and potentiation, in animals and humans. It is known from animal experiments that dopamine exerts a dosage-dependent, inverted U-shaped effect on these functions. However, this has not been explored in humans so far. In order to reveal a non-linear dose-dependent effect of dopamine on cortical plasticity in humans, we explored the impact of 25, 100 and 200 mg of L-dopa on transcranial direct current (tDCS)-induced plasticity in twelve healthy human subjects. The primary motor cortex served as a model system, and plasticity was monitored by motor evoked potential amplitudes elicited by transcranial magnetic stimulation. As compared to placebo medication, low and high dosages of L-dopa abolished facilitatory as well as inhibitory plasticity, whereas the medium dosage prolonged inhibitory plasticity, and turned facilitatory plasticity into inhibition. Thus the results show clear non-linear, dosage-dependent effects of dopamine on both facilitatory and inhibitory plasticity, and support the assumption of the importance of a specific dosage of dopamine optimally suited to improve plasticity. This might be important for the therapeutic application of dopaminergic agents, especially for rehabilitative purposes, and explain some opposing results in former studies.

  16. CEDM Controller for a Linear Pulse Motor by using Pulse Width Modulation Method in Integral Reactor

    Lee, Joon-Koo; Keum, Jong-Yong; Park, Heui-Youn

    2007-01-01

    Integral Reactor SMART is under development at KAERI. The design characteristics of SMART are radically different from those employed in currently operating loop type PWR in Korea. The reliability and accuracy of Control Rod Drive Mechanism are very important to the reactor safety and the design of the Plant Protection System. The SMART CEDM designed for fine-step movement consists of a linear pulse motor, reed switch type sensor with top and bottom limit switches which also act as Control Element Assembly(CEA) Position indicator, The linear pulse motor is a four phase synchronous DC electric machine with inner stator and output stator in coolant medium inside a strong housing. The objective of this paper is to introduce and to explain the CEDM controller CEDM Controller is being developed with a new design concept and digital technology to reduce the Operating Error and improve the systems' reliability and availability. And Switched Mode Power Supply is also being developed with digital hardware technology. This paper involves the test details and result

  17. Miniature Centrifugal Compressor

    Sixsmith, Herbert

    1989-01-01

    Miniature turbocompressor designed for reliability and long life. Cryogenic system includes compressor, turboexpander, and heat exchanger provides 5 W of refrigeration at 70 K from 150 W input power. Design speed of machine 510,000 rpm. Compressor has gas-lubricated journal bearings and magnetic thrust bearing. When compressor runs no bearing contact and no wear.

  18. Coatings for Fuel Cell Propulsion Compressor Bearings, Phase I

    National Aeronautics and Space Administration — Fuel cell air handling systems require clean and contaminant-free inlet air, which dictates that oil-free, motorized, compressor/expander systems should be used....

  19. Linear hypergeneralization of learned dynamics across movement speeds reveals anisotropic, gain-encoding primitives for motor adaptation.

    Joiner, Wilsaan M; Ajayi, Obafunso; Sing, Gary C; Smith, Maurice A

    2011-01-01

    The ability to generalize learned motor actions to new contexts is a key feature of the motor system. For example, the ability to ride a bicycle or swing a racket is often first developed at lower speeds and later applied to faster velocities. A number of previous studies have examined the generalization of motor adaptation across movement directions and found that the learned adaptation decays in a pattern consistent with the existence of motor primitives that display narrow Gaussian tuning. However, few studies have examined the generalization of motor adaptation across movement speeds. Following adaptation to linear velocity-dependent dynamics during point-to-point reaching arm movements at one speed, we tested the ability of subjects to transfer this adaptation to short-duration higher-speed movements aimed at the same target. We found near-perfect linear extrapolation of the trained adaptation with respect to both the magnitude and the time course of the velocity profiles associated with the high-speed movements: a 69% increase in movement speed corresponded to a 74% extrapolation of the trained adaptation. The close match between the increase in movement speed and the corresponding increase in adaptation beyond what was trained indicates linear hypergeneralization. Computational modeling shows that this pattern of linear hypergeneralization across movement speeds is not compatible with previous models of adaptation in which motor primitives display isotropic Gaussian tuning of motor output around their preferred velocities. Instead, we show that this generalization pattern indicates that the primitives involved in the adaptation to viscous dynamics display anisotropic tuning in velocity space and encode the gain between motor output and motion state rather than motor output itself.

  20. Transient analysis of a variable speed rotary compressor

    Park, Youn Cheol

    2010-01-01

    A transient simulation model of a rolling piston type rotary compressor is developed to predict the dynamic characteristics of a variable speed compressor. The model is based on the principles of conservation, real gas equations, kinematics of the crankshaft and roller, mass flow loss due to leakage, and heat transfer. For the computer simulation of the compressor, the experimental data were obtained from motor performance tests at various operating frequencies. Using the developed model, re-expansion loss, friction loss, mass flow loss and heat transfer loss is estimated as a function of the crankshaft speed in a variable speed compressor. In addition, the compressor efficiency and energy losses are predicted at various compressor-operating frequencies. Since the transient state of the compressor strongly depends on the system, the developed model is combined with a transient system simulation program to get transient variations of the compression process in the system. Motor efficiency, mechanical efficiency, motor torque and volumetric efficiency are calculated with respect to variation of the driving frequency in a rotary compressor.

  1. Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

    Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

    2017-01-01

    According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable. (paper)

  2. Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

    Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

    2017-07-01

    According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable.

  3. Rail Brake System Using a Linear Induction Motor for Dynamic Braking

    Sakamoto, Yasuaki; Kashiwagi, Takayuki; Tanaka, Minoru; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

    One type of braking system for railway vehicles is the eddy current brake. Because this type of brake has the problem of rail heating, it has not been used for practical applications in Japan. Therefore, we proposed the use of a linear induction motor (LIM) for dynamic braking in eddy current brake systems. The LIM reduces rail heating and uses an inverter for self excitation. In this paper, we estimated the performance of an LIM from experimental results of a fundamental test machine and confirmed that the LIM generates an approximately constant braking force under constant current excitation. At relatively low frequencies, this braking force remains unaffected by frequency changes. The reduction ratio of rail heating is also approximately proportional to the frequency. We also confirmed that dynamic braking resulting in no electrical output can be used for drive control of the LIM. These characteristics are convenient for the realization of the LIM rail brake system.

  4. Analysis and measure of novel stereo-garage driven by linear induction motor

    Lu Qinfen

    2015-12-01

    Full Text Available The car access time is a key parameter, especially in a huge stereo-garage, where this one should be decreased as much as possible. This paper proposes a novel stereo-garage. Adopting the linear induction motors (LIMs, the system has a simple structure and rapid response capability. In the stereo-garage, several LIMs are installed below the crossbeam on a lifting platform, and several LIMs are fixed on the top of a moving frame. During the operation of LIMs, the moving frame moves forward and backward to reach the required parking place, whereas the crossbeam moves horizontally in order to take or store the vehicle rapidly. All these LIMs are the same and should be designed at a low frequency. The influences of key structure parameters and dynamic performances are investigated, based on FEM. The predicted results are validated by a prototype. Finally, the designed LIMs are successfully applied in two 8-layer stereo-garages.

  5. Recession in a linear stepper motor based on piezoelectric actuator and electrorheological clampers

    Li, Cuihong; Meng, Yonggang; Tian, Yu

    2012-01-01

    A linear inchworm-type stepper motor based on piezoelectric actuator and comb shape electrorheological (ER) clampers was developed and tested. A recession phenomenon in the movement of the motor was found and was significantly affected by the driving voltage of the piezoelectric actuator and ER fluids. A dynamic model to analyze the mechanism of the recession was established. The force ratio of the viscoelastic clamping force (applied high electric field) to the viscous damping force (zero field) of ER fluids is the critical factor which determines the recession. The ratio is also affected by the extension or contraction rate of the actuator during movement, which is affected by the charging and discharging processes. With a relatively large distance between the clamper electrodes and a small displacement activated by the extension of the piezoelectric actuator, the instantaneous shear rate might not be sufficiently high, preventing ER fluids from attaining a shear-thickened and high-strength state. The ratio of yield strength to the viscous strength of ER fluids during movement should be as large as possible to reduce the recession displacement. (paper)

  6. A novel L-shaped linear ultrasonic motor operating in a single resonance mode

    Zhang, Bailiang; Yao, Zhiyuan; Liu, Zhen; Li, Xiaoniu

    2018-01-01

    In this study, a large thrust linear ultrasonic motor using an L-shaped stator is described. The stator is constructed by two mutually perpendicular rectangular plate vibrators, one of which is mounted in parallel with the slider to make the motor structure to be more compact. The symmetric and antisymmetric modes of the stator based on the first order bending vibration of two vibrators are adopted, in which each resonance mode is assigned to drive the slider in one direction. The placement of piezoelectric ceramics in a stator could be determined by finite element analysis, and the influence of slots in the head block on the vibration amplitudes of driving foot was studied as well. Three types of prototypes (non-slotted, dual-slot, and single-slot) were fabricated and experimentally investigated. Experimental results demonstrated that the prototype with one slot exhibited the best mechanical output performance. The maximum loads under the excitation of symmetric mode and antisymmetric mode were 65 and 90 N, respectively.

  7. A piezoelectric linear ultrasonic motor with the structure of a circular cylindrical stator and slider

    Sun, Dongming; Wang, Sheng; Sakurai, Junpei; Hata, Seiichi; Choi, Kee-Bong; Shimokohbe, Akira

    2010-01-01

    A piezoelectric linear ultrasonic motor is proposed, with a cylindrical stator and slider structure. The length and diameter of the motor are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe. The stator is designed based on theoretical analyses and finite element method (FEM) simulation. The traveling wave propagation is obtained in the FEM simulation under the proper geometrical sizes, suitable boundary conditions and driving voltage signals. The trajectories of particles on the TFMG pipe are elliptical motion. In the experiment, a 25 µm thick TFMG pipe is fabricated using the rotating magnetron sputtering technique and the vibration characteristics of the stator are measured by a laser Doppler vibrometer (LDV) system. Bidirectional motion of the slider is observed around 600 kHz, the maximum velocity is near to 40 mm s −1 at 50 Vp–p for the loose slider and the maximum output force is 6 mN at 70 Vp–p for the tight slider

  8. Development of linear pulse motor type control element drive mechanism for smart

    Je-Yong, Yu; Jong-in, Kim; Ji-ho, Kim; Hyung, Huh; Moon-Hee, Chang

    2001-01-01

    The system-integrated modular advanced reactor (SMART) currently under development at the Korea Atomic Energy Research Institute is being designed with soluble boron free operation and the use of nuclear heating for reactor start-up. These design features require a Control Element Drive Mechanism(CEDM) for SMART to have fine-step movement capability as well as high reliability for fine reactivity control. In this paper, the design characteristics of a new concept CEDM driven by a Linear Pulse Motor (LPM) which meets the design requirements of the integral reactor SMART are introduced. The primary dimensions of the linear pulse motor are determined by electro-magnetic analysis and the results are also presented. In parallel with the electro-magnetic analysis, the conceptual design of the CEDM is visualized and checked for interferences among parts by assembling three dimensional (3D) models on computer. A prototype of the LPM with double air-gaps for the CEDM sub-assemblies to lift 100 kg is designed, analysed, manufactured and tested to confirm the validity of the CEDM design concept. A converter and test facility are manufactured to verify the dynamic performance of the LPM. The mover of the LPM is welded with ferromagnetic material and non-ferromagnetic material to get the magnetic flux path between the inner stator and outer stator. The thrust forces of LPM predicted by the analytic model have shown good agreement with experimental results from the prototype LPM. It is found that the LPM type CEDM has high force density and a simple drive mechanism to reduce volume and satisfy reactor operating circumstances with high pressure and temperature. (authors)

  9. Linear pulse motor type control element drive mechanism for the integral reactor

    Yu, J. Y.; Choi, S.; Kim, J. H.; Huh, H.; Park, K. B.

    2007-01-01

    The integral reactor SMART currently under development at Korea Atomic Energy Research Institute is designed with soluble boron free operation and use of nuclear heating for reactor startup. These design features require the Control Element Drive Mechanism (CEDM) for SMART to have fine-step movement capability as well as high reliability for the fine reactivity control. In this paper, design characteristics of a new concept CEDM driven by the Linear Pulse Motor (LPM) which meets the design requirements of the integral reactor SMART are introduced. The primary dimensions of the linear pulse motor are determined by the electro-magnetic analysis and the results are also presented. In parallel with the electro-magnetic analysis, the conceptual design of the CEDM is visualized and checked for interferences among parts by assembling three dimensional (3D) models on the computer. Prototype of LPM with double air-gaps for the CEDM sub-assemblies to lift 100 kg is designed, analysed, manufactured and tested to confirm the validity of the CEDM design concept. A converter and a test facility are manufactured to verify the dynamic performance of the LPM. The mover of the LPM is welded with ferromagnetic material and non-ferromagnetic material to get the magnetic flux path between inner stator and outer stator. The thrust forces of LPM predicted by analytic model have shown good agreement with experimental results from the prototype LPM. It is found that the LPM type CEDM has high force density and simple drive mechanism to reduce volume and satisfy the reactor operating circumstances with high pressure and temperature

  10. Novel Synchronous Linear and Rotatory Micro Motors Based on Polymer Magnets with Organic and Inorganic Insulation Layers

    Andreas WALDSCHIK

    2008-12-01

    Full Text Available In this work, we report on the development of several synchronous motors with rotatory or linear movements. The synchronous micro motors are brushless DC motors or stepper motors with electrically controlled commutation consisting of a stator and a rotor. The rotor is mounted onto the stator and is adjusted by an integrated guidance. Inside the stator different coil systems are realized, like double layer sector coils or special nested coils. The coil systems can be controlled by three or six phases depending on the operational mode. Furthermore, inorganic insulation layers were used in order to reduce the thickness of the system. By this means four layers of electrical conductors can be realized especially for the 2D devices. The smallest diameter of the rotatory motor is 1 mm and could be successfully driven.

  11. Design of decoupled dual servo stage with voice coil motor and linear motor for XY long stroke ultra-precision scanning system

    Kim, Ki-Hyun; Choi, Young-Man; Gweon, Dae-Gab; Hong, Dong-Pyo; Kim, Koung-Suk; Lee, Suk-Won; Lee, Moon-Gu

    2005-12-01

    A decoupled dual servo (DDS) stage for ultra-precision scanning system is introduced in this paper. The proposed DDS consists of a 3 axis fine stage for handling and carrying workpieces and a XY coarse stage. Especially, the DDS uses three voice coil motors (VCM) as a planar actuation system of the fine stage to reduce the disturbances due to any mechanical connections with its coarse stage. VCMs are governed by Lorentz law. According to the law and its structure, there are no mechanical connections between coils and magnetic circuits. Moreover, the VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about 5mm2. To break that hurdle, the coarse stage with linear motors is used for the fine stage to move about 200mm2. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. Using MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. For linear motors, Halbach magnet linear motor is proposed and optimally designed in this paper. In addition, for their smooth movements without any frictions, guide systems of the DDS are composed of air bearings. And then, precisely to get their positions, linear scales with 0.1um resolution are used for the coarse's XY motions and plane mirror laser interferometers with 20nm for the fine's XYθz. On scanning, the two stages have same trajectories and are controlled. The control algorithm is Parallel method. The embodied ultra-precision scanning system has about 100nm tracking error and in-positioning stability.

  12. Mathematical Model and Computational Analysis of Selected Transient States of Cylindrical Linear Induction Motor Fed via Frequency Converter

    Andrzej Rusek

    2008-01-01

    Full Text Available The mathematical model of cylindrical linear induction motor (C-LIM fed via frequency converter is presented in the paper. The model was developed in order to analyze numerically the transient states. Problems concerning dynamics of ac-machines especially linear induction motor are presented in [1 – 7]. Development of C-LIM mathematical model is based on circuit method and analogy to rotary induction motor. The analogy between both: (a stator and rotor windings of rotary induction motor and (b winding of primary part of C-LIM (inductor and closed current circuits in external secondary part of C-LIM (race is taken into consideration. The equations of C-LIM mathematical model are presented as matrix together with equations expressing each vector separately. A computational analysis of selected transient states of C-LIM fed via frequency converter is presented in the paper. Two typical examples of C-LIM operation are considered for the analysis: (a starting the motor at various static loads and various synchronous velocities and (b reverse of the motor at the same operation conditions. Results of simulation are presented as transient responses including transient electromagnetic force, transient linear velocity and transient phase current.

  13. Flux modeling and analysis of a linear induction motor for steel mill non-contacting conveyance system application

    Liu, C.-T.; Lin, S.-Y.; Yang, Y.-Y.

    2005-01-01

    A detailed mathematical approach for analyzing static/dynamic characteristics of a linear induction motor for steel mill non-contacting conveyance system application will be provided. The dependent reluctances among the motor secondary steel plate and primary poles have been systematically formulated; hence, the operational performance of the system can be derived conveniently. Results showed that not only the motor structure is suitable for the design objective, but also the proposed magnetic equivalent circuit can provide appropriate and convenient modeling for relative analytical investigations

  14. Application of the Hyper-Poisson Generalized Linear Model for Analyzing Motor Vehicle Crashes.

    Khazraee, S Hadi; Sáez-Castillo, Antonio Jose; Geedipally, Srinivas Reddy; Lord, Dominique

    2015-05-01

    The hyper-Poisson distribution can handle both over- and underdispersion, and its generalized linear model formulation allows the dispersion of the distribution to be observation-specific and dependent on model covariates. This study's objective is to examine the potential applicability of a newly proposed generalized linear model framework for the hyper-Poisson distribution in analyzing motor vehicle crash count data. The hyper-Poisson generalized linear model was first fitted to intersection crash data from Toronto, characterized by overdispersion, and then to crash data from railway-highway crossings in Korea, characterized by underdispersion. The results of this study are promising. When fitted to the Toronto data set, the goodness-of-fit measures indicated that the hyper-Poisson model with a variable dispersion parameter provided a statistical fit as good as the traditional negative binomial model. The hyper-Poisson model was also successful in handling the underdispersed data from Korea; the model performed as well as the gamma probability model and the Conway-Maxwell-Poisson model previously developed for the same data set. The advantages of the hyper-Poisson model studied in this article are noteworthy. Unlike the negative binomial model, which has difficulties in handling underdispersed data, the hyper-Poisson model can handle both over- and underdispersed crash data. Although not a major issue for the Conway-Maxwell-Poisson model, the effect of each variable on the expected mean of crashes is easily interpretable in the case of this new model. © 2014 Society for Risk Analysis.

  15. Compressors selection and sizing

    Brown, Royce N

    2005-01-01

    This practical reference provides in-depth information required to understand and properly estimate compressor capabilities and to select the proper designs. Engineers and students will gain a thorough understanding of compression principles, equipment, applications, selection, sizing, installation, and maintenance. The many examples clearly illustrate key aspects to help readers understand the ""real world"" of compressor technology.Compressors: Selection and Sizing, third edition is completely updated with new API standards. Additions requested by readers include a new section on di

  16. The Compressor Recycle System

    Barstad, Bjørn Ove

    2010-01-01

    The compressor recycle system is the main focus of this thesis. When the mass flow through a compressor becomes too low, the compressor can plunge into surge. Surge is a term that is used for axisymmetric oscillation through a compressor and is highly unwanted. The recycle system feeds compressed gas back to the intake when the mass flow becomes too low, and thereby act as a safety system.A mathematical model of the recycle system is extended and simulated in SIMULINK. The mathematical model ...

  17. Linear methods for reducing EMG contamination in peripheral nerve motor decodes.

    Kagan, Zachary B; Wendelken, Suzanne; Page, David M; Davis, Tyler; Hutchinson, Douglas T; Clark, Gregory A; Warren, David J

    2016-08-01

    Signals recorded from the peripheral nervous system (PNS) with high channel count penetrating microelectrode arrays, such as the Utah Slanted Electrode Array (USEA), often have electromyographic (EMG) signals contaminating the neural signal. This common-mode signal source may prevent single neural units from successfully being detected, thus hindering motor decode algorithms. Reducing this EMG contamination may lead to more accurate motor decode performance. A virtual reference (VR), created by a weighted linear combination of signals from a subset of all available channels, can be used to reduce this EMG contamination. Four methods of determining individual channel weights and six different methods of selecting subsets of channels were investigated (24 different VR types in total). The methods of determining individual channel weights were equal weighting, regression-based weighting, and two different proximity-based weightings. The subsets of channels were selected by a radius-based criteria, such that a channel was included if it was within a particular radius of inclusion from the target channel. These six radii of inclusion were 1.5, 2.9, 3.2, 5, 8.4, and 12.8 electrode-distances; the 12.8 electrode radius includes all USEA electrodes. We found that application of a VR improves the detectability of neural events via increasing the SNR, but we found no statistically meaningful difference amongst the VR types we examined. The computational complexity of implementation varies with respect to the method of determining channel weights and the number of channels in a subset, but does not correlate with VR performance. Hence, we examined the computational costs of calculating and applying the VR and based on these criteria, we recommend an equal weighting method of assigning weights with a 3.2 electrode-distance radius of inclusion. Further, we found empirically that application of the recommended VR will require less than 1 ms for 33.3 ms of data from one USEA.

  18. Modeling and experimental analysis of the linear ultrasonic motor with in-plane bending and longitudinal mode.

    Wan, Zhijian; Hu, Hong

    2014-03-01

    A novel linear ultrasonic motor based on in-plane longitudinal and bending mode vibration is presented in this paper. The stator of the motor is composed of a metal plate and eight piezoelectric ceramic patches. There are four long holes in the plate, designed for consideration of the longitudinal and bending mode coupling. The corresponding model is developed to optimize the mechanical and electrical coupling of the stator, which causes an ellipse motion at the contact tip of the stator when the composite vibrations with longitudinal and bending are excited. Its harmonic and transient responses are simulated and inspected. A prototype based on the model is fabricated and used to conduct experiments. Results show that the amplitude of the stator's contact tips is significantly increased, which helps to amplify the driving force and speed of the motor. It is therefore feasible to implement effective linear movement using the developed prototype. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Design and characterization of a microelectromechanical system electro-thermal linear motor with interlock mechanism for micro manipulators.

    Hu, Tengjiang; Zhao, Yulong; Li, Xiuyuan; Zhao, You; Bai, Yingwei

    2016-03-01

    The design, fabrication, and testing of a novel electro-thermal linear motor for micro manipulators is presented in this paper. The V-shape electro-thermal actuator arrays, micro lever, micro spring, and slider are introduced. In moving operation, the linear motor can move nearly 1 mm displacement with 100 μm each step while keeping the applied voltage as low as 17 V. In holding operation, the motor can stay in one particular position without consuming energy and no creep deformation is found. Actuation force of 12.7 mN indicates the high force generation capability of the device. Experiments of lifetime show that the device can wear over two million cycles of operation. A silicon-on-insulator wafer is introduced to fabricate a high aspect ratio structure and the chip size is 8.5 mm × 8.5 mm × 0.5 mm.

  20. A square-plate piezoelectric linear motor operating in two orthogonal and isomorphic face-diagonal-bending modes.

    Ci, Penghong; Chen, Zhijiang; Liu, Guoxi; Dong, Shuxiang

    2014-01-01

    We report a piezoelectric linear motor made of a single Pb(Zr,Ti)O3 square-plate, which operates in two orthogonal and isomorphic face-diagonal-bending modes to produce precision linear motion. A 15 × 15 × 2 mm prototype was fabricated, and the motor generated a driving force of up to 1.8 N and a speed of 170 mm/s under an applied voltage of 100 Vpp at the resonance frequency of 136.5 kHz. The motor shows such advantages as large driving force under relatively low driving voltage, simple structure, and stable motion because of its isomorphic face-diagonal-bending mode.

  1. Analysis and testing of a double armature brushless dc linear motor with NdFeB permanent magnets

    Filho, A.F.F.

    1998-01-01

    The use of high-energy product NdFeB permanent magnets benefits the design and features of a double armature brushless dc linear motor. As the linear motor is also slotless, its 5 mm airgap requires a source of high flux to overcome the reluctance and produce an adequate amount of force. The linear motor employs a topology that makes use of five permanent magnets to provide excitation flux. The permanent magnets are arranged in such a way that maximises the force the linear motor can deliver. The actuator produces a force up to 86.2 N at an armature current of 4.5 A. However, the topology makes the actuator prone to saturation. It affects the operation point of the permanent magnets, reduces the airgap flux density and the force, and increases flux leakage. To avoid saturation, a flux compensation scheme was conceived. The results are presented and assessed by means of finite element simulation and by experimental results that presented a good agreement. (orig.)

  2. High ratio recirculating gas compressor

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  3. Motor Behavior: From Telegraph Keys and Twins to Linear Slides and Stepping

    Thomas, Jerry R.

    2006-01-01

    Motor behavior is a significant area of scholarship with 64 Fellows from the American Academy of Kinesiology and Physical Education engaged in that work since 1930. This paper provides a brief overview of the history of research in motor development and motor control/learning, particularly noting the contributions to scholarship of Academy…

  4. Sorption compressor/mechanical expander hybrid refrigeration

    Jones, J. A.; Britcliffe, M.

    1987-01-01

    Experience with Deep Space Network (DSN) ground-based cryogenic refrigerators has proved the reliability of the basic two-stage Gifford-McMahon helium refrigerator. A very long life cryogenic refrigeration system appears possible by combining this expansion system or a turbo expansion system with a hydride sorption compressor in place of the usual motor driven piston compressor. To test the feasibility of this system, a commercial Gifford-McMahon refrigerator was tested using hydrogen gas as the working fluid. Although no attempt was made to optimize the system for hydrogen operation, the refrigerator developed 1.3 W at 30 K and 6.6 W at 60 K. The results of the test and of theoretical performances of the hybrid compressor coupled to these expansion systems are presented.

  5. Optimized linear motor and digital PID controller setup used in Mössbauer spectrometer

    Kohout, Pavel; Kouřil, Lukáš; Navařík, Jakub; Novák, Petr; Pechoušek, Jiří

    2014-10-01

    Optimization of a linear motor and digital PID controller setup used in a Mössbauer spectrometer is presented. Velocity driving system with a digital PID feedback subsystem was developed in the LabVIEW graphical environment and deployed on the sbRIO real-time hardware device (National Instruments). The most important data acquisition processes are performed as real-time deterministic tasks on an FPGA chip. Velocity transducer of a double loudspeaker type with a power amplifier circuit is driven by the system. Series of calibration measurements were proceeded to find the optimal setup of the P, I, D parameters together with velocity error signal analysis. The shape and given signal characteristics of the velocity error signal are analyzed in details. Remote applications for controlling and monitoring the PID system from computer or smart phone, respectively, were also developed. The best setup and P, I, D parameters were set and calibration spectrum of α-Fe sample with an average nonlinearity of the velocity scale below 0.08% was collected. Furthermore, the width of the spectral line below 0.30 mm/s was observed. Powerful and complex velocity driving system was designed.

  6. Displacement compressors - acceptance tests

    International Organization for Standardization. Geneva

    1996-01-01

    ISO 1217:2009 specifies methods for acceptance tests regarding volume rate of flow and power requirements of displacement compressors. It also specifies methods for testing liquid-ring type compressors and the operating and testing conditions which apply when a full performance test is specified.

  7. A study of thermal deformation in the carriage of a permanent magnet direct drive linear motor stage

    Chow, J.H.; Zhong, Z.W.; Lin, W.; Khoo, L.P.

    2012-01-01

    Carriage deformation due to temperature gradients within the materials of the carriage affects the accuracy of precision machines. This is largely due to the indeterminist temperature distribution in the carriage's material caused by the non-linearity of heat transfer. The joule heat from the motor coil forms the main heat source. When coupled with the heat loss through convection and radiation, the temperature variation in the motor's carriage also increases. In this study, the Finite Element Analysis was used together with a set of boundary conditions, which was obtained empirically, to analyze the distortion of the motor's carriage. The simulated results were compared with those obtained through experiments. The study shows that it is important to know, rather than to assume, the thermal boundary conditions of the motor's carriage of a precision machine in order to accurately estimate the thermal deformation of the carriage in precision machining. - Highlights: ► Deformation occurs in carriages which are mounted with linear motor. ► The convective coefficient, which is assumed to be 10 W mm −2 , is shown to be invalid. ► The perfect contact conductance is shown to be invalid too. ► To have an accurate thermal model, boundary conditions have to be realistic. ► Boundary conditions are the heat source, convective and conductance values.

  8. Orbiting compressor for residential air-conditioners

    Kim, Hyun Jin; Kim, Woo Young; Ahn, Jong Min [Department of Mechanical Engineering, University of Incheon, 12-1 Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea)

    2010-01-15

    A new type of compressor, called an orbiting compressor, is introduced in this paper. The orbiting compressor is characterized by an orbiting piston, and the piston or orbiter consists of a circular base plate and a ring type vane protruding vertically from the base plate. The orbiter is made to orbit in an annular space formed between two concentric circular walls via an Oldham-ring mechanism, producing two sealed gas pockets on both sides of the vane wrap with a 180 phase difference. This operating mechanism leads to alternating compression and discharge processes, which results in low torque variation. The orbiting compressor has been designed for an R410A residential air conditioner with a cooling capacity of 10.0 kW. The performance of the orbiting compressor model has been analytically investigated, where the volumetric, adiabatic and mechanical efficiencies were calculated to be 94.8%, 90.4% and 93.4%, respectively for the ARI condition. The EER was estimated to be about 10.86 with a motor efficiency of 89%. (author)

  9. Analysis and Design of a Maglev Permanent Magnet Synchronous Linear Motor to Reduce Additional Torque in dq Current Control

    Feng Xing

    2018-03-01

    Full Text Available The maglev linear motor has three degrees of motion freedom, which are respectively realized by the thrust force in the x-axis, the levitation force in the z-axis and the torque around the y-axis. Both the thrust force and levitation force can be seen as the sum of the forces on the three windings. The resultant thrust force and resultant levitation force are independently controlled by d-axis current and q-axis current respectively. Thus, the commonly used dq transformation control strategy is suitable for realizing the control of the resultant force, either thrust force and levitation force. However, the forces on the three windings also generate additional torque because they do not pass the mover mass center. To realize the maglev system high-precision control, a maglev linear motor with a new structure is proposed in this paper to decrease this torque. First, the electromagnetic model of the motor can be deduced through the Lorenz force formula. Second, the analytic method and finite element method are used to explore the reason of this additional torque and what factors affect its change trend. Furthermore, a maglev linear motor with a new structure is proposed, with two sets of 90 degrees shifted winding designed on the mover. Under such a structure, the mover position dependent periodic part of the additional torque can be offset. Finally, the theoretical analysis is validated by the simulation result that the additionally generated rotating torque can be offset with little fluctuation in the proposed new-structure maglev linear motor. Moreover, the control system is built in MATLAB/Simulink, which shows that it has small thrust ripple and high-precision performance.

  10. The development and testing of a linear induction motor being fed from the source with limited electric power

    Tiunov, V. V.

    2018-02-01

    The report provides results of the research related to the tubular linear induction motors’ application. The motors’ design features, a calculation model, a description of test specimens for mining and electric power industry are introduced. The most attention is given to the single-phase motors for high voltage switches drives with the usage of inexpensive standard single-phase transformers for motors’ power supply. The method of the motor’s parameters determination, when the motor is being fed from the transformer, working in the overload mode, was described, and the results of it practical usage were good enough for the engineering practice.

  11. EEG sensorimotor rhythms' variation and functional connectivity measures during motor imagery: linear relations and classification approaches.

    Stefano Filho, Carlos A; Attux, Romis; Castellano, Gabriela

    2017-01-01

    Hands motor imagery (MI) has been reported to alter synchronization patterns amongst neurons, yielding variations in the mu and beta bands' power spectral density (PSD) of the electroencephalography (EEG) signal. These alterations have been used in the field of brain-computer interfaces (BCI), in an attempt to assign distinct MI tasks to commands of such a system. Recent studies have highlighted that information may be missing if knowledge about brain functional connectivity is not considered. In this work, we modeled the brain as a graph in which each EEG electrode represents a node. Our goal was to understand if there exists any linear correlation between variations in the synchronization patterns-that is, variations in the PSD of mu and beta bands-induced by MI and alterations in the corresponding functional networks. Moreover, we (1) explored the feasibility of using functional connectivity parameters as features for a classifier in the context of an MI-BCI; (2) investigated three different types of feature selection (FS) techniques; and (3) compared our approach to a more traditional method using the signal PSD as classifier inputs. Ten healthy subjects participated in this study. We observed significant correlations ( p  < 0.05) with values ranging from 0.4 to 0.9 between PSD variations and functional network alterations for some electrodes, prominently in the beta band. The PSD method performed better for data classification, with mean accuracies of (90 ± 8)% and (87 ± 7)% for the mu and beta band, respectively, versus (83 ± 8)% and (83 ± 7)% for the same bands for the graph method. Moreover, the number of features for the graph method was considerably larger. However, results for both methods were relatively close, and even overlapped when the uncertainties of the accuracy rates were considered. Further investigation regarding a careful exploration of other graph metrics may provide better alternatives.

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

    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.

  13. An analytical method for the calculation of static characteristics of linear step motors for control rod drives in nuclear reactors

    Khan, S.H.; Ivanov, A.A.

    1995-01-01

    An analytical method for calculating static characteristics of linear dc step motors (LSM) is described. These multiphase passive-armature motors are now being developed for control rod drives (CRD) in large nuclear reactors. The static characteristics of such LSM is defined by the variation of electromagnetic force with armature displacement and it determines motor performance in its standing and dynamic modes of operation. The proposed analytical technique for calculating this characteristic is based on the permeance analysis method applied to phase magnetic circuits of LSM. Reluctances of various parts of phase magnetic circuit is calculated analytically by assuming probable flux paths and by taking into account complex nature of magnetic field distribution in it. For given armature positions stator and armature iron saturations are taken into account by an efficient iterative algorithm which gives fast convergence. The method is validated by comparing theoretical results with experimental ones which shows satisfactory agreement for small stator currents and weak iron saturation

  14. Development of Propulsion Inverter Control System for High-Speed Maglev based on Long Stator Linear Synchronous Motor

    Jeong-Min Jo

    2017-02-01

    Full Text Available In the case of a long-stator linear drive, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signals transmitted from a maglev vehicle cannot meet the need of the real-time propulsion control in the on-ground inverter power substations. In this paper the design of the propulsion inverter control system with a position estimator for driving a long-stator synchronous motor in a high-speed maglev train is proposed. The experiments have been carried out at the 150 m long guideway at the O-song test track. To investigate the performance of the position estimator, the propulsion control system with, and without, the position estimator are compared. The result confirms that the proposed strategy can meet the dynamic property needs of the propulsion inverter control system for driving long-stator linear synchronous motors.

  15. Simplified 3D Finite Element Analysis of Linear Inductor Motor for Integrated Magnetic Suspension/Propulsion Applications

    Jeong, Sang Sub; Jang Seok Myeong [Chungnam National University(Korea)

    2000-06-01

    The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed mode., we compare with the results of simplified 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis. (author). refs., figs., tabs.

  16. Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

    Lee, Dong-Jin; Lee, Sun-Kyu

    2015-01-01

    This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

  17. H-Shaped Multiple Linear Motor Drive Platform Control System Design Based on an Inverse System Method

    Caiyan Qin

    2017-12-01

    Full Text Available Due to its simple mechanical structure and high motion stability, the H-shaped platform has been increasingly widely used in precision measuring, numerical control machining and semiconductor packaging equipment, etc. The H-shaped platform is normally driven by multiple (three permanent magnet synchronous linear motors. The main challenges for H-shaped platform-control include synchronous control between the two linear motors in the Y direction as well as total positioning error of the platform mover, a combination of position deviation in X and Y directions. To deal with the above challenges, this paper proposes a control strategy based on the inverse system method through state feedback and dynamic decoupling of the thrust force. First, mechanical dynamics equations have been deduced through the analysis of system coupling based on the platform structure. Second, the mathematical model of the linear motors and the relevant coordinate transformation between dq-axis currents and ABC-phase currents are analyzed. Third, after the main concept of inverse system method being explained, the inverse system model of the platform control system has been designed after defining relevant system variables. Inverse system model compensates the original nonlinear coupled system into pseudo-linear decoupled linear system, for which typical linear control methods, like PID, can be adopted to control the system. The simulation model of the control system is built in MATLAB/Simulink and the simulation result shows that the designed control system has both small synchronous deviation and small total trajectory tracking error. Furthermore, the control program has been run on NI controller for both fixed-loop-time and free-loop-time modes, and the test result shows that the average loop computation time needed is rather small, which makes it suitable for real industrial applications. Overall, it proves that the proposed new control strategy can be used in

  18. Vibration Analysis and Experimental Research of the Linear-Motor-Driven Water Piston Pump Used in the Naval Ship

    Ye-qing Huang

    2016-01-01

    Full Text Available Aiming at the existing problems of traditional water piston pump used in the naval ship, such as low efficiency, high noise, large vibration, and nonintelligent control, a new type of linear-motor-driven water piston pump is developed and its vibration characteristics are analyzed in this research. Based on the 3D model of the structure, the simulation analyses including static stress analysis, modal analysis, and harmonic response analysis are conducted. The simulation results reveal that the mode shape under low frequency stage is mainly associated with the eccentricity swing of the piston rod. The vibration experiment results show that the resonance frequency of linear-motor-driven water piston pump is concentrated upon 500 Hz and 800 Hz in the low frequency range. The dampers can change the resonance frequency of the system to a certain extent. The vibration under triangular motion curve is much better than that of S curve, which is consistent with the simulation conclusion. This research provides an effective method to detect the vibration characteristics and a reference for design and optimization of the linear-motor-driven water piston pump.

  19. Intelligent measurement and compensation of linear motor force ripple: a projection-based learning approach in the presence of noise

    Liu, Yang; Song, Fazhi; Yang, Xiaofeng; Dong, Yue; Tan, Jiubin

    2018-06-01

    Due to their structural simplicity, linear motors are increasingly receiving attention for use in high velocity and high precision applications. The force ripple, as a space-periodic disturbance, however, would deteriorate the achievable dynamic performance. Conventional force ripple measurement approaches are time-consuming and have high requirements on the experimental conditions. In this paper, a novel learning identification algorithm is proposed for force ripple intelligent measurement and compensation. Existing identification schemes always use all the error signals to update the parameters in the force ripple. However, the error induced by noise is non-effective for force ripple identification, and even deteriorates the identification process. In this paper only the most pertinent information in the error signal is utilized for force ripple identification. Firstly, the effective error signals caused by the reference trajectory and the force ripple are extracted by projecting the overall error signals onto a subspace spanned by the physical model of the linear motor as well as the sinusoidal model of the force ripple. The time delay in the linear motor is compensated in the basis functions. Then, a data-driven approach is proposed to design the learning gain. It balances the trade-off between convergence speed and robustness against noise. Simulation and experimental results validate the proposed method and confirm its effectiveness and superiority.

  20. Inhibition linearizes firing rate responses in human motor units: implications for the role of persistent inward currents.

    Revill, Ann L; Fuglevand, Andrew J

    2017-01-01

    Motor neurons are the output neurons of the central nervous system and are responsible for controlling muscle contraction. When initially activated during voluntary contraction, firing rates of motor neurons increase steeply but then level out at modest rates. Activation of an intrinsic source of excitatory current at recruitment onset may underlie the initial steep increase in firing rate in motor neurons. We attempted to disable this intrinsic excitatory current by artificially activating an inhibitory reflex. When motor neuron activity was recorded while the inhibitory reflex was engaged, firing rates no longer increased steeply, suggesting that the intrinsic excitatory current was probably responsible for the initial sharp rise in motor neuron firing rate. During graded isometric contractions, motor unit (MU) firing rates increase steeply upon recruitment but then level off at modest rates even though muscle force continues to increase. The mechanisms underlying such firing behaviour are not known although activation of persistent inward currents (PICs) might be involved. PICs are intrinsic, voltage-dependent currents that activate strongly when motor neurons (MNs) are first recruited. Such activation might cause a sharp escalation in depolarizing current and underlie the steep initial rise in MU firing rate. Because PICs can be disabled with synaptic inhibition, we hypothesized that artificial activation of an inhibitory pathway might curb this initial steep rise in firing rate. To test this, human subjects performed slow triangular ramp contractions of the ankle dorsiflexors in the absence and presence of tonic synaptic inhibition delivered to tibialis anterior (TA) MNs by sural nerve stimulation. Firing rate profiles (expressed as a function of contraction force) of TA MUs recorded during these tasks were compared for control and stimulation conditions. Under control conditions, during the ascending phase of the triangular contractions, 93% of the firing

  1. Cooled spool piston compressor

    Morris, Brian G. (Inventor)

    1993-01-01

    A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

  2. Leak-tight compressor

    Bogomolova, L.K.; Vasilenko, A.T.

    1974-01-01

    The publication describes the construction and operating principle of the sealed uniflow compressor. This compressor insures against substantial contamination of the medium handled. Use of the slot-type sealing of the piston and rejection of the sliding bearings result in insuring high purity of the medium handled. The compressor performance is as follows: maximum air throughput - 262.6 1/h at 24 deg C and absolute outlet pressure being 1.14 kgf/cm 2 , minimum air throughput - 82.6 1/h at 24 deg C and absolute outlet pressure being 1.4 kgf/cm 2 ; inlet pressure equals 1 kgf/cm 2 . The compressor is provided with a solenoid-operated drive. The prototype has been in service for 6 months, with accumulated service time amounting to 500 h. The compressor has given a good account of itself within this period. The compressor is to be used in the gas purification circuit when this gas is used as a working medium in the spark or streamer chambers

  3. Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping.

    Schumacher, Christian; Seyfarth, André

    2017-01-01

    In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB), velocity (VFB) and force feedback (FFB) pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort). Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map . The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency). Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length) or environmental parameters (ground compliance). Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a specific

  4. A novel large thrust-weight ratio V-shaped linear ultrasonic motor with a flexible joint.

    Li, Xiaoniu; Yao, Zhiyuan; Yang, Mojian

    2017-06-01

    A novel large thrust-weight ratio V-shaped linear ultrasonic motor with a flexible joint is proposed in this paper. The motor is comprised of a V-shaped transducer, a slider, a clamp, and a base. The V-shaped transducer consists of two piezoelectric beams connected through a flexible joint to form an appropriate coupling angle. The V-shaped motor is operated in the coupled longitudinal-bending mode. Longitudinal and bending movements are transferred by the flexible joint between the two beams. Compared with the coupled longitudinal-bending mode of the single piezoelectric beam or the symmetrical and asymmetrical modes of the previous V-shaped transducer, the coupled longitudinal-bending mode of the V-shaped transducer with a flexible joint provides higher vibration efficiency and more convenient mode conformance adjustment. A finite element model of the V-shaped transducer is created to numerically study the influence of geometrical parameters and to determine the final geometrical parameters. In this paper, three prototypes were then fabricated and experimentally investigated. The modal test results match well with the finite element analysis. The motor mechanical output characteristics of three different coupling angles θ indicate that V-90 (θ = 90°) is the optimal angle. The mechanical output experiments conducted using the V-90 prototype (Size: 59.4 mm × 30.7 mm × 4 mm) demonstrate that the maximum unloaded speed is 1.2 m/s under a voltage of 350 Vpp, and the maximum output force is 15 N under a voltage of 300 Vpp. The proposed novel V-shaped linear ultrasonic motor has a compact size and a simple structure with a large thrust-weight ratio (0.75 N/g) and high speed.

  5. Design of a Control System for a Maglev Planar Motor Based on Two-Dimension Linear Interpolation

    Feng Xing

    2017-08-01

    Full Text Available In order to realize the high speed and high-precision control of a maglev planar motor, a high-precision electromagnetic model is needed in the first place, which can also contribute to meeting the real-time running requirements. Traditionally, the electromagnetic model is based on analytical calculations. However, this neglects the model simplification and the manufacturing errors, which may bring certain errors to the model. Aiming to handle this inaccuracy, this paper proposes a novel design method for a maglev planar motor control system based on two-dimensional linear interpolation. First, the magnetic field is divided into several regions according to the symmetry of the Halbach magnetic array, and the uniform grid method is adopted to partition one of these regions. Second, targeting this region, it is possible to sample the electromagnetic forces and torques on each node of the grid and obtain the complete electromagnetic model in this region through the two-dimensional linear interpolation method. Third, the whole electromagnetic model of the maglev planar motor can be derived according to the symmetry of the magnetic field. Finally, the decoupling method and controller are designed according to this electromagnetic model, and thereafter, the control model can be established. The designed control system is demonstrated through simulations and experiments to feature better accuracy and meet the requirements of real-time control.

  6. Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping

    Christian Schumacher

    2017-11-01

    Full Text Available In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB, velocity (VFB and force feedback (FFB pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort. Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map. The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency. Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length or environmental parameters (ground compliance. Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a

  7. Linear versus non-linear measures of temporal variability in finger tapping and their relation to performance on open- versus closed-loop motor tasks: comparing standard deviations to Lyapunov exponents.

    Christman, Stephen D; Weaver, Ryan

    2008-05-01

    The nature of temporal variability during speeded finger tapping was examined using linear (standard deviation) and non-linear (Lyapunov exponent) measures. Experiment 1 found that right hand tapping was characterised by lower amounts of both linear and non-linear measures of variability than left hand tapping, and that linear and non-linear measures of variability were often negatively correlated with one another. Experiment 2 found that increased non-linear variability was associated with relatively enhanced performance on a closed-loop motor task (mirror tracing) and relatively impaired performance on an open-loop motor task (pointing in a dark room), especially for left hand performance. The potential uses and significance of measures of non-linear variability are discussed.

  8. Calculation of static characteristics of linear step motors for control rod drives of nuclear reactors - an approximate approach

    Khan, S.H.; Ivanov, A.A.

    1993-01-01

    This paper describes an approximate method for calculating the static characteristics of linear step motors (LSM), being developed for control rod drives (CRD) in large nuclear reactors. The static characteristic of such an LSM which is given by the variation of electromagnetic force with armature displacement determines the motor performance in its standing and dynamic modes. The approximate method of calculation of these characteristics is based on the permeance analysis method applied to the phase magnetic circuit of LSM. This is a simple, fast and efficient analytical approach which gives satisfactory results for small stator currents and weak iron saturation, typical to the standing mode of operation of LSM. The method is validated by comparing theoretical results with experimental ones. (Author)

  9. MODELING OF OPERATION OF COAXIAL-LINEAR MOTORS WITH AXIAL AND RADIAL DIRECTIONS OF MAGNETIZATION OF PERMANENT MAGNETS IN DYNAMIC MODE

    G.M. Golenkov

    2014-12-01

    Full Text Available Theoretical and experimental investigations of the amplitude, phase and inertia-power frequency characteristics of two types of coaxial-linear electric motors of back-and-forth motion with permanent magnets, which magnetization vector is directed axially and radially relative to the axis of the runner are carried out. The comparative analysis of characteristics of these motors is presented.

  10. Non Linear, Time Variant Speed Control of a Single Phase Hybrid Switched Reluctance Motor

    Jakobsen, Uffe; Ahn, Jin Woo

    2009-01-01

    A high torque ripple in a given motor always presents a challenge for the speed control, since this ripple may lead to excessive actuation and ultimately may even lead to instability. The conventional solution is to low pass filter the measured speed, but this lowers dynamic control performance...

  11. Electrochemical Hydrogen Compressor

    Lipp, Ludwig [FuelCell Energy, Inc., Torrington, CT (United States)

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  12. The design and development of an oil-free compressor for Spacelab Refrigerator/Freezer

    Hye, A.

    1984-01-01

    Design features and test results of an oil-free compressor developed for Spacelab Mission-4 Refrigerator/Freezer are detailed. The compressor has four identical pistons activated by a common eccentric shaft, operated by a brushless dc motor at 1300 rpm. The stroke of each piston is 0.28 cm, with the piston ends connected to the shaft by means of sealed needle bearings, eliminating the ned for oil. The mass flow rates produced by the compressor are by over 100 percent higher compared to the original Amfridge unit. Test results show that the compressor can meet the Spacelab refrigerator/freezer requirements.

  13. Speed control of permanent magnet excitation transverse flux linear motor by using adaptive neuro-fuzzy controller

    Hasanien, Hany M., E-mail: Hanyhasanien@ieee.or [Dept. of Elec. Power and Machines, Faculty of Eng., Ain-shams Univ. Cairo (Egypt); Muyeen, S.M. [Department of Electrical Engineering, Petroleum Institute, Abu Dhabi (United Arab Emirates); Tamura, Junji [Department of EEE, Kitami Institute of Technology, 165 Koen Cho, Kitami 090-8507, Hokkaido (Japan)

    2010-12-15

    This paper presents a novel adaptive neuro-fuzzy controller applies on transverse flux linear motor for controlling its speed. The proposed controller presents fuzzy logic controller with self tuning scaling factors based on artificial neural network structure. It has two input variables and one control output variable. Firstly the fuzzy logic control rules are described then NN architecture is represented to self tune the output scaling factors of the controller. The application of this control technique represents the novelty of work, where this algorithm has so far not been stated before for this type of drives. This methodology solves the problem of nonlinearities and load changes of TFLM drives. The dynamic response of the motor is studied under the rated load condition as well as load disturbances. The proposed controller ensures fast and accurate dynamic response with an excellent steady state performance. The dynamic response of the motor with the proposed controller is compared with PI and adaptive NN controllers. It is found that the proposed controller gives better and faster response from the viewpoint of overshoot and settling time. Matlab/Simulink tool is used for this dynamic simulation study.

  14. Lift force fluctuations of magnetically levitated vehicles with an integrated synchronous linear motor and their significance for the technical security

    Mnich, P; Huebner, K D

    1980-07-15

    In this paper the influence of the motor current on the magnetic force is investigated by an analytical method. With the integrated synchronous linear motor the reactions of the current sheet on the excitation field are depending on the pole angle and the amplitude of the current sheet. For an undisturbed operation - current sheet and induction wave in phase - the influence of the motor current on the magnetic force can be neglected. In case of a disturbed performance, i.e. when the pole angle is changing periodically, fluctuations of the magnetic force will be found. This effect has to be compensated by a reserve magnetic force in the levitation control. With the technical data for the new magnetic levitation pilots plants (International Traffic Fair 1979 at Hamburg and Transrapid - Pilot Plant Emsland) the stated relations are evaluated. Approximated relations for the levitation force are derived. For comparison, a finite-difference computer programme from the 'Institut fuer elektrische Maschinen, Antriebe und Bahnen, Technische Universitaet Braunschweig' is applied. The approximated relations developed in this paper are verified - with a sufficient precision - by the numerical calculations.

  15. Bio-inspired piezoelectric linear motor driven by a single-phase harmonic wave with an asymmetric stator.

    Pan, Qiaosheng; Miao, Enming; Wu, Bingxuan; Chen, Weikang; Lei, Xiujun; He, Liangguo

    2017-07-01

    A novel, bio-inspired, single-phase driven piezoelectric linear motor (PLM) using an asymmetric stator was designed, fabricated, and tested to avoid mode degeneracy and to simplify the drive mechanism of a piezoelectric motor. A piezoelectric transducer composed of two piezoelectric stacks and a displacement amplifier was used as the driving element of the PLM. Two simple and specially designed claws performed elliptical motion. A numerical simulation was performed to design the stator and determine the feasibility of the design mechanism of the PLM. Moreover, an experimental setup was built to validate the working principles, as well as to evaluate the performance, of the PLM. The prototype motor outputs a no-load speed of 233.7 mm/s at a voltage of 180 V p-p and a maximum thrust force of 2.3 N under a preload of 10 N. This study verified the feasibility of the proposed design and provided a method to simplify the driving harmonic signal and structure of PLMs.

  16. Optimal design of a double-sided linear motor with a multi-segmented trapezoidal magnet array for a high precision positioning system

    Lee, Moon G.; Gweon, Dae-Gab

    2004-01-01

    A comparative analysis is performed for linear motors adopting conventional and multi-segmented trapezoidal (MST) magnet arrays, respectively, for a high-precision positioning system. The proposed MST magnet array is a modified version of a Halbach magnet array. The MST array has trapezoidal magnets with variable shape and dimensions while the Halbach magnet array generally has a rectangular magnet with identical dimensions. We propose a new model that can describe the magnetic field resulting from the complex-shaped magnets. The model can be applied to both MST and conventional magnet arrays. Using the model, a design optimization of the two types of linear motors is performed and compared. The magnet array with trapezoidal magnets can produce more force than one with rectangular magnets when they are arrayed in a linear motor where there is a yoke with high permeability. After the optimization and comparison, we conclude that the linear motor with the MST magnet array can generate more actuating force per volume than the motor with the conventional array. In order to satisfy the requirements of next generation systems such as high resolution, high speed, and long stroke, the use of a linear motor with a MST array as an actuator in a high precision positioning system is recommended from the results obtained here

  17. MODELING OF EQUIVALENT STIFFNESS OF A MAGNETIC SPRING OF VIBRATION EXCITER BASED ON COAXIAL-LINEAR MOTOR

    G.M. Golenkov

    2015-12-01

    Full Text Available Purpose. The research of the influence of value and direction of current on the equivalent spring magnetic force based on coaxial-linear motor (CLM – MS. Methodology. We carried out investigation of the equivalent harshness of magnetic spring with determination of electromechanical propulsion performance characteristics by the methods of computer modeling and experimental research of physical model of CLM – MS. The modeling of magnetic spring of CLM – MS is carried out by the finite-element method. The challenge is met as an axisymmetric challenge in cylindrical co-ordinates in magnetostatic approach. The experimental investigattion of the propulsion performance characteristics of magnetic spring is carried out on the test bench. Results. After the computer modeling and the experimental investigation of the electromechanical propulsion performance characteristics of magnetic spring the expressions of equivalent stiffness coefficient depending on the current in winding are obtained. The results of computer modeling are confirmed experimentally. Originality. The determination of equivalent stiffness coefficient of magnetic spring of vibration exciter based on coaxial-linear motor. Practical value. The obtained determination of equivalent stiffness coefficient of magnetic spring may be used in process of designing of vibration machines with devices for change of natural oscillation frequency.

  18. RF Energy Compressor

    Farkas, Z.D.

    1980-02-01

    The RF Energy Compressor, REC described here, transforms cw rf into periodic pulses using an energy storage cavity, ESC, whose charging is controlled by 180 0 bi-phase modulation, PSK, and external Q switching, βs. Compression efficiency, C/sub e/, of 100% can be approached at any compression factor C/sub f/

  19. Comparisons between designs for single-sided linear electric motors: Homopolar synchronous and induction

    Nondahl, T. A.; Richter, E.

    1980-09-01

    A design study of two types of single sided (with a passive rail) linear electric machine designs, namely homopolar linear synchronous machines (LSM's) and linear induction machines (LIM's), is described. It is assumed the machines provide tractive effort for several types of light rail vehicles and locomotives. These vehicles are wheel supported and require tractive powers ranging from 200 kW to 3735 kW and top speeds ranging from 112 km/hr to 400 km/hr. All designs are made according to specified magnetic and thermal criteria. The LSM advantages are a higher power factor, much greater restoring forces for track misalignments, and less track heating. The LIM advantages are no need to synchronize the excitation frequency precisely to vehicle speed, simpler machine construction, and a more easily anchored track structure. The relative weights of the two machine types vary with excitation frequency and speed; low frequencies and low speeds favor the LSM.

  20. Complex motor task associated with non-linear BOLD responses in cerebro-cortical areas and cerebellum.

    Alahmadi, Adnan A S; Samson, Rebecca S; Gasston, David; Pardini, Matteo; Friston, Karl J; D'Angelo, Egidio; Toosy, Ahmed T; Wheeler-Kingshott, Claudia A M

    2016-06-01

    Previous studies have used fMRI to address the relationship between grip force (GF) applied to an object and BOLD response. However, whilst the majority of these studies showed a linear relationship between GF and neural activity in the contralateral M1 and ipsilateral cerebellum, animal studies have suggested the presence of non-linear components in the GF-neural activity relationship. Here, we present a methodology for assessing non-linearities in the BOLD response to different GF levels, within primary motor as well as sensory and cognitive areas and the cerebellum. To be sensitive to complex forms, we designed a feasible grip task with five GF targets using an event-related visually guided paradigm and studied a cohort of 13 healthy volunteers. Polynomial functions of increasing order were fitted to the data. (1) activated motor areas irrespective of GF; (2) positive higher-order responses in and outside M1, involving premotor, sensory and visual areas and cerebellum; (3) negative correlations with GF, predominantly involving the visual domain. Overall, our results suggest that there are physiologically consistent behaviour patterns in cerebral and cerebellar cortices; for example, we observed the presence of a second-order effect in sensorimotor areas, consistent with an optimum metabolic response at intermediate GF levels, while higher-order behaviour was found in associative and cognitive areas. At higher GF levels, sensory-related cortical areas showed reduced activation, interpretable as a redistribution of the neural activity for more demanding tasks. These results have the potential of opening new avenues for investigating pathological mechanisms of neurological diseases.

  1. Persistent current analysis of superconducting coils in a linear synchronous motor for maglev passenger transport system. Fujoshiki tetsudoyo linear doki motor ni okeru teijisoku mode chodendo coil denryu no kaiseki

    Azusawa, T [Toshiba Corp., Tokyo (Japan)

    1994-05-20

    The simple analysis method of persistent current induced in on-board superconducting coils was proposed for the vehicle of a superconducting magnetically-suspended train which is running in the magnetic field generated by armature coil current of a linear synchronous motor installed along a guideway, and the performance of the method is discussed through calculation based on typical models. As fluctuation of persistent current due to running was calculated with various parameter values under a normal running condition, fluctuation of persistent current induced was less then 1% of an initial magnetomotive force, having no adverse effect on the stability and reliability of superconducting magnets. Electromagnetic forces under a normal running condition could be predicted accurately enough by relatively easy-to-calculate constant current mode analysis. Double-layered armature coils were preferred to single-layered ones to enhance the stability of superconducting magnets by reducing fluctuation of persistent current. 10 refs., 8 figs., 1 tab.

  2. Body mass index and motor coordination: Non-linear relationships in children 6-10 years.

    Lopes, V P; Malina, R M; Maia, J A R; Rodrigues, L P

    2018-05-01

    Given the concern for health-related consequences of an elevated body mass index (BMI; obesity), the potential consequences of a low BMI in children are often overlooked. The purpose was to evaluate the relationship between the BMI across its entire spectrum and motor coordination (MC) in children 6-10 years. Height, weight, and MC (Körperkoordinationstest für Kinder, KTK test battery) were measured in 1,912 boys and 1,826 girls of 6-10 years of age. BMI (kg/m 2 ) was calculated. KTK scores for each of the four tests were also converted to a motor quotient (MQ). One-way ANOVA was used to test differences in the BMI, individual test items, and MQ among boys and girls within age groups. Sex-specific quadratic regressions of individual KTK items and the MQ on the BMI were calculated. Girls and boys were also classified into four weight status groups using International Obesity Task Force criteria: thin, normal, overweight, and obese. Differences in specific test items and MQ between weight status groups were evaluated by age group in each sex. Thirty-one percent of the sample was overweight or obese, whereas 5% was thin. On average, normal weight children had the highest MQ in both sexes across the age range with few exceptions. Overweight/obese children had a lower MQ than normal weight and thin children. The quadratic regression lines generally presented an inverted parabolic relationship between the BMI and MC and suggested a decrease in MC with an increase in the BMI. In general, BMI shows a curvilinear, inverted parabolic relationship with MC in children 6-10 years. © 2018 John Wiley & Sons Ltd.

  3. Centrifugal compressor case study

    Eckert, B.

    2010-10-15

    Three centrifugal compressors at a pipeline station were retrofitted with higher head impellers in 2008. The owners of the station experienced vibration problems over the following 2 years that caused transmitter and position failures that were assumed to be flow-induced pulsations. A vibration and pulsation analysis indicated that the shell mode piping vibration excited by the blade pass pulsation was responsible for the failures. This study outlined factors that contributed to the vibration problem. Interferences between the compressor and shell mode piping natural frequencies were predicted, and potential excitation sources were examined. The study demonstrated how centrifugal vibration analyses can be used during the design phase to avoid costly adjustments. Recommendations included the addition of stiffeners to alter the shell modes, and the addition of constrained layer damping material to reduce resonant responses. 2 refs., 1 tab., 12 figs.

  4. NASA Glenn's Single-Stage Axial Compressor Facility Upgraded

    Brokopp, Richard A.

    2004-01-01

    NASA Glenn Research Center's Single-Stage Axial Compressor Facility was upgraded in fiscal year 2003 to expand and improve its research capabilities for testing high-speed fans and compressors. The old 3000-hp drive motor and gearbox were removed and replaced with a refurbished 7000-hp drive motor and gearbox, with a maximum output speed of 21,240 rpm. The higher horsepower rating permits testing of fans and compressors with higher pressure ratio or higher flow. A new inline torquemeter was installed to provide an alternate measurement of fan and compressor efficiency, along with the standard pressure and temperature measurements. A refurbished compressor bearing housing was also installed with bidirectional rotation capability, so that a variety of existing hardware could be tested. Four new lubrication modules with backup capability were installed for the motor, gearbox, torquemeter, and compressor bearing housing, so that in case the primary pump fails, the backup will prevent damage to the rotating hardware. The combustion air supply line for the facility inlet air system was activated to provide dry air for repeatable inlet conditions. New flow conditioning hardware was installed in the facility inlet plenum tank, which greatly reduced the inlet turbulence. The new inlet can also be easily modified to accommodate 20- or 22-in.-diameter fans and compressors, so a variety of existing hardware from other facilities (such as Glenn's 9- by 15-Foot Low-Speed Wind Tunnel) can be tested in the Single-Stage Axial Compressor Facility. An exhaust line was also installed to provide bleed capability to remove the inlet boundary layer. To improve the operation and control of the facility, a new programmable logic controller (PLC) was installed to upgrade from hardwired relay logic to software logic. The PLC also enabled the usage of human-machine interface software to allow for easier operation of the facility and easier reconfiguration of the facility controls when

  5. The operation of a single-sided linear induction motor with squirrel-cage and solid-steel reaction rails

    Eastham, A. R.; Katz, R. M.

    1980-09-01

    Two test programs have been conducted to evaluate the performance of a single-sided linear induction motor with a squirrel-cage reaction rail and with a solid steel reaction rail. A 1.73-m-long six-pole stator interacted with the rails mounted on the rim of a 7.6-m-diam wheel. A 64-channel data acquisition system allowed tests to be performed over a wide range of operating conditions at speeds up to 20 m/sec. Typical test results which compare and contrast the mechanical, electrical and magnetic behavior of the SLIMs are presented. The test data are being used to assess the SLIM as an integrated suspension/propulsion system and for other transportation applications.

  6. Preliminary Design and Investigation of Integrated Compressor with Composite Material Wheel

    Wang, Jifeng; Müller, Norbert

    2012-06-01

    An integrated water vapor compressor with composite material wheel is developed and strength analysis using FEM is presented. The design of wound composite material allows for integrating all rotating parts of the drive that may simply reduce to only the rotor of the electrical motor, since no drive shaft is required anymore. This design can reduce the number of parts and mass, which is convenient for engineers to maintain the compressor. The electrical motors are brushless DC motors operating through a frequency drive and apply a torque on the wheels through the materials bonded in the wheel shrouds. This system allows a large amount of compression to be produced in a multi-stage compression setup. To determine the stress and vibration characteristics of this integrated compressor, numerical analysis is carried out using FEM. The simulation result shows that the integrated compressor with composite material wheel can be used in a chiller system where water as a refrigerant.

  7. Three dimensional force prediction in a model linear brushless dc motor

    Moghani, J.S.; Eastham, J.F.; Akmese, R.; Hill-Cottingham, R.J. (Univ. of Bath (United Kingdom). School of Electronic and Electric Engineering)

    1994-11-01

    Practical results are presented for the three axes forces produced on the primary of a linear brushless dc machine which is supplied from a three-phase delta-modulated inverter. Conditions of both lateral alignment and lateral displacement are considered. Finite element analysis using both two and three dimensional modeling is compared with the practical results. It is shown that a modified two dimensional model is adequate, where it can be used, in the aligned position and that the full three dimensional method gives good results when the machine is axially misaligned.

  8. Linear and nonlinear auditory response properties of interneurons in a high-order avian vocal motor nucleus during wakefulness.

    Raksin, Jonathan N; Glaze, Christopher M; Smith, Sarah; Schmidt, Marc F

    2012-04-01

    Motor-related forebrain areas in higher vertebrates also show responses to passively presented sensory stimuli. However, sensory tuning properties in these areas, especially during wakefulness, and their relation to perception, are poorly understood. In the avian song system, HVC (proper name) is a vocal-motor structure with auditory responses well defined under anesthesia but poorly characterized during wakefulness. We used a large set of stimuli including the bird's own song (BOS) and many conspecific songs (CON) to characterize auditory tuning properties in putative interneurons (HVC(IN)) during wakefulness. Our findings suggest that HVC contains a diversity of responses that vary in overall excitability to auditory stimuli, as well as bias in spike rate increases to BOS over CON. We used statistical tests to classify cells in order to further probe auditory responses, yielding one-third of neurons that were either unresponsive or suppressed and two-thirds with excitatory responses to one or more stimuli. A subset of excitatory neurons were tuned exclusively to BOS and showed very low linearity as measured by spectrotemporal receptive field analysis (STRF). The remaining excitatory neurons responded well to CON stimuli, although many cells still expressed a bias toward BOS. These findings suggest the concurrent presence of a nonlinear and a linear component to responses in HVC, even within the same neuron. These characteristics are consistent with perceptual deficits in distinguishing BOS from CON stimuli following lesions of HVC and other song nuclei and suggest mirror neuronlike qualities in which "self" (here BOS) is used as a referent to judge "other" (here CON).

  9. Using a generalized linear mixed model approach to explore the role of age, motor proficiency, and cognitive styles in children's reach estimation accuracy.

    Caçola, Priscila M; Pant, Mohan D

    2014-10-01

    The purpose was to use a multi-level statistical technique to analyze how children's age, motor proficiency, and cognitive styles interact to affect accuracy on reach estimation tasks via Motor Imagery and Visual Imagery. Results from the Generalized Linear Mixed Model analysis (GLMM) indicated that only the 7-year-old age group had significant random intercepts for both tasks. Motor proficiency predicted accuracy in reach tasks, and cognitive styles (object scale) predicted accuracy in the motor imagery task. GLMM analysis is suitable to explore age and other parameters of development. In this case, it allowed an assessment of motor proficiency interacting with age to shape how children represent, plan, and act on the environment.

  10. Bayesian integration and non-linear feedback control in a full-body motor task.

    Stevenson, Ian H; Fernandes, Hugo L; Vilares, Iris; Wei, Kunlin; Körding, Konrad P

    2009-12-01

    A large number of experiments have asked to what degree human reaching movements can be understood as being close to optimal in a statistical sense. However, little is known about whether these principles are relevant for other classes of movements. Here we analyzed movement in a task that is similar to surfing or snowboarding. Human subjects stand on a force plate that measures their center of pressure. This center of pressure affects the acceleration of a cursor that is displayed in a noisy fashion (as a cloud of dots) on a projection screen while the subject is incentivized to keep the cursor close to a fixed position. We find that salient aspects of observed behavior are well-described by optimal control models where a Bayesian estimation model (Kalman filter) is combined with an optimal controller (either a Linear-Quadratic-Regulator or Bang-bang controller). We find evidence that subjects integrate information over time taking into account uncertainty. However, behavior in this continuous steering task appears to be a highly non-linear function of the visual feedback. While the nervous system appears to implement Bayes-like mechanisms for a full-body, dynamic task, it may additionally take into account the specific costs and constraints of the task.

  11. Bayesian integration and non-linear feedback control in a full-body motor task.

    Ian H Stevenson

    2009-12-01

    Full Text Available A large number of experiments have asked to what degree human reaching movements can be understood as being close to optimal in a statistical sense. However, little is known about whether these principles are relevant for other classes of movements. Here we analyzed movement in a task that is similar to surfing or snowboarding. Human subjects stand on a force plate that measures their center of pressure. This center of pressure affects the acceleration of a cursor that is displayed in a noisy fashion (as a cloud of dots on a projection screen while the subject is incentivized to keep the cursor close to a fixed position. We find that salient aspects of observed behavior are well-described by optimal control models where a Bayesian estimation model (Kalman filter is combined with an optimal controller (either a Linear-Quadratic-Regulator or Bang-bang controller. We find evidence that subjects integrate information over time taking into account uncertainty. However, behavior in this continuous steering task appears to be a highly non-linear function of the visual feedback. While the nervous system appears to implement Bayes-like mechanisms for a full-body, dynamic task, it may additionally take into account the specific costs and constraints of the task.

  12. Fairchild 7B compressor model

    Foster, R.E.; Neely, R.S.

    1987-01-01

    The Fairchild 7B centrifugal compressor used in the X-326 isotopic ''top'' cascade at the Portsmouth Gaseous Diffusion Plant has been modeled using a proprietary computer code called COMPAL by Concepts E.T.I., Inc. of Norwich, VT. The 7B compressor is described and some results of the modeling calculations are presented. Performance characteristics curves (PR/sub b/vs. flow and PR/sub a/) are included for UF 6 gas for two compressor inlet temperatures

  13. Linear associations between clinically assessed upper motor neuron disease and diffusion tensor imaging metrics in amyotrophic lateral sclerosis.

    Woo, John H; Wang, Sumei; Melhem, Elias R; Gee, James C; Cucchiara, Andrew; McCluskey, Leo; Elman, Lauren

    2014-01-01

    To assess the relationship between clinically assessed Upper Motor Neuron (UMN) disease in Amyotrophic Lateral Sclerosis (ALS) and local diffusion alterations measured in the brain corticospinal tract (CST) by a tractography-driven template-space region-of-interest (ROI) analysis of Diffusion Tensor Imaging (DTI). This cross-sectional study included 34 patients with ALS, on whom DTI was performed. Clinical measures were separately obtained including the Penn UMN Score, a summary metric based upon standard clinical methods. After normalizing all DTI data to a population-specific template, tractography was performed to determine a region-of-interest (ROI) outlining the CST, in which average Mean Diffusivity (MD) and Fractional Anisotropy (FA) were estimated. Linear regression analyses were used to investigate associations of DTI metrics (MD, FA) with clinical measures (Penn UMN Score, ALSFRS-R, duration-of-disease), along with age, sex, handedness, and El Escorial category as covariates. For MD, the regression model was significant (p = 0.02), and the only significant predictors were the Penn UMN Score (p = 0.005) and age (p = 0.03). The FA regression model was also significant (p = 0.02); the only significant predictor was the Penn UMN Score (p = 0.003). Measured by the template-space ROI method, both MD and FA were linearly associated with the Penn UMN Score, supporting the hypothesis that DTI alterations reflect UMN pathology as assessed by the clinical examination.

  14. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  15. Mode change design for capacity modulation in reciprocating compressor

    Bae, Young Ju; Kim, Jin Kook; Kim, Jong Bong; Chang, Young June

    2008-01-01

    Due to environmental issues, the development of low energy consumption products has become one of the main topics in the home appliance industry. The energy consumption of a refrigerator depends on the efficiency of its compressor as well as on the refrigerator cycle design, such as the capacity modulation. This study features the design of a novel capacity modulation reciprocating compressor, i.e., two-step capacity modulation (TCM). In a TCM compressor, capacity modulation is achieved by changing the dead volume in the cylinder. Instead of a concentric sleeve, an eccentric sleeve is used to change the dead volume for the clockwise and counterclockwise rotation of a motor. For stable capacity modulation, a new latching system with a key, a spring, and an eccentric sleeve is introduced, and the mode change reliability is verified by dynamic analysis

  16. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  17. Cooled-Spool Piston Compressor

    Morris, Brian G.

    1994-01-01

    Proposed cooled-spool piston compressor driven by hydraulic power and features internal cooling of piston by flowing hydraulic fluid to limit temperature of compressed gas. Provides sufficient cooling for higher compression ratios or reactive gases. Unlike conventional piston compressors, all parts of compressed gas lie at all times within relatively short distance of cooled surface so that gas cooled more effectively.

  18. Low-Vibration Oscillating Compressor

    Studer, P. A.

    1984-01-01

    Oscillating compressor momentum compensated: produces little vibration in its supporting structure. Compressure requires no lubrication and virtually free of wear. Compresses working fluids such as helium, nitrogen or chlorfluorocarbons for Stirling-cycle refrigeration or other purposes. Compressor includes two mutually opposed ferromagnetic pistons of same shape and mass. Electromagnetic flux links both pistons, causing magnetic attraction between them.

  19. NASA low speed centrifugal compressor

    Hathaway, Michael D.

    1990-01-01

    The flow characteristics of a low speed centrifugal compressor were examined at NASA Lewis Research Center to improve understanding of the flow in centrifugal compressors, to provide models of various flow phenomena, and to acquire benchmark data for three dimensional viscous flow code validation. The paper describes the objectives, test facilities' instrumentation, and experiment preliminary comparisons.

  20. Centrifugal-reciprocating compressor

    Higa, W. H. (Inventor)

    1984-01-01

    A centrifugal compressor is described which includes at least one pair of cylinders arranged in coaxial alignment and supported for angular displacement about a common axis of rotation normally disecting a common longitudinal axis of symmetry for the cylinders. The cylinders are characterized by ported closures located at the mutually remote ends thereof through which the cylinders are charged and discharged, and a pair of piston heads seated within the cylinders and supported for floating displacement in compressive strokes in response to unidirectional angular displacement imparted to the cylinders.

  1. Modeling of scroll compressors - Improvements

    Duprez, Marie-Eve; Dumont, Eric; Frere, Marc [Thermodynamics Department, Universite de Mons - Faculte Polytechnique, 31 bd Dolez, 7000 Mons (Belgium)

    2010-06-15

    This paper presents an improvement of the scroll compressors model previously published by. This improved model allows the calculation of refrigerant mass flow rate, power consumption and heat flow rate that would be released at the condenser of a heat pump equipped with the compressor, from the knowledge of operating conditions and parameters. Both basic and improved models have been tested on scroll compressors using different refrigerants. This study has been limited to compressors with a maximum electrical power of 14 kW and for evaporation temperatures ranging from -40 to 15 C and condensation temperatures from 10 to 75 C. The average discrepancies on mass flow rate, power consumption and heat flow rate are respectively 0.50%, 0.93% and 3.49%. Using a global parameter determination (based on several refrigerants data), this model can predict the behavior of a compressor with another fluid for which no manufacturer data are available. (author)

  2. AIRGAP MAGNETIC INDUCTION DISTRIBUTION IN A COAXIALLY-LINEAR SYNCHRONOUS MOTOR WITH AXIAL AND RADIAL DIRECTION OF THE RUNNER PERMANENT MAGNETS MAGNETIZATION

    Abbasian Mohsen

    2013-02-01

    Full Text Available Results of theoretical and experimental research on magnetic induction distribution in the air gap of a coaxially-linear synchronous motor with reciprocal motion within the pole pitch and axial and radial direction of the permanent magnets magnetization are presented.

  3. Noise evaluation of automotive A/C compressor

    Metwally, Sameh M.; Khalil, Mohamed I.; Abouel-seoud, Shawki A. [Automotive and Tractors Dept., Faculty of Engineering, Helwan University, Cairo (Egypt)

    2011-07-01

    Passenger compartment's interior noise and thermal performance are essential criteria for the driving comfort of vehicles. The air-conditioning system influences both field of comfort. It creates comfortable thermal conditions. On the other hand, the noise radiation of the air-condition system's components can be annoying. The blower, the air distribution ducts and the registers affect air rush noise. In some cases, the refrigerant flow creates hissing noise. Such noise has a great influence on vehicle acoustical comfort and on overall quality perception of a vehicle Therefore, the acoustic performance of air-condition compressors become more important for passenger comfort. At engine idling and at extreme temperatures the air-condition compressor can be audible as the significant sound source. However, the aim of this paper is to quantify air-borne noise characteristics of vehicle air-condition compressor. A simulated experimental model comprises a small wooden box with dimensions of 0.5 x 0.5 x 0.5 m represented the principle of hemi-anechoic room was designed and acoustic characteristics of the sound field inside the box were determined. The air-condition compressor characteristics parameters considered in this paper are fan position and electric motor speed. In addition, a single number of the air column natural frequency is calculated. The results indicate that significant information can be obtained in order to investigate the vehicle air-condition compressor and consequently improve the vehicle interior quietness.

  4. The monomeric, tetrameric, and fibrillar organization of Fib: the dynamic building block of the bacterial linear motor of Spiroplasma melliferum BC3.

    Cohen-Krausz, Sara; Cabahug, Pamela C; Trachtenberg, Shlomo

    2011-07-08

    Spiroplasmas belong to the class Mollicutes, representing the minimal, free-living, and self-replicating forms of life. Spiroplasmas are helical wall-less bacteria and the only ones known to swim by means of a linear motor (rather than the near-universal rotary bacterial motor). The linear motor follows the shortest path along the cell's helical membranal tube. The motor is composed of a flat monolayered ribbon of seven parallel fibrils and is believed to function in controlling cell helicity and motility through dynamic, coordinated, differential length changes in the fibrils. The latter cause local perturbations of helical symmetry, which are essential for net directional displacement in environments with a low Reynolds number. The underlying fibrils' core building block is a circular tetramer of the 59-kDa protein Fib. The fibrils' differential length changes are believed to be driven by molecular switching of Fib, leading consequently to axial ratio and length changes in tetrameric rings. Using cryo electron microscopy, diffractometry, single-particle analysis of isolated ribbons, and sequence analyses of Fib, we determined the overall molecular organization of the Fib monomer, tetramer, fibril, and linear motor of Spiroplasma melliferum BC3 that underlies cell geometry and motility. Fib appears to be a bidomained molecule, of which the N-terminal half is apparently a globular phosphorylase. By a combination of reversible rotation and diagonal shift of Fib monomers, the tetramer adopts either a cross-like nonhanded conformation or a ring-like handed conformation. The sense of Fib rotation may determine the handedness of the linear motor and, eventually, of the cell. A further change in the axial ratio of the ring-like tetramers controls fibril lengths and the consequent helical geometry. Analysis of tetramer quadrants from adjacent fibrils clearly demonstrates local differential fibril lengths. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Optimising the refrigeration cycle with a two-stage centrifugal compressor and a flash intercooler

    Roeyttae, Pekka; Turunen-Saaresti, Teemu; Honkatukia, Juha [Lappeenranta University of Technology, Laboratory of Energy and Environmental Technology, PO Box 20, 53851 Lappeenranta (Finland)

    2009-09-15

    The optimisation of a refrigeration process with a two-stage centrifugal compressor and flash intercooler is presented in this paper. The two-stage centrifugal compressor stages are on the same shaft and the electric motor is cooled with the refrigerant. The performance of the centrifugal compressor is evaluated based on semi-empirical specific-speed curves and the effect of the Reynolds number, surface roughness and tip clearance have also been taken into account. The thermodynamic and transport properties of the working fluids are modelled with a real-gas model. The condensing and evaporation temperatures, the temperature after the flash intercooler, and cooling power have been chosen as fixed values in the process. The aim is to gain a maximum coefficient of performance (COP). The method of optimisation, the operation of the compressor and flash intercooler, and the method for estimating the electric motor cooling are also discussed in the article. (author)

  6. Mass distribution and spatial organization of the linear bacterial motor of Spiroplasma citri R8A2.

    Trachtenberg, Shlomo; Andrews, S Brian; Leapman, Richard D

    2003-03-01

    In the simple, helical, wall-less bacterial genus Spiroplasma, chemotaxis and motility are effected by a linear, contractile motor arranged as a flat cytoskeletal ribbon attached to the inner side of the membrane along the shortest helical line. With scanning transmission electron microscopy and diffraction analysis, we determined the hierarchical and spatial organization of the cytoskeleton of Spiroplasma citri R8A2. The structural unit appears to be a fibril, approximately 5 nm wide, composed of dimers of a 59-kDa protein; each ribbon is assembled from seven fibril pairs. The functional unit of the intact ribbon is a pair of aligned fibrils, along which pairs of dimers form tetrameric ring-like repeats. On average, isolated and purified ribbons contain 14 fibrils or seven well-aligned fibril pairs, which are the same structures observed in the intact cell. Scanning transmission electron microscopy mass analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified cytoskeletons indicate that the 59-kDa protein is the only constituent of the ribbons.

  7. Improvement of superconducting cylindrical linear induction motor; Chodendo entogata tan'ichiji rinia yudo mota no tokusei kaizen

    Kikuma, T.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)

    2000-05-29

    For the purpose of examining the characteristics (effect of stability and ac loss by the higher harmonic wave etc.) of an alternating current superconductivity winding under a real machine operating environment of the super-conductive AC machine vessel, authors produced a cylindrical shortness first linear guiding motor (SCLIM) which used the NbTi/CuNi super-conducting cable for the first excitation winding experimentally. In this study, the evaluation of the start up thrust and operation confirmation of the quenching detection protection circuit were carried out using the produced SCLIM. In the quenching detection protection control circuit, the first excitation winding was divided into an internal layer and an outer layer, and both layers were excited in the 2 layer division and a quenching detection protection circuit was installed on the 2 layers respectively. The circuit of a part of fact by this of the phase in which the quench was generated and observed was cut off, and the operation would be able to be continued in part of the remainder of the phase and other two phases. Here, it is to cut off the quenched phase from the circuit, when the phase current becomes zero, and the other effect on the phase is held as small as possible. (NEDO)

  8. Study on the CO2 electric driven fixed swash plate type compressor for eco-friendly vehicles

    Nam, Donglim; Kim, Kitae; Lee, Jehie; Kwon, Yunki; Lee, Geonho

    2017-08-01

    The purpose of this study is to experiment and to performance analysis about the electric-driven fixed swash plate compressor using alternate refrigerant(R744). Comprehensive simulation model for an electric driven compressor using CO2 for eco-friendly vehicle is presented. This model consists of compression model and dynamic model. The compression model included valve dynamics, leakage, and heat transfer models. And the dynamic model included frictional loss between piston ring and cylinder wall, frictional loss between shoe and swash plate, frictional loss of bearings, and electric efficiency. Especially, because the efficiency of an electric parts(motor and inverter) in the compressor affects the loss of the compressor, the dynamo test was performed. We made the designed compressor, and tested the performance of the compressor about the variety pressure conditions. Also we compared the performance analysis result and performance test result.

  9. Small Displacement, Long Life On-Orbit Compressor Design and Fabrication

    Gerlach, C. R.; Schroeder, E. C.; Deffenbaugh, D. D.; Masetta, J. P.

    1989-01-01

    The focus is the generation of technology and fabrication of prototype hardware applicable to seven Space Station compressor system applications. The compressors are of the single acting reciprocating piston type and, in general, may be termed miniature in size compared with normal commercially available equipment. The initial technology development is focused on improved valve designs, and the control of pulsations and heating effects in order to increase compressor efficiency and reduce cycle temperatures, thus permitting significantly increased stage pressure ratios. The initial test compressor was successfully operated at pressure ratios of up to 50:1, and this significant extension of allowable pressure ratio will result in a reduction of the number of required stages and, hence, total hardware thereby reducing system weight and volume. These experiments have also identified the need to employ low shaft speeds, on the order of 250 to 500 rpm, to enhance heat transfer and increase life. The prototype compressor currently being designed, is to be driven by a low-speed brushless dc motor sealed in a case common to the compressor drive mechanism case. The compressor and motor case will communicate with stage suction pressure so that any minor gas leakage past the piston rings will be returned to the suction. Emphasis in this prototype design is being placed on simplicity, durability, commonality of components, and high efficiency.

  10. A descrição do funcionamento de um motor Homopolar linear e suas aplicações: Ilustrando o funcionamento de um acelerador de partículas

    Doff, Adriano; Szmoski, Romeu M.

    2016-01-01

    Neste trabalho exploramos o potencial didático de um motor homopolar linear com o objetivo de ilustrar o princípio de funcionamento de um acelerador de partículas. A fim de estabelecer o mecanismo de funcionamento de um motor homopolar linear, consideramos uma analogia com a descrição de um motor homopolar rotatório, e partir deste apresentamos os princípios de funcionamento deste dispositivo e estabelecemos um limite teórico para a velocidade do motor linear. De posse dos dados gerados exper...

  11. Characterization of Multiflux Axial Compressors

    Brasnarof, Daniel; Kyung Kyu-Hyung; Rivarola, Martin; Gonzalez Jose; Florido, Pablo; Orellano, Pablo; Bergallo, Juan

    2003-01-01

    In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant

  12. Compressor performance aerodynamics for the user

    Gresh, Theodore

    2001-01-01

    Compressor Performance is a reference book and CD-ROM for compressor design engineers and compressor maintenance engineers, as well as engineering students. The book covers the full spectrum of information needed for an individual to select, operate, test and maintain axial or centrifugal compressors. It includes basic aerodynamic theory to provide the user with the ""how's"" and ""why's"" of compressor design. Maintenance engineers will especially appreciate the troubleshooting guidelines offered. Includes many example problems and reference data such as gas propert

  13. Entropic potential field formed for a linear-motor protein near a filament: Statistical-mechanical analyses using simple models.

    Amano, Ken-Ichi; Yoshidome, Takashi; Iwaki, Mitsuhiro; Suzuki, Makoto; Kinoshita, Masahiro

    2010-07-28

    We report a new progress in elucidating the mechanism of the unidirectional movement of a linear-motor protein (e.g., myosin) along a filament (e.g., F-actin). The basic concept emphasized here is that a potential field is entropically formed for the protein on the filament immersed in solvent due to the effect of the translational displacement of solvent molecules. The entropic potential field is strongly dependent on geometric features of the protein and the filament, their overall shapes as well as details of the polyatomic structures. The features and the corresponding field are judiciously adjusted by the binding of adenosine triphosphate (ATP) to the protein, hydrolysis of ATP into adenosine diphosphate (ADP)+Pi, and release of Pi and ADP. As the first step, we propose the following physical picture: The potential field formed along the filament for the protein without the binding of ATP or ADP+Pi to it is largely different from that for the protein with the binding, and the directed movement is realized by repeated switches from one of the fields to the other. To illustrate the picture, we analyze the spatial distribution of the entropic potential between a large solute and a large body using the three-dimensional integral equation theory. The solute is modeled as a large hard sphere. Two model filaments are considered as the body: model 1 is a set of one-dimensionally connected large hard spheres and model 2 is a double helical structure formed by two sets of connected large hard spheres. The solute and the filament are immersed in small hard spheres forming the solvent. The major findings are as follows. The solute is strongly confined within a narrow space in contact with the filament. Within the space there are locations with sharply deep local potential minima along the filament, and the distance between two adjacent locations is equal to the diameter of the large spheres constituting the filament. The potential minima form a ringlike domain in model 1

  14. Free piston inertia compressor

    Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.

    A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

  15. Magentically actuated compressor

    Evans, J.; Studer, P. A. (Inventor)

    1985-01-01

    A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprises a pair of identical opposing ferromagnetic pistons located in a housing and between a gas spring including a sealed volume of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons to generate a compression wave which can be vented to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons in such a fashion that the pistons are mutually attracted to one another. The mass of the pistons, in conjunction with the compressed gas between them, form a naturally resonant system which, when the pistons are electromagnetically energized, produces an oscillating compression wave in the entrapped fluid medium.

  16. Harmattan gas plant compressor conversion

    Temple, K. [Altagas Ltd., Calgary, AB (Canada)

    2009-07-01

    The Harmattan Gas Plant located near the town of Didsbury, Alberta has typical processing units such as amine treating, sulfur recovery, refrigeration, and dehydration. In 1999, a deep cut turbo expander train was added for the extraction of ethane and in 2003 a spec carbon dioxide unit was added. Since its construction in 1961, the plant has undergone many modifications. As such, the plant is a mix of new and old equipment. A 3500 kW Solar Centaur 50LS gas turbine compressor with waste heat recovery was installed at the plant in 2008. This paper reviewed the project from concept to execution and demonstrated how reciprocating compressors were economically replaced with a gas turbine. Altagas had an incentive to invest in the project to lower operating and maintenance costs. Altagas was able to economically replace aging reciprocating compressors with a single turbine driving a centrifugal compressor without any producer subsidies or contract revisions. 2 tabs., 5 figs.

  17. Dynamic modeling and simulation of an induction motor with adaptive backstepping design of an input-output feedback linearization controller in series hybrid electric vehicle

    Jalalifar Mehran

    2007-01-01

    Full Text Available In this paper using adaptive backstepping approach an adaptive rotor flux observer which provides stator and rotor resistances estimation simultaneously for induction motor used in series hybrid electric vehicle is proposed. The controller of induction motor (IM is designed based on input-output feedback linearization technique. Combining this controller with adaptive backstepping observer the system is robust against rotor and stator resistances uncertainties. In additional, mechanical components of a hybrid electric vehicle are called from the Advanced Vehicle Simulator Software Library and then linked with the electric motor. Finally, a typical series hybrid electric vehicle is modeled and investigated. Various tests, such as acceleration traversing ramp, and fuel consumption and emission are performed on the proposed model of a series hybrid vehicle. Computer simulation results obtained, confirm the validity and performance of the proposed IM control approach using for series hybrid electric vehicle.

  18. The Multiple Correspondence Analysis Method and Brain Functional Connectivity: Its Application to the Study of the Non-linear Relationships of Motor Cortex and Basal Ganglia.

    Rodriguez-Sabate, Clara; Morales, Ingrid; Sanchez, Alberto; Rodriguez, Manuel

    2017-01-01

    The complexity of basal ganglia (BG) interactions is often condensed into simple models mainly based on animal data and that present BG in closed-loop cortico-subcortical circuits of excitatory/inhibitory pathways which analyze the incoming cortical data and return the processed information to the cortex. This study was aimed at identifying functional relationships in the BG motor-loop of 24 healthy-subjects who provided written, informed consent and whose BOLD-activity was recorded by MRI methods. The analysis of the functional interaction between these centers by correlation techniques and multiple linear regression showed non-linear relationships which cannot be suitably addressed with these methods. The multiple correspondence analysis (MCA), an unsupervised multivariable procedure which can identify non-linear interactions, was used to study the functional connectivity of BG when subjects were at rest. Linear methods showed different functional interactions expected according to current BG models. MCA showed additional functional interactions which were not evident when using lineal methods. Seven functional configurations of BG were identified with MCA, two involving the primary motor and somatosensory cortex, one involving the deepest BG (external-internal globus pallidum, subthalamic nucleus and substantia nigral), one with the input-output BG centers (putamen and motor thalamus), two linking the input-output centers with other BG (external pallidum and subthalamic nucleus), and one linking the external pallidum and the substantia nigral. The results provide evidence that the non-linear MCA and linear methods are complementary and should be best used in conjunction to more fully understand the nature of functional connectivity of brain centers.

  19. Design elements and quantitative results of synchronous longstator linear motors for high-speed magnetic trains taking the TRANSRAPID test facility in Emsland as an example

    Fuerst, R [Industrieanlagen-Betriebsgesellschaft mbH, Magnetbahn-Versuchsanlage, Lathen/Ems (Germany)

    1996-12-31

    In German high-speed magnetic train technology, iron-clad synchronous long-stator linear motors of levitation stator design are used to propel and brake the vehicles. This paper uses the propulsion design of the Transrapid test facility in Emsland (TVE) to illustrate in practical terms the dimensioning parameters for thrust calculations and their interdependencies. The paper is based on description conventions common for rotating electrical machines and rail technology. (orig.)

  20. Small-sized linear accelerator of 2.5 MeV electrons with a local radiation shield for custom examination of freight transported by motor transport

    Baklanov, A.V.; Gavrish, Yu.N.; Klinov, A.P.; Krest'yaninov, A.S.; Nikolaev, V.M.; Fomin, L.P.; Linkenbach, H.A.; Geus, G.; Knospel, W.

    2001-01-01

    A new development of a small-sized linear accelerator of 2.5 MeV electrons with a local radiation protection is described. The accelerator is intended for movable facilities of radiation custom of the freight transported by motor transport. Main constructive solutions, mass and dimension characteristics and results of preliminary tests of the accelerator parameters and characteristics of radiation protection are presented [ru

  1. Fluctuations in isometric muscle force can be described by one linear projection of low-frequency components of motor unit discharge rates.

    Negro, Francesco; Holobar, Ales; Farina, Dario

    2009-12-15

    The aim of the study was to investigate the relation between linear transformations of motor unit discharge rates and muscle force. Intramuscular (wire electrodes) and high-density surface EMG (13 x 5 electrode grid) were recorded from the abductor digiti minimi muscle of eight healthy men during 60 s contractions at 5%, 7.5% and 10% of the maximal force. Spike trains of a total of 222 motor units were identified from the EMG recordings with decomposition algorithms. Principal component analysis of the smoothed motor unit discharge rates indicated that one component (first common component, FCC) described 44.2 +/- 7.5% of the total variability of the smoothed discharge rates when computed over the entire contraction interval and 64.3 +/- 10.2% of the variability when computed over 5 s intervals. When the FCC was computed from four or more motor units per contraction, it correlated with the force produced by the muscle (62.7 +/- 10.1%) by a greater degree (P FCC and the force signal increased up to 71.8 +/- 13.1% when the duration and the shape of the smoothing window for discharge rates were similar to the average motor unit twitch force. Moreover, the coefficients of variation (CoV) for the force and for the FCC signal were correlated in all subjects (R(2) range = 0.14-0.56; P measures on the tibialis anterior muscle of an additional eight subjects during contractions at forces up to 20% of the maximal force (e.g. FCC explained 59.8 +/- 11.0% of variability of the smoothed discharge rates). In conclusion, one signal captures most of the underlying variability of the low-frequency components of motor unit discharge rates and explains large part of the fluctuations in the motor output during isometric contractions.

  2. Satellite refrigerator compressors with the oil and moisture removal systems

    Satti, J.A.

    1983-08-01

    There are twenty-eight compressors installed around the Main Accelerator Ring in seven locations. Drawing 9140-ME-129720 shows the piping and the components schematic for four Mycom compressor skids per building with each having an independent oil and moisture removal system. The Mycom skids each consist of an oil injected screw compressor of 750 SCFM capacity with a 350 hp motor, oil pump, oil cooler, and oil separator. Helium gas returning from the heat exchanger train is compressed from 1 atm to 20 atm in the compressor. The compressed gas is then passed through the three coalescer de-mister where oil mist is separated from the helium gas. The helium gas then flows through the charcoal adsorber and molecular sieve where any residual oil vapor and water vapor are removed. The final stage of purification is the final filter which removes any remaining particulates from the compressed helium gas. The end product of this system is compressed and purified helium gas ready to be cooled down to cryogenic temperatures

  3. Control de velocidad del motor de indución empleando linealización por realimentación de estados Speed control of induction motor using state feedback linearization

    Eduardo Giraldo Suárez

    2009-01-01

    Full Text Available Este documento presenta la aplicación de la técnica de control no lineal clásica llamada linealización por realimentación de variables de estado. Se hace una aplicación en el motor de inducción, la variable a controlar es la velocidad del eje del motor, el sistema emplea el esquema de control vectorial para máquinas de corriente alterna desarrollado en las últimas décadas; este método es análogo a la técnica de control del motor de corriente directa. El modelo del motor de inducción se describe en el sistema de coordenadas de campo orientado del flujo de rotor y se muestra una introducción al producto y la derivada de Lie, empleados en el diseño del controlador no lineal.This articles shows the application of a classic non-linear control technique called "linearization by feedback of status variables." An application on the induction engine is made. Variable to be controlled is speed of the engine shaft. The system employs a vectorial control scheme for AC engines developed during the last decades. This is a method analogous to the DC engine control technique. Induction engine model is described in the guided field coordinate system of rotor flow. Introduction to the product and Lie derivative used for designing the non-linear controller are shown.

  4. Empirical Design Considerations for Industrial Centrifugal Compressors

    Cheng Xu

    2012-01-01

    Full Text Available Computational Fluid Dynamics (CFD has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

  5. Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line

    Gaul, Christopher J.

    2001-01-01

    The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

  6. 40 CFR 63.1012 - Compressor standards.

    2010-07-01

    ... is equipped with a system to capture and transport leakage from the compressor drive shaft seal to a... in the referencing subpart. (b) Seal system standard. Each compressor shall be equipped with a seal..., except as provided in § 63.1002(b) and paragraphs (e) and (f) of this section. Each compressor seal...

  7. 40 CFR 63.164 - Standards: Compressors.

    2010-07-01

    ... from the compressor drive shaft seal back to a process or a fuel gas system or to a control device that... compressor shall be equipped with a seal system that includes a barrier fluid system and that prevents... paragraphs (h) and (i) of this section. (b) Each compressor seal system as required in paragraph (a) of this...

  8. The numerical assessment of motion strategies for integrated linear motor during starting of a free-piston engine generator

    Razali Hanipah, M.; Razul Razali, Akhtar

    2017-10-01

    Free-piston engine generator (FPEG) provides a novel method for electrical power generation in hybrid electric vehicle applications with scarcely reported prototype development and testing. This paper is looking into the motion control strategy for motoring the FPEG during starting. There are two motion profiles investigated namely, trapezoidal velocity and Scurve velocity. Both motion profiles were investigated numerically and the results have shown that the S-curve motion can only achieve 80% of the stroke when operated at the proposed motoring speed of 10Hz.

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

    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.

  10. Numerical Calculation of the Flow in a Centrifugal Compressor Volute

    Seong, Seon Mo; Kang, Shin Hyoung; Cho, Kyung Seok; Kim, Woo June

    2007-01-01

    Flows in the centrifugal compressor volute with circular cross section are numerically investigated. The computational domain contained inlet passage, impeller, radial and axial diffuser, and volute. The volute grid for the calculation utilized a multi-block arrangement to form a butterfly grid and flow calculations are performed using commercial CFD software, CFX-TASCflow. The centrifugal compressor of this study has the inlet passage like steps and axial diffuser after radial diffuser because of the shape of the motor cooling fins and installation constraints. Due to this feature the swirling flow pattern is different from the other investigations. The loss in through the inlet passage was considerable and the flow inside volute is very complex and three dimensional with strong vortex and recirculation through volute tongue

  11. The Parkinsonian Subthalamic Network: Measures of Power, Linear, and Non-linear Synchronization and their Relationship to L-DOPA Treatment and OFF State Motor Severity.

    West, Timothy; Farmer, Simon; Berthouze, Luc; Jha, Ashwani; Beudel, Martijn; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Brown, Peter; Litvak, Vladimir

    2016-01-01

    In this paper we investigated the dopaminergic modulation of neuronal interactions occurring in the subthalamic nucleus (STN) during Parkinson's disease (PD). We utilized linear measures of local and long range synchrony such as power and coherence, as well as Detrended Fluctuation Analysis for Phase Synchrony (DFA-PS)- a recently developed non-linear method that computes the extent of long tailed autocorrelations present in the phase interactions between two coupled signals. Through analysis of local field potentials (LFPs) taken from the STN we seek to determine changes in the neurodynamics that may underpin the pathophysiology of PD in a group of 12 patients who had undergone surgery for deep brain stimulation. We demonstrate up modulation of alpha-theta (5-12 Hz) band power in response to L-DOPA treatment, whilst low beta band power (15-20 Hz) band-power is suppressed. We also find evidence for significant local connectivity within the region surrounding STN although there was evidence for its modulation via administration of L-DOPA. Further to this we present evidence for a positive correlation between the phase ordering of bilateral STN interactions and the severity of bradykinetic and rigidity symptoms in PD. Although, the ability of non-linear measures to predict clinical state did not exceed standard measures such as beta power, these measures may help identify the connections which play a role in pathological dynamics.

  12. Three-stage linear, split-Stirling cryocooler for 1 to 2K magnetic cold stage

    Longsworth, R.C.

    1993-08-01

    A long-life, linear, high efficiency 8K split Stirling cycle cryocooler was designed, built, and tested. The refrigerator is designed for cooling a 50 mW, 1.5K magnetic cold stage. Dual opposed piston compressors are driven by moving-coil linear motors. The three stage expander, although not completed, is also driven by a linear motor and is designed to produce 1 SW at 60K, 4W at 16K, and 1.2W at 8K. The cold regenerator employs a parallel gap construction for high efficiency. The key technology areas addressed include warm and cold flexible suspension bearings and a new cold regenerator geometry for high efficiency at 8K

  13. Non-linear Relationship between BOLD Activation and Amplitude of Beta Oscillations in the Supplementary Motor Area during Rhythmic Finger Tapping and Internal Timing

    Gompf, Florian; Pflug, Anja; Laufs, Helmut; Kell, Christian A.

    2017-01-01

    Functional imaging studies using BOLD contrasts have consistently reported activation of the supplementary motor area (SMA) both during motor and internal timing tasks. Opposing findings, however, have been shown for the modulation of beta oscillations in the SMA. While movement suppresses beta oscillations in the SMA, motor and non-motor tasks that rely on internal timing increase the amplitude of beta oscillations in the SMA. These independent observations suggest that the relationship between beta oscillations and BOLD activation is more complex than previously thought. Here we set out to investigate this rapport by examining beta oscillations in the SMA during movement with varying degrees of internal timing demands. In a simultaneous EEG-fMRI experiment, 20 healthy right-handed subjects performed an auditory-paced finger-tapping task. Internal timing was operationalized by including conditions with taps on every fourth auditory beat, which necessitates generation of a slow internal rhythm, while tapping to every auditory beat reflected simple auditory-motor synchronization. In the SMA, BOLD activity increased and power in both the low and the high beta band decreased expectedly during each condition compared to baseline. Internal timing was associated with a reduced desynchronization of low beta oscillations compared to conditions without internal timing demands. In parallel with this relative beta power increase, internal timing activated the SMA more strongly in terms of BOLD. This documents a task-dependent non-linear relationship between BOLD and beta-oscillations in the SMA. We discuss different roles of beta synchronization and desynchronization in active processing within the same cortical region. PMID:29249950

  14. Non-linear Relationship between BOLD Activation and Amplitude of Beta Oscillations in the Supplementary Motor Area during Rhythmic Finger Tapping and Internal Timing.

    Gompf, Florian; Pflug, Anja; Laufs, Helmut; Kell, Christian A

    2017-01-01

    Functional imaging studies using BOLD contrasts have consistently reported activation of the supplementary motor area (SMA) both during motor and internal timing tasks. Opposing findings, however, have been shown for the modulation of beta oscillations in the SMA. While movement suppresses beta oscillations in the SMA, motor and non-motor tasks that rely on internal timing increase the amplitude of beta oscillations in the SMA. These independent observations suggest that the relationship between beta oscillations and BOLD activation is more complex than previously thought. Here we set out to investigate this rapport by examining beta oscillations in the SMA during movement with varying degrees of internal timing demands. In a simultaneous EEG-fMRI experiment, 20 healthy right-handed subjects performed an auditory-paced finger-tapping task. Internal timing was operationalized by including conditions with taps on every fourth auditory beat, which necessitates generation of a slow internal rhythm, while tapping to every auditory beat reflected simple auditory-motor synchronization. In the SMA, BOLD activity increased and power in both the low and the high beta band decreased expectedly during each condition compared to baseline. Internal timing was associated with a reduced desynchronization of low beta oscillations compared to conditions without internal timing demands. In parallel with this relative beta power increase, internal timing activated the SMA more strongly in terms of BOLD. This documents a task-dependent non-linear relationship between BOLD and beta-oscillations in the SMA. We discuss different roles of beta synchronization and desynchronization in active processing within the same cortical region.

  15. FY 2000 report on the results of the technology development of energy use reduced machine tools, etc. Development of the linear motor system for realization of energy conservation and commercialization; 2000 nendo energy shiyo gorika kosaku kiki nado gijutsu kaihatsu seika hokokusho. Shoeneka to jitsuyoka wo jitsugensuru linear motor system no kaihatsu

    NONE

    2001-03-01

    In relation to the drive system of machine tools widely used as production facilities for automobiles, home electric appliances, etc., the R and D were made of a high efficiency linear motor system of which attention was paid to energy rationalization and environmental loads, and the FY 2000 results were summed up. In the study of the development of the system, studies were made not only on the lowering of heating, cost reduction and heightening of speed, but on the mechanism and control by which machine natural vibration can relatively be cut off, technology of damping for cutting vibration, technology to meet the deformation, etc. by cutting loads, sliding loads, and acceleration of accelerating/decelerating, technology to reduce the machine weight, etc. In the study of the basic technology of linear motor, the finite element method analysis was conducted on the typical linear motor. Concerning the control system, specs were studied which can deal with natural vibration and cutting vibration of the machine system. As to the development of the steel scale type linear encoder, scale sample for evaluation of basic characteristics was designed/trially manufactured. In the study of the detection optical system, the design/trial manufacture of photodiode array were made. (NEDO)

  16. Heat flows in piston compressors

    Lekic, U.; Kok, J.B.W.; van der Meer, T.H.; van Steenhoven, A.A.; Stoffels, G.G.M.

    2008-01-01

    Piston compressors are widely used in today's engineering applications. Among the most important applications is however the compression of thermal carrier gas in Rankine and Stirling refrigeration cycles. Fluids used in these cycles are commonly Ammonia and Helium. In order to improve the design

  17. Using helical compressors for coke gas condensation

    Privalov, V E; Rezunenko, Yu I; Lelyanov, N V; Zarnitzkii, G Eh; Gordienko, A A; Derebenko, I F; Venzhega, A G; Leonov, N P; Gorokhov, N N

    1982-08-01

    Coke oven gas compression is discussed. Presently used multilevel piston compressors are criticized. The paper recommends using helical machines which combine advantages of using volume condensing compressors and compact high-efficiency centrifugal machines. Two kinds of helical compressors are evaluated: dry and oil-filled; their productivities and coke oven gas chemical composition are analyzed. Experiments using helical compressors were undertaken at the Yasinovskii plant. Flowsheet of the installation is shown. Performance results are given in a table. For all operating conditions content of insolubles in oil compounds is found to be lower than the acceptable value (0.08%). Compressor productivity measurements with variable manifold pressure are evaluated. Figures obtained show that efficient condensation of raw coke oven gas is possible. Increasing oil-filled compressor productivity is recommended by decreasing amount of oil injected and simultaneously increasing rotation speed. The dry helical compressor with water seal is found to be most promising for raw coke oven gas condensation. (10 refs.)

  18. An exergy method for compressor performance analysis

    McGovern, J A; Harte, S [Trinity Coll., Dublin (Ireland)

    1995-07-01

    An exergy method for compressor performance analysis is presented. The purpose of this is to identify and quantify defects in the use of a compressor`s shaft power. This information can be used as the basis for compressor design improvements. The defects are attributed to friction, irreversible heat transfer, fluid throttling, and irreversible fluid mixing. They are described, on a common basis, as exergy destruction rates and their locations are identified. The method can be used with any type of positive displacement compressor. It is most readily applied where a detailed computer simulation program is available for the compressor. An analysis of an open reciprocating refrigeration compressor that used R12 refrigerant is given as an example. The results that are presented consist of graphs of the instantaneous rates of exergy destruction according to the mechanisms involved, a pie chart of the breakdown of the average shaft power wastage by mechanism, and a pie chart with a breakdown by location. (author)

  19. Meridional Considerations of the Centrifugal Compressor Development

    C. Xu

    2012-01-01

    Full Text Available Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

  20. Technical analysis of utilization suitability of various wind rotor’s types for compressor’s power driving

    Radim Rybár

    2005-03-01

    Full Text Available Conception is from the converting of wind energy, which flows across the wind turbine in mechanic work needed for compressor working. The wind motor one part of energy transform into mechanical work, part of energy is unused and part of energy of stead flow is transformed into eddy after wind rotor.The aim was rendering of technical analysis for equipment, which would use the wind with parameters for chosen area and whole unit would supply power in peak demand. Unit consists of wind turbine, which pushes compressor. Compressor pumps air into the compressed air storage. The air is used for power producing in time of peak demand.

  1. On the compressor ring for the JAERI neutron science project

    Yamane, Isao [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1997-11-01

    (1), As long as a 1.5 GeV-8 MW linear accelerator is constructed in the JAERI neutron science center, it is quite reasonable to construct a 5 MW compressor ring as a driver of a high intensity spallation neutron source to generate pulsed neutron beams. (2), Suppression of beam loss around the compressor ring to an acceptable level is the most crucial subject to be coped with in designing a MW-class compressor ring. This subject should be successfully cleared by carefully studying and designing the overall system of accelerator and tunnel. (3), The `PSR instability` was comprehensively discussed in the NSNS workshop held at Santa Fe in March, 1997, as a remaining problem of a high intensity proton compressor ring. People of Los Alamos attributed it to an e-p instability. But some questions like the cause that makes some part of protons leak away from a beam bunch to a bunch gap are yet left open. (4), A new scheme of two step H{sup 0} injection is proposed to remove defects of the conventional one of Los Alamos PSR. (author)

  2. Pulse compressor with aberration correction

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  3. Partially non-linear stimulation intensity-dependent effects of direct current stimulation on motor cortex excitability in humans.

    Batsikadze, G; Moliadze, V; Paulus, W; Kuo, M-F; Nitsche, M A

    2013-04-01

    Transcranial direct current stimulation (tDCS) of the human motor cortex at an intensity of 1 mA with an electrode size of 35 cm(2) has been shown to induce shifts of cortical excitability during and after stimulation. These shifts are polarity-specific with cathodal tDCS resulting in a decrease and anodal stimulation in an increase of cortical excitability. In clinical and cognitive studies, stronger stimulation intensities are used frequently, but their physiological effects on cortical excitability have not yet been explored. Therefore, here we aimed to explore the effects of 2 mA tDCS on cortical excitability. We applied 2 mA anodal or cathodal tDCS for 20 min on the left primary motor cortex of 14 healthy subjects. Cathodal tDCS at 1 mA and sham tDCS for 20 min was administered as control session in nine and eight healthy subjects, respectively. Motor cortical excitability was monitored by transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) from the right first dorsal interosseous muscle. Global corticospinal excitability was explored via single TMS pulse-elicited MEP amplitudes, and motor thresholds. Intracortical effects of stimulation were obtained by cortical silent period (CSP), short latency intracortical inhibition (SICI) and facilitation (ICF), and I wave facilitation. The above-mentioned protocols were recorded both before and immediately after tDCS in randomized order. Additionally, single-pulse MEPs, motor thresholds, SICI and ICF were recorded every 30 min up to 2 h after stimulation end, evening of the same day, next morning, next noon and next evening. Anodal as well as cathodal tDCS at 2 mA resulted in a significant increase of MEP amplitudes, whereas 1 mA cathodal tDCS decreased corticospinal excitability. A significant shift of SICI and ICF towards excitability enhancement after both 2 mA cathodal and anodal tDCS was observed. At 1 mA, cathodal tDCS reduced single-pulse TMS-elicited MEP amplitudes and shifted SICI

  4. Compressors. These little things that improve the operation of air conditioners. Danfoss-Turbocor: magnetic bearings for a centrifugal compressor. Copeland: the group stresses on the Digital power variation; Dossier compresseurs. Ces petits plus qui ameliorent le fonctionnement des climatiseurs. Danfoss-Turbocor: des paliers magnetiques pour un compresseur centrifuge. Copeland: le groupe met l'accent sur la variation de puissance Digital

    Nicolas, J.

    2005-09-01

    This dossier about compressors for air conditioners comprises three articles dealing with: the improvements made by manufacturers of air-conditioning systems to increase the coefficient of performance and the lifetime of compressors, to reduce the refrigerant leaks and to reduce the power consumption; the electromagnetic bearings, the speed variation and the double stage compression used in the Danfoss-Turbocor centrifugal compressor; and the 'Digital' mechanical power variation system used by Copeland which does not change the motor velocity nor the operation limits of the compressor. (J.S.)

  5. A Model for Analyzing a Five-Phase Fractional-Slot Permanent Magnet Tubular Linear Motor with Modified Winding Function Approach

    Bo Zhang

    2016-01-01

    Full Text Available This paper presents a model for analyzing a five-phase fractional-slot permanent magnet tubular linear motor (FSPMTLM with the modified winding function approach (MWFA. MWFA is a fast modeling method and it gives deep insight into the calculations of the following parameters: air-gap magnetic field, inductances, flux linkages, and detent force, which are essential in modeling the motor. First, using a magnetic circuit model, the air-gap magnetic density is computed from stator magnetomotive force (MMF, flux barrier, and mover geometry. Second, the inductances, flux linkages, and detent force are analytically calculated using modified winding function and the air-gap magnetic density. Finally, a model has been established with the five-phase Park transformation and simulated. The calculations of detent force reveal that the end-effect force is the main component of the detent force. This is also proven by finite element analysis on the motor. The accuracy of the model is validated by comparing with the results obtained using semianalytical method (SAM and measurements to analyze the motor’s transient characteristics. In addition, the proposed method requires less computation time.

  6. Torque Ripple Reduction of a Novel Modular Arc-Linear Flux-Switching Permanent-Magnet Motor with Rotor Step Skewing

    Xiangdong Liu

    2016-05-01

    Full Text Available A novel modular arc-linear flux-switching permanent-magnet motor (MAL-FSPM used for scanning system instead of reduction gearboxes and kinematic mechanisms is proposed and researched in this paper by the finite element method (FEM. The MAL-FSPM combines characteristics of flux-switching permanent-magnet motor and linear motor and can realize the direct driving and limited angular movement. Structure and operation principle of the MAL-FSPM are analyzed. Cogging torque model of the MAL-FSPM is established. The characteristics of cogging torque and torque ripple are investigated for: (1 distance (dend between left end of rotor and left end of stator is more than two rotor tooth pitch (τp; and (2 dend is less than two rotor tooth pitch. Cogging torque is an important component of torque ripple and the period ratio of the cogging torque to the back electromotive force (EMF equals one for the MAL-FSPM before optimization. In order to reduce the torque ripple as much as possible and affect the back EMF as little as possible, influence of period ratio of cogging torque to back EMF on rotor step skewing is investigated. Rotor tooth width and stator slot open width are optimized to increase the period ratio of cogging torque to back EMF. After the optimization, torque ripple is decreased by 79.8% for dend > τp and torque ripple is decreased by 49.7% for dend < τp. Finally, 3D FEM model is established to verify the 2D results.

  7. Flow Range of Centrifugal Compressor Being Extended

    Skoch, Gary J.

    2001-01-01

    General Aviation will benefit from turbine engines that are both fuel-efficient and reliable. Current engines fall short of their potential to achieve these attributes. The reason is compressor surge, which is a flow stability problem that develops when the compressor is subjected to conditions that are outside of its operating range. Compressor surge can occur when fuel flow to the engine is increased, temporarily back pressuring the compressor and pushing it past its stability limit, or when the compressor is subjected to inlet flow-field distortions that may occur during takeoff and landing. Compressor surge can result in the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. Unfortunately, the most efficient operating line for the compressor is usually closer to its stability limit line than it is to the line that provides an adequate margin of safety. A wider stable flow range will permit operation along the most efficient operating line of the compressor, improving the specific fuel consumption of the engine and reducing emissions. The NASA Glenn Research Center is working to extend the stable flow range of the compressor. Significant extension has been achieved in axial compressors by injecting air upstream of the compressor blade rows. Recently, the technique was successfully applied to a 4:1 pressure ratio centrifugal compressor by injecting streams of air into the diffuser. Both steady and controlled unsteady injection were used to inject air through the diffuser shroud surface and extend the range. Future work will evaluate the effect of air injection through the diffuser hub surface and diffuser vanes with the goal of maximizing the range extension while minimizing the amount of injected air that is required.

  8. Centrifugal and axial compressor control

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  9. Magnetic power piston fluid compressor

    Gasser, Max G. (Inventor)

    1994-01-01

    A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

  10. All-optical fiber compressor

    Ivanov, Luben M.

    2015-01-01

    A simple all-optical fiber compressor, based on an idea of dispersion management using a fiber of positive dispersion in the first part and of negative dispersion in the second one at the working wavelength, is investigated. The method allows a combination of the advantages of the classic fiber-grating and of the multisoliton compression. It is possible to improve substantially the quality of the compressed pulse compared to the multisoliton compression. The compression factor could be increased up to 2-2.5 times when the fraction of the input pulse energy appearing within the compressed pulse enhances more than 2 times. Thus, the peak power of the compressed pulse is able to increase about 5 times and the quality of the obtained pulses should be comparable with those obtained by the fiber-grating compressor

  11. Fault location repair, rewinding and commissioning of 3.3 kV, 850 kW synchronous motor (Paper No. 5.9)

    Subramanian, A.R.; Palani, R.A.A.

    1992-01-01

    The 20K41 compressor in Heavy Water Plant, Tuticorin is compressing medium pressure synthesis gas to high pressure. The compressor is driven by synchronous motor of capacity 850 kW at 3.3 kV. The synchronous motor had been selected for operating a reciprocating compressor because of the compressor's low speed, higher capacity, vibration level etc. Partially it helps for power factor improvement and constant compression of the gas. This paper describes the details of the motor, stator and rotor, method of repair and rewinding of synchronous motor. (author)

  12. Modeling of flexible reciprocating compressor considering the crosshead subsidence

    Xue, Xiaogang; Liu, Shulin; Sun, Xin

    2018-01-01

    Crank-slider mechanisms are important parts of heavy duty machines, including reciprocating compressors, combustion motors. This paper targets on the dynamic response of the crosshead in a reciprocating compressor, taking into consideration the crosshead deviation from the original level. The traditional model of the compressor is usually a slider-mechanism system without considering the deflection of the crosshead, thus neglecting the influence of the piston rod, which has some flexible features. In this paper, a rigid-flexible model of slider-crank is described theoretically, using the commercial software MATLAB, where the crank, connecting rod and crosshead are treated as rigid bodies, while the piston rod connected to the crosshead is considered as a flexible body. The dynamic response of the mechanism with the crosshead subsidence is discussed detailedly in this paper. After calculated theoretically, the MATLAB simulation showed that the dynamic response of the crosshead will be greatly influenced if the crosshead subsided from the original level. Also, the influence of the crosshead subsidence was also investigated, and some extra vibration of the crosshead arises.

  13. Axial-Centrifugal Compressor Program

    1975-10-01

    Assembly . .. . .... ..... 33 5 Tie Bolt...... .. .. .. .. . *.. .. .. .. .. .. ... 34 6 Axial Compressor Rotor Assembly Runouts . . .. . 34 7 CCV Blow...1.796 Impeller Slip Factor ’Ce2/U 2 ) .91 Impeller Wheel Speed ft/sec 1992.2 Impellet ’.ip Radius in. 3.780 Blade Tip Metal Angle- deg 0 Numbec of Blades...test item to the next Phase V component test. The test vehicle final balance levels and rotor runouts were normal at teardown, and no rubsI were

  14. Feasibility study of a periodic arc compressor in the presence of coherent synchrotron radiation

    Di Mitri, S.

    2016-01-01

    The advent of short electron bunches in high brightness linear accelerators has raised the awareness of the accelerator community to the degradation of the beam transverse emittance by coherent synchrotron radiation (CSR) emitted in magnetic bunch length compressors, transfer lines and turnaround arcs. Beam optics control has been proposed to mitigate that CSR effect. In this article, we enlarge on the existing literature by reviewing the validity of the linear optics approach in a periodic, achromatic arc compressor. We then study the dependence of the CSR-perturbed emittance to beam optics, mean energy, and bunch charge. The analytical findings are compared with particle tracking results. Practical considerations on CSR-induced energy loss and nonlinear particle dynamics are included. As a result, we identify the range of parameters that allows feasibility of an arc compressor for driving, for example, a free electron laser or a linear collider.

  15. Feasibility study of a periodic arc compressor in the presence of coherent synchrotron radiation

    Di Mitri, S.

    2016-01-11

    The advent of short electron bunches in high brightness linear accelerators has raised the awareness of the accelerator community to the degradation of the beam transverse emittance by coherent synchrotron radiation (CSR) emitted in magnetic bunch length compressors, transfer lines and turnaround arcs. Beam optics control has been proposed to mitigate that CSR effect. In this article, we enlarge on the existing literature by reviewing the validity of the linear optics approach in a periodic, achromatic arc compressor. We then study the dependence of the CSR-perturbed emittance to beam optics, mean energy, and bunch charge. The analytical findings are compared with particle tracking results. Practical considerations on CSR-induced energy loss and nonlinear particle dynamics are included. As a result, we identify the range of parameters that allows feasibility of an arc compressor for driving, for example, a free electron laser or a linear collider.

  16. Dense-plasma research using ballistic compressors

    Hess, H.

    1986-01-01

    An introduction is given to research on dense (or nonideal) plasmas which can be generated to advantage by ballistic compressors. Some properties of ballistic compressors are discussed especially in comparison with shock tubes. A short review is given on the history of these devices for high-pressure plasma generation. The present state of the art is reported including research on the two ZIE (Central Institute for Electron Physics) ballistic compressors. (author)

  17. Numerical simulation of radial compressor stage

    Syka, T.; Luňáček, O.

    2013-04-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  18. Numerical simulation of radial compressor stage

    Luňáček O.; Syka T.

    2013-01-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  19. Numerical simulation of radial compressor stage

    Luňáček O.

    2013-04-01

    Full Text Available Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  20. Design features of fans, blowers, and compressors

    Cheremisinoff, N. P.; Cheremisinoff, P. N.

    Fan engineering and compression machines are discussed. Basic aspects of fan performance and design are reviewed, and the design and performance characteristics of radial-flow fans, axial-flow fans, and controllable pitch fans are examined in detail. Air-conditioning systems are discussed, and noise, vibration, and mechanical considerations in fans are extensively examined. The thermodynamic principles governing compression machines are reviewed, and piston compressors, rotary compressors, blowers, and centrifugal compressors are discussed.

  1. Detector for flow abnormalities in gaseous diffusion plant compressors

    Smith, S.F.; Castleberry, K.N.

    1998-06-16

    A detector detects a flow abnormality in a plant compressor which outputs a motor current signal. The detector includes a demodulator/lowpass filter demodulating and filtering the motor current signal producing a demodulated signal, and first, second, third and fourth bandpass filters connected to the demodulator/lowpass filter, and filtering the demodulated signal in accordance with first, second, third and fourth bandpass frequencies generating first, second, third and fourth filtered signals having first, second, third and fourth amplitudes. The detector also includes first, second, third and fourth amplitude detectors connected to the first, second, third and fourth bandpass filters respectively, and detecting the first, second, third and fourth amplitudes, and first and second adders connected to the first and fourth amplitude detectors and the second and third amplitude detectors respectively, and adding the first and fourth amplitudes and the second and third amplitudes respectively generating first and second added signals. Finally, the detector includes a comparator, connected to the first and second adders, and comparing the first and second added signals and detecting the abnormal condition in the plant compressor when the second added signal exceeds the first added signal by a predetermined value. 6 figs.

  2. 30 CFR 75.344 - Compressors.

    2010-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.344 Compressors. (a) Except compressors that are...), shall be equipped with a heat activated fire suppression system meeting the requirements of 75.1107-3...

  3. 40 CFR 63.1031 - Compressors standards.

    2010-07-01

    ... the compressor drive shaft seal to a process or a fuel gas system or to a closed vent system that... specified in the referencing subpart. (b) Seal system standard. Each compressor shall be equipped with a seal system that includes a barrier fluid system and that prevents leakage of process fluid to the...

  4. Air compressor efficiency in a Vietnamese enterprise

    Yang, Ming [3E and T International, Suite 1506, Building No. 10, Luo Ma Shi Street, Xuan Wu District, Beijing 100052 (China)

    2009-06-15

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%. (author)

  5. Air compressor efficiency in a Vietnamese enterprise

    Yang Ming [3E and T International, Suite 1506, Building No. 10, Luo Ma Shi Street, Xuan Wu District, Beijing 100052 (China)], E-mail: ming.yang7@gmail.com

    2009-06-15

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%.

  6. Air compressor efficiency in a Vietnamese enterprise

    Yang Ming

    2009-01-01

    Compressed air systems in a Vietnamese footwear manufacturing enterprise consume about 10% of enterprise's total electric power supply. Energy efficiency of these air compressor systems, either equipped with new and efficient compressors or old and inefficient ones, can only reach between 5% and 10%. In other words, regardless whatever air compressors were installed, energy loss from the compressor systems was over 80%. This study discovered that energy loss was due to non-optimized operations of the air compressor systems and air leakages. The objectives of the paper are to uncover energy saving potential in Vietnamese air compressor systems, demonstrate methodologies used in the auditing and assessment, share auditing and assessment results, and serve a guide on how to analyze energy efficiency in a compressed air system. This paper concludes that energy efficiency investment in air compressor systems in the Vietnamese enterprise could be extremely cost-effective. If the enterprise invests USD 84,000 in the air compressors to improve efficiency performance, the investment capital will be recovered in about six months. The net present value of the investment will be about USD 864,000 at a discount rate of 12%.

  7. A high pressure centrifugal oxygen compressor

    Larsen, L.P.

    1986-01-01

    The application of a centrifugal compressor train to 5860 kPa(g) (850 psig) for a coal gasification plant is discussed. Special considerations in the application, installation, and operation of the equipment are presented. Discussion includes such topics as compressor controls, machinery protection, noise, personnel safety, and operation of the equipment

  8. High frequency dynamics in centrifugal compressors

    Twerda, A.; Meulendijks, D.; Smeulers, J.P.M.; Handel, R. van den; Lier, L.J. van

    2008-01-01

    Problems with centrifugal compressors relating to high frequency, i.e. Blade passing frequency (BPF) are increasing. Pulsations and vibrations generated in centrifugal compressors can lead to nuisance, due to strong tonal noise, and even breakdown. In several cases the root cause of a failure or a

  9. Modeling and control of compressor flow instabilities

    Willems, F.P.T.; Jager, de A.G.

    1999-01-01

    Compressors are widely used for the pressurization of fluids. Applications involve air compression for use in aircraft engines and pressurization and transportation of gas in the process and chemical industries. The article focuses on two commonly used types of continuous flow compressors: the axial

  10. Fast reversible wavelet image compressor

    Kim, HyungJun; Li, Ching-Chung

    1996-10-01

    We present a unified image compressor with spline biorthogonal wavelets and dyadic rational filter coefficients which gives high computational speed and excellent compression performance. Convolutions with these filters can be preformed by using only arithmetic shifting and addition operations. Wavelet coefficients can be encoded with an arithmetic coder which also uses arithmetic shifting and addition operations. Therefore, from the beginning to the end, the while encoding/decoding process can be done within a short period of time. The proposed method naturally extends form the lossless compression to the lossy but high compression range and can be easily adapted to the progressive reconstruction.

  11. Refrigeration system having standing wave compressor

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  12. Design and Parametric Study of the Magnetic Sensor for Position Detection in Linear Motor Based on Nonlinear Parametric model order reduction.

    Paul, Sarbajit; Chang, Junghwan

    2017-07-01

    This paper presents a design approach for a magnetic sensor module to detect mover position using the proper orthogonal decomposition-dynamic mode decomposition (POD-DMD)-based nonlinear parametric model order reduction (PMOR). The parameterization of the sensor module is achieved by using the multipolar moment matching method. Several geometric variables of the sensor module are considered while developing the parametric study. The operation of the sensor module is based on the principle of the airgap flux density distribution detection by the Hall Effect IC. Therefore, the design objective is to achieve a peak flux density (PFD) greater than 0.1 T and total harmonic distortion (THD) less than 3%. To fulfill the constraint conditions, the specifications for the sensor module is achieved by using POD-DMD based reduced model. The POD-DMD based reduced model provides a platform to analyze the high number of design models very fast, with less computational burden. Finally, with the final specifications, the experimental prototype is designed and tested. Two different modes, 90° and 120° modes respectively are used to obtain the position information of the linear motor mover. The position information thus obtained are compared with that of the linear scale data, used as a reference signal. The position information obtained using the 120° mode has a standard deviation of 0.10 mm from the reference linear scale signal, whereas the 90° mode position signal shows a deviation of 0.23 mm from the reference. The deviation in the output arises due to the mechanical tolerances introduced into the specification during the manufacturing process. This provides a scope for coupling the reliability based design optimization in the design process as a future extension.

  13. 33 CFR 154.826 - Vapor compressors and blowers.

    2010-07-01

    ...) Excessive shaft bearing temperature. (d) If a centrifugal compressor, fan, or lobe blower handles vapor in... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor compressors and blowers....826 Vapor compressors and blowers. (a) Each inlet and outlet to a compressor or blower which handles...

  14. The China Motor Systems Energy Conservation Program: A major national initiative to reduce motor system energy use in China

    Nadel, Steven; Wang, Wanxing; Liu, Peter; McKane, Aimee T.

    2001-05-31

    Electric motor systems are widely used in China to power fans, pumps, blowers, air compressors, refrigeration compressors, conveyers, machinery, and many other types of equipment. Overall, electric motor systems consume more than 600 billion kWh annually, accounting for more than 50 percent of China's electricity use. There are large opportunities to improve the efficiency of motor systems. Electric motors in China are approximately 2-4 percent less efficient on average than motors in the U.S. and Canada. Fans and pumps in China are approximately 3-5 percent less efficient than in developed countries. Even more importantly, motors, fans, pumps, air compressors and other motor-driven equipment are frequently applied with little attention to system efficiency. More optimized design, including appropriate sizing and use of speed control strategies, can reduce energy use by 20 percent or more in many applications. Unfortunately, few Chinese enterprises use or even know about these energy-saving practices. Opportunities for motor system improvements are probably greater in China than in the U.S. In order to begin capturing these savings, China is establishing a China Motor Systems Energy Conservation Program. Elements of this program include work to develop minimum efficiency standards for motors, a voluntary ''green motor'' labeling program for high-efficiency motors, efforts to develop and promote motor system management guidelines, and a training, technical assistance and financing program to promote optimization of key motor systems.

  15. Comparison of Thrust Characteristics in Pencil Sized Cylinder-type Linear Motors with Different Magnet Arrays(Asia-Pacific Symposium on Applied Electromagnetics and Mechanics (APSAEM08))

    K., Nakaiwa; A., Yamada; K., Tashiro; H., Wakiwaka; Tamagawa-Seiki Co., Ltd; Shinshu University; Shinshu University; Shinshu University

    2009-01-01

    From a strong demand on the miniaturization of a chip mounter or a semiconductor device, the thrust improvement considering the magnets arrangement is studied. We accept a core stator with a Halbach type magnet array for a current linear motor. The thrust characteristics are compared with two kinds of mover, a NS magnet array and a Halbach magnet array.

  16. Investigation of axial positioning for flexural compressors

    Riggle, Peter

    1991-01-01

    The testing of the research compressor is presented. The research compressor was assembled and disassembled in order to show the consistency in which the piston and rod could be aligned with a .0004 inch radial gap around the piston. A full set of tests was completed for the first assembly, which is referred to as assembly no. 1. The compressor was disassembled and assembled a second time (assembly no. 2). Assembly no. 2 was only tested statically due to the time constraint. Results are discussed.

  17. Compressor Has No Moving Macroscopic Parts

    Gasser, Max

    1995-01-01

    Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

  18. Compressor Part I: Measurement and Design Modeling

    Thomas W. Bein

    1999-01-01

    method used to design the 125-ton compressor is first reviewed and some related performance curves are predicted based on a quasi-3D method. In addition to an overall performance measurement, a series of instruments were installed on the compressor to identify where the measured performance differs from the predicted performance. The measurement techniques for providing the diagnostic flow parameters are also described briefly. Part II of this paper provides predictions of flow details in the areas of the compressor where there were differences between the measured and predicted performance.

  19. Compressor ported shroud for foil bearing cooling

    Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  20. Failure of the CAPS compressor(s). Final unusual occurrence report

    Kuechle, J.D.

    1981-01-01

    Acceptance testing of the CAPS compressors (4) was in progress which required periodic running of these units. Some vibration problems had occurred which required compressor shutdown for visual inspection and repair. During the performance of this visual inspection, it was decided to remove the crank case covers and to inspect the lower section of the cylinder liners for wear. The inspection revealed excessive scoring of the vertical cylinder liners on two of the four compressors that were opened. Acceptance testing of the CAPS compressors was suspended, pending further evaluation and repair

  1. Design, fabrication, commissioning, and testing of a 250 g/s, 2-K helium cold compressor system

    V. Ganni; D. M. Arenius; B. S. Bevins; W. C. Chronis; J. D. Creel; J. D. Wilson Jr.

    2002-01-01

    In June 1999 the Thomas Jefferson National Accelerator Facility (TJNAF) Cryogenic Systems Group had completed the design, fabrication, and commissioning of a cold compressor system capable of pumping 250 g/s of 2-K helium vapor to a pressure above 1 bar. The 2-K cold box consists of five stages of centrifugal variable speed compressors with LN2 cooled drive motors and magnetic bearings, a plate fin heat exchanger, and an LN2 shield system. The new 2-K cold box (referred to as the SCN) was built as a redundant system to an existing four stage cold compressor SCM cold box that was commissioned in May 1994. The SCN has been in continuous service supporting the facility experiments since commissioning. This system has achieved a significant improvement in the total 2-K refrigeration system capacity and stability and has substantially increased the operating envelope both in cold compressor flow and operating pressure range. This paper describes the cold box configuration and the experience s in the design, fabrication, commissioning and performance evaluation. The capacity of the system for various operating pressures (0.040 to 0.025 bar at the load corresponding to a total compressor pressure ratio of 28 to 54) is presented. An effort is made to characterize the components and their operating data over the tested range. This includes the return side pressure drop in the distribution system, the heat exchanger, and the cold compressor characteristics. The system design parameters and their effects on performance are outlined

  2. Multi-Objective Optimization of Moving-magnet Linear Oscillatory Motor Using Response Surface Methodology with Quantum-Behaved PSO Operator

    Lei, Meizhen; Wang, Liqiang

    2018-01-01

    To reduce the difficulty of manufacturing and increase the magnetic thrust density, a moving-magnet linear oscillatory motor (MMLOM) without inner-stators was Proposed. To get the optimal design of maximum electromagnetic thrust with minimal permanent magnetic material, firstly, the 3D finite element analysis (FEA) model of the MMLOM was built and verified by comparison with prototype experiment result. Then the influence of design parameters of permanent magnet (PM) on the electromagnetic thrust was systematically analyzed by the 3D FEA to get the design parameters. Secondly, response surface methodology (RSM) was employed to build the response surface model of the new MMLOM, which can obtain an analytical model of the PM volume and thrust. Then a multi-objective optimization methods for design parameters of PM, using response surface methodology (RSM) with a quantum-behaved PSO (QPSO) operator, was proposed. Then the way to choose the best design parameters of PM among the multi-objective optimization solution sets was proposed. Then the 3D FEA of the optimal design candidates was compared. The comparison results showed that the proposed method can obtain the best combination of the geometric parameters of reducing the PM volume and increasing the thrust.

  3. Optimum Performances for Non-Linear Finite Elements Model of 8/6 Switched Reluctance Motor Based on Intelligent Routing Algorithms

    Chouaib Labiod

    2017-01-01

    Full Text Available This paper presents torque ripple reduction with speed control of 8/6 Switched Reluctance Motor (SRM by the determination of the optimal parameters of the turn on, turn off angles Theta_(on, Theta_(off, and the supply voltage using Particle Swarm Optimization (PSO algorithm and steady state Genetic Algorithm (ssGA. With SRM model, there is difficulty in the control relapsed into highly non-linear static characteristics. For this, the Finite Elements Method (FEM has been used because it is a powerful tool to get a model closer to reality. The mechanism used in this kind of machine control consists of a speed controller in order to determine current reference which must be produced to get the desired speed, hence, hysteresis controller is used to compare current reference with current measured up to achieve switching signals needed in the inverter. Depending on this control, the intelligent routing algorithms get the fitness equation from torque ripple and speed response so as to give the optimal parameters for better results. Obtained results from the proposed strategy based on metaheuristic methods are compared with the basic case without considering the adjustment of specific parameters. Optimized results found clearly confirmed the ability and the efficiency of the proposed strategy based on metaheuristic methods in improving the performances of the SRM control considering different torque loads.

  4. Scanning slit for HIE-ISOLDE: vibrations test (linear motion actuator from UHV design, MAXON brushless motor, speed = 10 mm/s)

    Bravin, E; Sosa, A

    2014-01-01

    This report summarizes the results of a series of tests performed on the prototype HIE-ISOLDE diagnostic box (HIE-DB) regarding the vibrations and drifts in the transverse position of the scanning blade while moving in and out of beam path in the HIE-ISOLDE short box prototype. To monitor the transverse position of the blade, a series of 0.1 mm diameter holes were drilled on it and their positions were tracked with an optical system. The linear motion actuator was acquired from UHV design (model LSM38-150-SS), and it was adapted to be driven by a brushless EC motor from MAXON. The speed of the scanning blade during the tests was 10 mm/s. The transverse movement of the slit in the direction perpendicular to the movement was lower than 40 m, and is dominated by the displacement of the contact point of the applied force on the lead-screw. An offset on the slit position was observed while changing the direction of movement of the blade, its amplitude being of the order of 30 m. The amplitudes of the displacements...

  5. 40 CFR 65.112 - Standards: Compressors.

    2010-07-01

    ... the compressor stuffing box pressure at all times (except during periods of start-up, shutdown, or... process stream. (c) Barrier fluid system. The barrier fluid shall not be in light liquid service. Each...

  6. 40 CFR 265.1053 - Standards: Compressors.

    2010-07-01

    ...) Operated with the barrier fluid at a pressure that is at all times greater than the compressor stuffing box... purges the barrier fluid into a hazardous waste stream with no detectable emissions to atmosphere. (c...

  7. 40 CFR 264.1053 - Standards: Compressors.

    2010-07-01

    ... with the barrier fluid at a pressure that is at all times greater than the compressor stuffing box... purges the barrier fluid into a hazardous waste stream with no detectable emissions to atmosphere. (c...

  8. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2017-01-01

    A centrifugal compressor research effort conducted by United Technologies Research Center under NASA Research Announcement NNC08CB03C is documented. The objectives were to identify key technical barriers to advancing the aerodynamic performance of high-efficiency, high work factor, compact centrifugal compressor aft-stages for turboshaft engines; to acquire measurements needed to overcome the technical barriers and inform future designs; to design, fabricate, and test a new research compressor in which to acquire the requisite flow field data. A new High-Efficiency Centrifugal Compressor stage -- splittered impeller, splittered diffuser, 90 degree bend, and exit guide vanes -- with aerodynamically aggressive performance and configuration (compactness) goals were designed, fabricated, and subquently tested at the NASA Glenn Research Center.

  9. Turbofan compressor dynamics during afterburner transients

    Kurkov, A. P.

    1976-01-01

    The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

  10. Experimental Study for Reduction of Noises and Vibrations in Hermetic Type Compressor

    Sano, Kiyoshi; Kawahara, Sadao; Akazawa, Teruyuki; Ishii, Noriaki

    A brushless DC motor with a permanent magnet rotor has been adopted for a scroll compressor for domestic-use air-conditioners because of a demand for compressor high efficiency. A waveform of the driving voltage in the inverter power supply unit is chopped by the PWM signal. Its duty ratio is increased/decreased to control the DC voltage in order to provide a wide range of rotation frequencies for the compressor. The driving voltage includes the carrier frequency and its harmonic components, which produce an electro-magnetic force in the moter, resulting in high electro-magnetic noise. In the present report, the author clarifies the relationships between the noise and the waveform of driving voltage and frequency response function of the motor. A method to improve the frequency response function by changing the stator shape in order to reduce electro-magnetic noise is presented. Subsequently, the influence on electro-magnetic noise from the waveform of driving voltage is examined. Furthermore, the electro-magnetic noises during inverter driving of an induction motor are presented.

  11. Linear Collider Working Group reports from Snowmass '88

    Ruth, R.D.

    1989-03-01

    This report contains a summary of the Linear Collider Working Group. Papers on the following topics are discussed: parameters; damping ring; bunch compressor; linac; final focus; and multibunch effects

  12. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  13. A one kPa centrifugal cold compressor for the 1.8 K helium refrigeration system of LHC

    Saji, N; Yoshinaga, S; Itoh, K; Nogaku, T; Bézaguet, Alain-Arthur; Casas-Cubillos, J; Lebrun, P; Tavian, L

    1998-01-01

    CERN placed an order for a cold compressor prototype (CCP) with IHI for the LHC project. The CCP is supported by the oil-free magnetic bearings, driven by an induction motor. The compressor has the characteristics of high efficiency and wide operation range, thanks to the optimum design for the impeller and diffuser. The result of the performance tests at CERN showed that static heat in-leaks could be controlled at approx. 7.3 W, and an adiabatic efficiency is 75at a nominal flow of 18 g's with suction temperature of 4.4 K and suction pressure of 1 kPa. (4 refs).

  14. Piezoelectric Motors, an Overview

    Karl Spanner; Burhanettin Koc

    2016-01-01

    Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ult...

  15. Thermal performance analysis of reciprocating compressor with stepless capacity control system

    Bin, Tang; Yuanyang, Zhao; Liansheng, Li; Guangbin, Liu; Le, Wang; Qichao, Yang; Haiping, Xu; Feng, Zhu; Wenhui, Meng

    2013-01-01

    On the basic principle of stepless capacity control system for large reciprocating compressor, the thermal cycle was analyzed. The equations for the process of suction, reverse flow, compression, discharge and expansion of clearance gas were established. According to these equations, p–V diagrams at various situations were simulated. An experimental platform was setup and the compressor with designed stepless capacity control system run well. The experimental results show that the capacity of compressor can be regulated steplessly, and the motor power is reduced proportionally with respect to the reduction of capacity. During the suction process, both the flow resistance of valve and the pressure fluctuation in cylinder can be reduced by opening the suction valves with the actuators. The simulated and experimental results showed good coincidence. The clearance volume and valve clearance Mach number had a negative influence on the thermal performance of compressor with stepless capacity control system. -- Highlights: ► Flow resistance of valve can be reduced and pressure fluctuation can be reduced. ► Equivalent Mach number of reverse flow is much higher than that of suction process. ► Response of stepless capacity control system is important for regulation accuracy. ► Clearance and valve clearance Mach number have influence on thermal performance

  16. Experimental Investigation of Centrifugal Compressor Stabilization Techniques

    Skoch, Gary J.

    2003-01-01

    Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

  17. Identifying lubricant options for compressor bearing designs

    Karnaz, J.; Seeton, C.; Dixon, L.

    2017-08-01

    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  18. Miniature linear cooler development

    Pruitt, G.R.

    1993-01-01

    An overview is presented of the status of a family of miniature linear coolers currently under development by Hughes Aircraft Co. for use in hand held, volume limited or power limited infrared applications. These coolers, representing the latest additions to the Hughes family of TOP trademark [twin-opposed piston] linear coolers, have been fabricated and tested in three different configurations. Each configuration is designed to utilize a common compressor assembly resulting in reduced manufacturing costs. The baseline compressor has been integrated with two different expander configurations and has been operated with two different levels of input power. These various configuration combinations offer a wide range of performance and interface characteristics which may be tailored to applications requiring limited power and size without significantly compromising cooler capacity or cooldown characteristics. Key cooler characteristics and test data are summarized for three combinations of cooler configurations which are representative of the versatility of this linear cooler design. Configurations reviewed include the shortened coldfinger [1.50 to 1.75 inches long], limited input power [less than 17 Watts] for low power availability applications; the shortened coldfinger with higher input power for lightweight, higher performance applications; and coldfingers compatible with DoD 0.4 Watt Common Module coolers for wider range retrofit capability. Typical weight of these miniature linear coolers is less than 500 grams for the compressor, expander and interconnecting transfer line. Cooling capacity at 80K at room ambient conditions ranges from 400 mW to greater than 550 mW. Steady state power requirements for maintaining a heat load of 150 mW at 80K has been shown to be less than 8 Watts. Ongoing reliability growth testing is summarized including a review of the latest test article results

  19. Centrifugal Compressor Unit-based Heat Energy Recovery at Compressor Stations

    V. S. Shadrin

    2016-01-01

    Full Text Available About 95% of the electricity consumed by air compressor stations around the world, is transformed into thermal energy, which is making its considerable contribution to global warming. The present article dwells on the re-use (recovery of energy expended for air compression.The article presents the energy analysis of the process of compressing air from the point of view of compressor drive energy conversion into heat energy. The temperature level of excess heat energy has been estimated in terms of a potential to find the ways of recovery of generated heat. It is shown that the temperature level formed by thermal energy depends on the degree of air compression and the number of stages of the compressor.Analysis of technical characteristics of modern equipment from leading manufacturers, as well as projects of the latest air compressor stations have shown that there are two directions for the recovery of heat energy arising from the air compression: Resolving technological problems of compressor units. The use of the excess heat generation to meet the technology objectives of the enterprise. This article examines the schematic diagrams of compressor units to implement the idea of heat recovery compression to solve technological problems: Heating of the air in the suction line during operation of the compressor station in winter conditions. Using compression heat to regenerate the adsorbent in the dryer of compressed air.The article gives an equity assessment of considered solutions in the total amount of heat energy of compressor station. Presented in the present work, the analysis aims to outline the main vectors of technological solutions that reduce negative impacts of heat generation of compressor stations on the environment and creating the potential for reuse of energy, i.e. its recovery.

  20. Kinetics of a gas adsorption compressor

    Chan, C.K.; Elleman, D.D.; Tward, E.

    1984-01-01

    This chapter uses a two-phase model to analyze the transients of a gas adsorption compressor. The modeling of the adsorption process is based on complete thermal and mechanical equilibrium between the gaseous phase and the adsorbed gas phase. The theories and techniques that have been developed for a two-phase system are used to predict the pressure, the temperature and the mass flow transients in a gas sorption compressor. The analytical solutions are then compared with the performance of a laboratory gas adsorption compressor. A computer code was written to solve the governing equations, using a standard forward marching predictor-corrector method. It is found that while the analytical model overpredicts the pressure and the temperature transient, it predicts the general trend of the transient profile and the existence of the turning point

  1. Compressor airfoil tip clearance optimization system

    Little, David A.; Pu, Zhengxiang

    2015-08-18

    A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

  2. Control de velocidad del motor de indución empleando linealización por realimentación de estados Speed control of induction motor using state feedback linearization

    Eduardo Giraldo Suárez; Santiago Sánchez Acevedo

    2009-01-01

    Este documento presenta la aplicación de la técnica de control no lineal clásica llamada linealización por realimentación de variables de estado. Se hace una aplicación en el motor de inducción, la variable a controlar es la velocidad del eje del motor, el sistema emplea el esquema de control vectorial para máquinas de corriente alterna desarrollado en las últimas décadas; este método es análogo a la técnica de control del motor de corriente directa. El modelo del motor de inducción se descri...

  3. Cold Climate Heat Pumps Using Tandem Compressors

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  4. Active compressor engine silencer reduces exhaust noise

    Denenberg, J.N.; Miller, S.K.; Jay, M.A.

    1994-01-01

    An active industrial silencer on a compressor engine at a Tenneco Gas station has reduced low-frequency 'rumbling' noise by 8 dB during trials while lowering backpressure about 90$. This 8 dB reduction of the piston firing frequency corresponds to a more than 80% decrease in emitted acoustic power. The silencing unit, installed on one of six engines at the station near Eden, N.Y., continues in operation. Based on the results, the manufacturer is identifying additional compressor sites for further tests. This paper reviews this project

  5. Centrifugal compressor design options for small turbochargers

    Rodgers, C. [ITC, San Diego (United States)

    1998-07-01

    Evolutionary development of the small turbocharger centrifugal compressor over the past four decades has resulted in a finely honed turbomachinery component satisfying both thermodynamic and economic constraints. At this penultimate stage of development an appraisal was considered timely of the remaining design options that exist to enhance the performance characteristics and cost reduction features. This paper presents the results of an analytical study of various small centrifugal compressor design options, assessed in merit of both aerodynamic and manufacturing cost attributes, together with recommendations for future research avenues. (author)

  6. Low-temperature centrifugal helium compressor

    Kawada, M.; Togo, S.; Akiyama, Y.; Wada, R.

    1974-01-01

    A centrifugal helium compressor with gas bearings, which can be operated at the temperature of liquid nitrogen, has been investigated. This compressor has the advantages that the compression ratio should be higher than the room temperature operation and that the contamination of helium could be eliminated. The outer diameter of the rotor is 112 mm. The experimental result for helium gas at low temperature shows a flow rate of 47 g/s and a compression ratio of 1.2 when the inlet pressure was 1 ata and the rotational speed 550 rev/s. The investigation is now focused on obtaining a compression ratio of 1.5. (author)

  7. Tests of cold helium compressors at Fermilab

    Peterson, T.J.; Fuerst, J.D.

    1988-01-01

    Fermilab has tested two compressors for possible installation in the satellite refrigerator buildings of the Tevatron cryogenic system. Both Creare Inc. and Cryogenic Consultants Inc. have supplied units for evaluation. The Creare machine, a high speed centrifugal pump/compressor, yielded 60% adiabatic efficiency but had difficulty withstanding two-phase flow. Cryogenic Consultants provided a reciprocating unit which achieved 59% efficiency and, although lacking the operating characteristics of the turbomachine, endured throughout testing and was insensitive to two-phase flow. Test results are discussed

  8. Inverter fed high-speed solid-rotor induction motors for industrial applications

    Huppunen, J.; Pyrhoenen, J. [Lappeenranta Univ. of Technology (LUT) (Finland); Alamaeki, J. [Rotatek Finland Oy, Lappeenranta (Finland)

    2000-07-01

    An inverter fed 250 kW, 9000 min{sup -1} solid-rotor induction motor drive for an industrial compressor application is introduced. New designing methods for the electric motor have made it possible to create a high efficiency high-speed solid-rotor induction motor. The results of the research work are new motor structures that are also easy and economical to manufacture. This technology is very reliable and economical for compressor and pump applications in power range from 100 kW to 1000 kW. (orig.)

  9. Compressor Foundation Analysis Tool(COFANTO)

    Eijk, A.; Lentzen, S.S.K; Zuada Coelho, B.E.; Galanti, F.M.B.

    2012-01-01

    Reciprocating compressors are generally supported on a heavy concrete foundation. In spite of the large inertia and stiffness of the foundation, problems can occur due to interaction between the mechanical installation and the foundation. Two types of problems may occur. In the first type, the

  10. Computational analysis of a multistage axial compressor

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  11. Energy saving screw compressor technology; Energiebesparende schroefcompressortechnologie

    Moeller, A. [RefComp, Lonigo (Italy); Neus, M. [Delta Technics Engineering, Breda (Netherlands)

    2011-03-15

    Smart solutions to reduce the energy consumption are continuously part of investigation in the refrigeration technology. This article subscribed the technology on which way energy can be saved at the operation of screw compressors which are used in air conditioners and refrigerating machinery. The combination of frequency control and Vi-control (intrinsic volumetric ratio) such as researched in the laboratory of RefComp is for the user attractive because the energy efficiency during part load operation is much better. Smart uses of thermodynamics, electric technology and electronic control are the basics of these applications. According to the manufacturer's information it is possible with these new generation screw compressors to save approx. 26% energy in comparison with the standard screw compressor. [Dutch] In dit artikel wordt de technologie omschreven waarmee veel energie bespaard kan worden bij schroefcompressoren die worden gebruikt in airconditioningsystemen en koel- en vriesinstallaties. De combinatie van frequentieregeling en Vi- regeling (Vi is de intrinsieke volumetrische verhouding) zoals onderzocht in het laboratorium van RefComp biedt de gebruiker veel voordelen doordat de energie-efficintie van de compressor tijdens deellast enorm wordt verbeterd. Slim gebruik van thermodynamika, elektrotechniek en elektronica vormen de basis van deze toepassing. Volgens de fabrikant kan met deze nieuwe generatie schroefcompressoren circa 26 procent op het energiegebruik tijdens deellast worden bespaard in vergelijking met de standaard serie schroefcompressoren.

  12. Energy saving potential in existing industrial compressors

    Vittorini, Diego; Cipollone, Roberto

    2016-01-01

    The Compressed Air Sector accounts for a mean 10% worldwide electricity consumption, which ensures about its importance, when energy saving and CO_2 emissions reduction are in question. Since the compressors alone account for 15% overall industry electricity consumption, it appears vital to pay attention to machine performances. The paper presents an overview of present compressor technology and focuses on saving directions for screw and sliding vanes machines, according to data provided by the Compressed Air and Gas Institute and PNEUROP. Data were processed to obtain consistency with fixed reference pressures and organized as a function of main operating parameters. Each sub-term, contributing to the overall efficiency (adiabatic, volumetric, mechanical, electric, organic), was considered separately: the analysis showed that the thermodynamic improvement during compression achievable by splitting the compression in two stages, with a lower compression ratio, opens the way to significantly reduce the energy specific consumption. - Highlights: • Compressors technology overview in industrial compressed air systems. • Market compressors efficiency baseline definition. • Energy breakdown and evaluation of main efficiency terms. • Assessment of air cooling-related energy saving potential. • Energy specific consumption reduction through dual stage compression.

  13. Composite hub/metal blade compressor rotor

    Yao, S.

    1978-01-01

    A low cost compressor rotor was designed and fabricated for a small jet engine. The rotor hub and blade keepers were compression molded with graphite epoxy. Each pair of metallic blades was held in the hub by a keeper. All keepers were locked in the hub with circumferential windings. Feasibility of fabrication was demonstrated in this program.

  14. Positive feedback stabilization of centrifugal compressor surge

    Willems, Frank; Heemels, W.P.M.H.; de Jager, Bram; Stoorvogel, Antonie Arij

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  15. Positive feedback stabilization of centrifugal compressor surge

    Willems, F.P.T.; Heemels, W.P.M.H.; Jager, de A.G.; Stoorvogel, A.A.

    2002-01-01

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  16. Centrifugal compressor tip clearance and impeller flow

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

    2016-11-15

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

  17. Centrifugal compressor tip clearance and impeller flow

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

    2016-01-01

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

  18. Configuration and testing of a saturated vapor helium compressor

    Ludwigsen, J.L.; Iwasa, Y.; Smith, J.L.

    1986-01-01

    A saturated vapor helium compressor was designed and tested as a component of a helium-temperature refrigeration cycle. The use of the cold compressor allows reduction of both the precooling heat exchanger area and main compressor size compared to a conventional cycle due to increased pressure of the return gas. The compressor tested was a single-piston reciprocating device which was controlled with programmable hydraulic/pneumatic logic. The compressor was mounted at the cold end of a CTI Model 1400 helium liquefier. An average compression ratio of 2.4 was obtained and an average efficiency of 82% was achieved. In computing compressor efficiency, external heat leaks to the compressor were neglected

  19. Fault detection and diagnosis for refrigerator from compressor sensor

    Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

    2016-12-06

    A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.

  20. Piezoelectric Motors, an Overview

    Karl Spanner

    2016-02-01

    Full Text Available Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ultrasonic motors, inertia-drive, and piezo-walk-drive. In this review, a comprehensive summary of piezoelectric motors, with their classification from initial idea to recent progress, is presented. This review also includes some of the industrial and commercial applications of piezoelectric motors that are presently available in the market as actuators.

  1. Modification of a compressor performance test bench for liquid slugging observation in refrigeration compressors

    Ola, Max; Thomas, Christiane; Hesse, Ullrich

    2017-08-01

    Compressor performance test procedures are defined by the standard DIN EN 13771, wherein a variety of possible calorimeter and flow rate measurement methods are suggested. One option is the selection of two independent measurement methods. The accuracies of both selected measurement methods are essential. The second option requires only one method. However the measurement accuracy of the used device has to be verified and recalibrated on a regular basis. The compressor performance test facility at the Technische Universitaet Dresden uses a calibrated flow measurement sensor, a hot gas bypass and a mixed flow heat exchanger. The test bench can easily be modified for tests of various compressor types at different operating ranges and with various refrigerants. In addition, the modified test setup enables the investigation of long term liquid slug and its effects on the compressor. The modification comprises observational components, adjustments of the control system, safety measures and a customized oil recirculation system for compressors which do not contain an integrated oil sump or oil level regulation system. This paper describes the setup of the test bench, its functional principle, the key modifications, first test results and an evaluation of the energy balance.

  2. Kinetics of a gas adsorption compressor

    Chan, C. K.; Tward, E.; Elleman, D. D.

    1984-01-01

    Chan (1981) has suggested that a process based on gas adsorption could be used as a means to drive a Joule-Thomson (J-T) device. The resulting system has several advantages. It is heat powered, it has no sealing, there are no mechanical moving parts, and no active control is required. In the present investigation, a two-phase model is used to analyze the transients of a gas adsorption compressor. The modeling of the adsorption process is based on a consideration of complete thermal and mechanical equilibrium between the gaseous phase and the adsorbed gas phase. The experimental arrangement for two sets of kinetic tests is discussed, and data regarding the experimental results are presented in graphs. For a theoretical study, a two-phase model was developed to predict the transient behavior of the compressor. A computer code was written to solve the governing equations with the aid of a standard forward marching predictor-corrector method.

  3. Rotating flux compressor for energy conversion

    Chowdhuri, P.; Linton, T.W.; Phillips, J.A.

    1983-01-01

    The rotating flux compressor (RFC) converts rotational kinetic energy into an electrical output pulse which would have higher energy than the electrical energy initially stored in the compressor. An RFC has been designed in which wedge-shaped rotor blades pass through the air gaps between successive turns of a solenoid, the stator. Magnetic flux is generated by pulsing the stator solenoids when the inductance is a maximum, i.e., when the flux fills the stator-solenoid volume. Connecting the solenoid across a load conserves the flux which is compressed within the small volume surrounding the stator periphery when the rotor blades cut into the free space between the stator plates, creating a minimum-inductance condition. The unique features of this design are: (1) no electrical connections (brushes) to the rotor; (2) no conventional windings; and (3) no maintenance. The device has been tested up to 5000 rpm of rotor speed

  4. High stability design for new centrifugal compressor

    Kanki, H.; Katayama, K.; Morii, S.; Mouri, Y.; Umemura, S.; Ozawa, U.; Oda, T.

    1989-01-01

    It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions.

  5. Centrifugal Compressors, Flow Phenomena and Performance.

    1980-11-01

    r2 = 1.975 situated near diffuser exit/ collector entrance. Total temperature measure- ments have been performed at the compressor inlet and exit...non-square mesh is used in a two-dimensional flow calculation. In fact, this term is compounded of the product of a constant coefficient multiplying the...terms of the finite difference equations are evaluated from the zeroth approximation, i.e., the solution of Katsanis and McNally (1), while parabolic

  6. Advanced Compressor for Long Life Space Cryocoolers

    1994-11-01

    625 and 718, or beryllium copper. When both high-yield and high- fatigue strength are required, Inconel 718 is usually the material of choice. As shown...with wear debris and life in the case of rubbing seals, and long-term stability and alignment in the case of precision noncontacting clearance seals, are...the bearings’ wear pv, and hence increased life, with decreasing stroke. In summary, the results of the compressor optimization studies showed that a

  7. Analysis of performance for centrifugal steam compressor

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters.

  8. Analysis of performance for centrifugal steam compressor

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo

    2016-01-01

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters

  9. Axial forces in centrifugal compressor couplings

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  10. Stepping Motor - Hydraulic Motor Servo Drives for an NC Milling ...

    In this paper the retrofit design of the control system of an NC milling machine with a stepping motor and stepping motor - actuated hydraulic motor servo mechanism on the machines X-axis is described. The servo designed in the course of this study was tested practically and shown to be linear - the velocity following errors ...

  11. New concept single screw compressors and their manufacture technology

    Feng, Q.; Liu, F.; Chang, L.; Feng, C.; Peng, C.; Xie, J.; van den Broek, M.

    2017-08-01

    Single screw compressors were generally acknowledged as one of the nearly perfect machines by compressor researchers and manufacturers. However the rapid wear of the star-wheel in a single screw compressor during operation is a key reason why it hasn’t previously joined the main current compressors’ market. After more than ten years of effective work, the authors of this paper have proposed a new concept single screw compressor whose mesh-couple profile is enveloped with multi-column. Also a new design method and manufacture equipment for this kind of compressor have been developed and are described in this paper. A lot of prototype tests and a long period of industrial operations under full loading conditions have shown that the mesh-couple profiles of the new concept single compressors have excellent anti-wearness.

  12. Separation of compressor oil from helium

    Strauss, R.; Perrotta, K.A.

    1982-01-01

    Compression of helium by an oil-sealed rorary screw compressor entrains as much as 4000 parts per million by weight of liquid and vapor oil impurities in the gas. The reduction below about 0.1 ppm for cryogenic applications is discussed. Oil seperation equipment designed for compressed air must be modified significantly to produce the desired results with helium. The main differences between air and helium filtration are described. A description of the coalescers is given with the continuous coalescing of liquid mist from air or other gas illustrated. Oil vapor in helium is discussed in terms of typical compressor oils, experimental procedure for measuring oil vapor concentration, measured volatile hydrocarbons in the lubricants, and calculated concentration of oil vapor in Helium. Liquid oil contamination in helium gas can be reduced well below 0.1 ppm by a properly designed multiple state coalescing filter system containing graded efficiency filter elements. The oil vapor problem is best attached by efficiently treating the oil to remove most of the colatiles before charging the compressor

  13. The analysis on centrifugal compressor rotating stall

    Kim, Ji Hwan; Kim, Kwang Ho; Shin, You Hwan

    2003-01-01

    In the present study, the performance characteristics and the number of stall cell during rotating stall of a centrifugal air compressor were experimentally investigated. Rotating stall in the vaneless diffuser were investigated by measuring unsteady pressure fluctuations at several different diffuser radius using a high frequency pressure transducer. The number of stall cell and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly forced on the analysis for the stall cell number and its propagation speed unstable operating region of the compressor. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates. To obtain the visualize the existence rotating stall, auto-correlation function and the frequency spectra of the pressure fluctuations were measured at r/r2=1.52. When the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct of the compressor. And the flow coefficient is lower than 0.086, several stall cell groups of discrete frequencies are observed

  14. Real-time trend monitoring of gas compressor stations

    Van Hardeveld, T. (Nova, an Alberta Corp., AB (Canada))

    1991-02-01

    The authors' company has developed a machinery health monitoring system (MHealth) for short-term and long-term historical trending and analysis of data from its 40 gas compressor stations. The author discusses the benefits of real-time trending in troubleshooting operations, in preventative maintenance scheduling and cites specific applications in the startup operations of several new gas compressor/centrifugal compressor units.

  15. Method and refrigerants for replacing existing refrigerants in centrifugal compressors

    Kopko, W.L.

    1991-01-01

    This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

  16. Experimental Pressure-Volume diagrams of scroll compressors

    Picavet, Alain; Ginies, Pierre

    2014-01-01

    This paper presents the results of tests led with scroll compressors to establish pressure-volume diagrams. Two compressors were thinly instrumented with pressure and displacement sensors so as to follow the whole compression process, from suction to exhaust. A gear coder was set to mark off the closing and opening of gas pockets, and to study the speed variations occurring during a single rotation. These tests help to understand the various phenomena met in a compressor, such as back-flow, o...

  17. Variable speed gas engine-driven air compressor system

    Morgan, J. R.; Ruggles, A. E.; Chen, T. N.; Gehret, J.

    1992-11-01

    Tecogen Inc. and Ingersoll-Rand Co. as a subcontractor have designed a nominal 150-hp gas engine-driven air compressor utilizing the TECODRIVE 8000 engine and the Ingersoll-Rand 178.5-mm twin screw compressor. Phase 1 included the system engineering and design, economic and applications studies, and a draft commercialization plan. Phase 2 included controls development, laboratory prototype construction, and performance testing. The testing conducted verified that the compressor meets all design specifications.

  18. Economics of water injected air screw compressor systems

    Madhav, K. V.; Kovacevic, A.

    2015-01-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an in...

  19. Aspirated Compressors for High Altitude Engines, Phase I

    National Aeronautics and Space Administration — Aurora Flight Sciences proposes to incorporate aspirated compressor technology into a high altitude, long endurance (HALE) concept engine. Aspiration has been proven...

  20. Economics of water injected air screw compressor systems

    Venu Madhav, K.; Kovačević, A.

    2015-08-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an investigation carried out to determine the current limitations of water injected screw compressor systems and how these could be overcome in the 15-315 kW power range and delivery pressures of 6-10 bar. Modern rotor profiles and approach to sealing and cooling allow reasonably inexpensive air end design. The prototype of the water injected screw compressor air system was built and tested for performance and reliability. The water injected compressor system was compared with the oil injected and oil free compressor systems of the equivalent size including the economic analysis based on the lifecycle costs. Based on the obtained results, it was concluded that water injected screw compressor systems could be designed to deliver clean air free of oil contamination with a better user value proposition than the oil injected or oil free screw compressor systems over the considered range of operations.

  1. Possibility of Thermomechanical Compressor Application in Desalination Plants

    Blagin, E. V.; Shimanov, A. A.; Uglanov, D. A.; Korneev, S. S.

    2018-01-01

    This article deals with estimation of thermocompressor operating possibility in desalination plant with mechanical vapour compressor. In this plant thermocompressor is used instead of commonly used centrifugal compressor. Preliminary analysis shows that such plant is able to operate, however, power consumption is 3.5-6.5 higher in comparison with traditional MVC plant. In turn, utilization of thermocompressor allows avoiding usual high-frequency drive of centrifugal compressor. Drives with frequency of 50 Hz are enough for thermocompressor when centrifugal compressor requires drives with frequency up to 500 Hz and higher. Approximate thermocompressor dimensions are estimated.

  2. Rotating stall simulation for axial and centrifugal compressors

    Halawa, Taher; Gadala, Mohamed S.

    2017-05-01

    This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

  3. Effect of surface roughness and Reynolds number on compressor cascade performance

    Back, Seung Chul; Song, Seung Jin

    2009-01-01

    An experimental work has been conducted in a linear compressor cascade to find out the effect of surface roughness and Reynolds number. Surveys were conducted with different roughness size and Reynolds number. The k s /c value of each roughness is 0.0006, 0.0090, 0.00150, 0.00213, and 0.00425. The range of Reynolds number is 300,000∼600,000 and conducted with roughened blade, which roughness Ra is 2.89 microns. Flow pressure, velocity, and angle have been found out via 5 hole probe. Pressure loss and deviation increased with increasing roughness. In the low Reynolds number under 500,000, tested roughness does not affect to the performance of compressor cascade. However, roughness is very sensitive to pressure loss in high Reynolds number over 550,000.

  4. Compressor Performance Scaling in the Presence of Non-Uniform Flow

    Hill, David Jarrod

    Fuselage-embedded engines in future aircraft will see increased flow distortions due to the ingestion of airframe boundary layers. This reduces the required propulsive power compared to podded engines. Inlet flow distortions mean that localized regions of flow within the fan and first stage compressor are operating at off-design conditions. It is important to weigh the benefit of increased vehicle propulsive efficiency against the resultant reduction in engine efficiency. High computational cost has limited most past research to single distortion studies. The objective of this thesis is to extract scaling laws for transonic compressor performance in the presence of various distortion patterns and intensities. The machine studied is the NASA R67 transonic compressor. Volumetric source terms are used to model rotor and stator blade rows. The modelling approach is an innovative combination of existing flow turning and loss models, combined with a compressible flow correction. This approach allows for a steady calculation to capture distortion transfer; as a result, the computational cost is reduced by two orders of magnitude. At peak efficiency, the rotor work coefficient and isentropic efficiency are matched within 1.4% of previously published experimental results. A key finding of this thesis is that, in non-uniform flow, the state-of-the-art loss model employed is unable to capture the impact of variations in local flow coefficient, limiting the analysis of local entropy generation. New insight explains the mechanism governing the interaction between a total temperature distortion and a compressor rotor. A parametric study comprising 16 inlet distortions reveals that for total temperature distortions, upstream flow redistribution and rotor diffusion factor changes are shown to scale linearly with distortion severity. Linear diffusion factor scaling does not hold true for total pressure distortions. For combined total temperature and total pressure distortions, the

  5. Investigation of the compressor part-load behaviour and its effects on the per annum energy consumption of the air conditioner; Untersuchung des Kompressor-Teillastverhaltens im Hinblick auf den Jahresverbrauch der Klimaanlage

    Martin, Klaus; Lechner, Bernhard [Virtual Vehicle. Kompetenzzentrum - Das virtuelle Fahrzeug Forschungsgesellschaft mbH (ViF), Graz (Austria); Rieberer, Rene [Technische Univ. Graz (Austria); Moenkediek, Thomas [Audi AG, Ingolstadt (Germany)

    2010-07-01

    The air conditioning system is one of the most important ancillary units of a motor vehicle. Energetic optimization of air conditioners has been a key issue of research at AUDI AG during the past few years. As a rule, the cooling capacity of the air conditioner is controlled by adapting the compressor lift if the compressor is driven by the car engine and control via the rotational speed is not possible. As air conditioners ted to be designed for extreme conditions, the compressor will work at part load in most operating conditions. Optimization of the energetic efficiency of the air conditioner also means to look at the part-load behaviour of the compressor. Simulations have been used successfully by AUDI AG for many years now; the have helped to shorten development times and improve the product quality. The contribution describes an advanced model of a swivel plate compressor of a R134a cooling cycle with particular consideration of part-lift operation. The simulation model is based on measurements with continous recording of the piston lift. The focus is on the influence of reduced lift on the compressor efficiency. Another point of interest is the successful integration of the compressor model in the overall refrigerating cycle model which will be used for simulations of system performance and efficiency and for further optimization of the air conditioner. (orig.)

  6. Fuel efficiency, availability and compressor station configuration

    Lubomirsky, Matt; Kurz, Rainer [Solar Turbines Inc., San Diego, CA (United States); Klimov, Pavel [Intergas Central Asia, Astana (Kazakhstan)

    2009-12-19

    Compressor stations play a very important role in the success of a gas pipeline design and a careful selection of centrifugal compressors and drivers are key aspects for the success of the project. The state of the art design available today for this equipment provides overall high thermodynamic performance and consequently minimizes installed power requirements and energy usage with significant savings on operating expenses during the economic life of the project For any application of machinery in a pipeline compression station, one of the key questions to answer is the number of units to install to meet the flow requirements of the pipeline. Depending on the load profile of the pipeline, the answers may look different. Other factors to consider include the fact that gas turbines can produce a significant amount of additional power at lower ambient temperatures. So, even for constant load of the pipeline, the relative load of the driver changes. In this paper, a typical transcontinental pipeline with multiple compressor stations is evaluated. The determination of the exact hydraulic behavior of the pipeline is part of the modeling effort. The site ambient conditions, with a significant swing in ambient temperatures are considered. The issue discussed in this paper evolves around the availability that can be achieved with various configurations, based on actually achieved reliability and availability numbers. The other large impact on operating costs, fuel consumption will be discussed. Here, the choice of the number of installed units has a distinct impact on annual fuel consumption, as well as the capacity of the pipeline during various scenarios. (author)

  7. Linear pneumatic actuator

    Avram Mihai

    2017-01-01

    Full Text Available The paper presents a linear pneumatic actuator with short working stroke. It consists of a pneumatic motor (a simple stroke cylinder or a membrane chamber, two 2/2 pneumatic distributors “all or nothing” electrically commanded for controlling the intake/outtake flow to/from the active chamber of the motor, a position transducer and a microcontroller. There is also presented the theoretical analysis (mathematical modelling and numerical simulation accomplished.

  8. Linear pneumatic actuator

    Avram Mihai; Niţu Constantin; Bucşan Constantin; Grămescu Bogdan

    2017-01-01

    The paper presents a linear pneumatic actuator with short working stroke. It consists of a pneumatic motor (a simple stroke cylinder or a membrane chamber), two 2/2 pneumatic distributors “all or nothing” electrically commanded for controlling the intake/outtake flow to/from the active chamber of the motor, a position transducer and a microcontroller. There is also presented the theoretical analysis (mathematical modelling and numerical simulation) accomplished.

  9. Full-order Luenberger observer based on fuzzy-logic control for sensorless field-oriented control of a single-sided linear induction motor.

    Holakooie, Mohammad Hosein; Ojaghi, Mansour; Taheri, Asghar

    2016-01-01

    This paper investigates sensorless indirect field oriented control (IFOC) of SLIM with full-order Luenberger observer. The dynamic equations of SLIM are first elaborated to draw full-order Luenberger observer with some simplifying assumption. The observer gain matrix is derived from conventional procedure so that observer poles are proportional to SLIM poles to ensure the stability of system for wide range of linear speed. The operation of observer is significantly impressed by adaptive scheme. A fuzzy logic control (FLC) is proposed as adaptive scheme to estimate linear speed using speed tuning signal. The parameters of FLC are tuned using an off-line method through chaotic optimization algorithm (COA). The performance of the proposed observer is verified by both numerical simulation and real-time hardware-in-the-loop (HIL) implementation. Moreover, a detailed comparative study among proposed and other speed observers is obtained under different operation conditions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Dual-worm screw compressors; Compresseurs bi-vis

    Baleydier, J P [Bitzer France, 69 - Lyon (France)

    1998-12-31

    Low power worm-screw moto-compressors are used in any king of refrigerating machineries and more and more in air conditioning systems. This paper presents the principle of dual-screw moto-compressors: worm-screw technology, role of oil (lubrication, tightness, cooling), compression, internal pressure, power reduction, lubrication, economizer, operation, model selection and accessories. (J.S.)

  11. Sound reduction of air compressors using a systematic approach

    Moylan, Justin Tharp

    The noise emitted by portable electric air compressors can often be a nuisance or potentially hazardous to the operator or others nearby. Therefore, reducing the noise of these air compressors is desired. This research focuses on compressors with a reciprocating piston design as this is the most common type of pump design for portable compressors. An experimental setup was developed to measure the sound and vibration of the air compressors, including testing inside a semi-anechoic chamber. The design of a quiet air compressor was performed in four stages: 1) Teardown and benchmarking of air compressors, 2) Identification and isolation of noise sources, 3) Development of individual means to quiet noise sources, 4) Selection and testing of integrated solutions. The systematic approach and results for each of these stages will be discussed. Two redesigned solutions were developed and measured to be approximately 65% quieter than the previous unmodified compressor. An additional analysis was performed on the solutions selected by the participants involved in the selection process. This analysis involved determining which of the design criteria each participant considered most important when selecting solutions. The results from each participant were then compared to their educational background and experience and correlations were identified. The correlations discovered suggest that educational background and experience may be key determinants for the preference models developed.

  12. 78 FR 1162 - Cardiovascular Devices; Reclassification of External Cardiac Compressor

    2013-01-08

    .... FDA-2012-N-1173] Cardiovascular Devices; Reclassification of External Cardiac Compressor AGENCY: Food... external cardiac compressors as class III requiring premarket approval. The Cardiovascular Device... on CPR and emergency cardiovascular care (Ref. 1) conclude that ``real-time CPR prompting and...

  13. 46 CFR 154.534 - Cargo pumps and cargo compressors.

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154.534 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps and...

  14. Dual-worm screw compressors; Compresseurs bi-vis

    Baleydier, J.P. [Bitzer France, 69 - Lyon (France)

    1997-12-31

    Low power worm-screw moto-compressors are used in any king of refrigerating machineries and more and more in air conditioning systems. This paper presents the principle of dual-screw moto-compressors: worm-screw technology, role of oil (lubrication, tightness, cooling), compression, internal pressure, power reduction, lubrication, economizer, operation, model selection and accessories. (J.S.)

  15. Experiments with Liquid Propellant Jet Ignition in a Ballistic Compressor

    Birk, Avi

    1998-01-01

    .... The apparatus consists of an inline ballistic compressor and LP injector. The rebound of the ballistic compressor piston was arrested, trapping 40 to 55 MPa of 750 to 8500 C argon for ignition of circular jets in a windowed test chamber...

  16. [Lubricant-free piston compressors for mechanized medical instruments].

    Sabitov, V Kh; Repin, V A; Kil'kinov, A A

    1988-01-01

    Piston compressor without lubrication with air blow to packing rings by plunger, disposed in subpiston space, is recommended as the basic scheme of construction of a power supply unit for medical pneumatic tooling. The construction reduces a leak of the compressive medium, increasing the efficiency of a compressor and seal reliability.

  17. Analysis of ideal sorption compressor cycles operating with gas mixtures

    Tzabar, N.; ter Brake, H.J.M.

    2018-01-01

    Sorption-based compressors are thermally driven and because of the absence of moving parts they are vibration free, and have the potential for long life. Sorption-based compressors have been reported to operate Joule–Thomson (JT) cryogenic coolers with pure working fluids. However, using mixed

  18. Axial and Centrifugal Compressor Mean Line Flow Analysis Method

    Veres, Joseph P.

    2009-01-01

    This paper describes a method to estimate key aerodynamic parameters of single and multistage axial and centrifugal compressors. This mean-line compressor code COMDES provides the capability of sizing single and multistage compressors quickly during the conceptual design process. Based on the compressible fluid flow equations and the Euler equation, the code can estimate rotor inlet and exit blade angles when run in the design mode. The design point rotor efficiency and stator losses are inputs to the code, and are modeled at off design. When run in the off-design analysis mode, it can be used to generate performance maps based on simple models for losses due to rotor incidence and inlet guide vane reset angle. The code can provide an improved understanding of basic aerodynamic parameters such as diffusion factor, loading levels and incidence, when matching multistage compressor blade rows at design and at part-speed operation. Rotor loading levels and relative velocity ratio are correlated to the onset of compressor surge. NASA Stage 37 and the three-stage NASA 74-A axial compressors were analyzed and the results compared to test data. The code has been used to generate the performance map for the NASA 76-B three-stage axial compressor featuring variable geometry. The compressor stages were aerodynamically matched at off-design speeds by adjusting the variable inlet guide vane and variable stator geometry angles to control the rotor diffusion factor and incidence angles.

  19. Piston-Skirt Lubrication System For Compressor

    Schroeder, Edgar C.; Burzynski, Marion, Jr.

    1994-01-01

    Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

  20. DESIGN PARAMETERS OF CENTRIFUGAL COMPRESSOR INDUCER

    Saim KOÇAK

    1998-03-01

    Full Text Available Design characteristics of centrifugal compressor impellers working with compressible fluids are analyzed, and the design parameters of inducer are defined. The effects of incidence, deviation and deflection angles, relative eddy, rotating stall and Mach number are investigated. The relation between minimum relative Mach number of inducer and flow angle is investigated and it is observed that the minimum Mach number occurs for flow angle values between -680 and -520 . In the design, the effect of a 100 difference in flow angle is found to be less than 1 % on minimum relative Mach number.

  1. Retrofitting compressor engines to reduce emissions

    Collison, Melanie

    2011-01-01

    Cenovus Energy Inc. is upgrading its natural gas compression facilities at 37 sites it operates in Alberta. The project itself consists of a retrofit of the natural-fas fired engines that power the compressors that fill its natural gas sales pipe-line. Piping to capture fugitive natural gas will also be installed. These emissions will be used as fuel. The efficiency rating of such engine will be the same as a new fuel-injected engine. One of the challenge in the design of the parts of these engines ss to to ensure the least possible downtime to minimize production losses.

  2. Development of the virtual experimental bench on the basis of modernized research centrifugal compressor stage test unit with the 3D impeller.

    Aksenov, A. A.; Danilishin, A. M.; Dubenko, A. M.; Kozhukov, Y. V.

    2017-08-01

    Design modernization of the centrifugal compressor stage test bench with three dimensional impeller blades was carried out for the possibility of holding a series of experimental studies of different 3D impeller models. The studies relates to the problem of joint work of the impeller and the stationary channels of the housing when carrying out works on modernization with the aim of improving the parameters of the volumetric capacity or pressure in the presence of design constraints. The object of study is the experimental single end centrifugal compressor stage with the 3D impeller. Compressor stage consists of the 3D impeller, vaneless diffuser (VLD), outlet collector - folded side scroll and downstream pipe. The drive is a DC motor 75 kW. The increase gear (multiplier) was set between the compressor and DC motor, gear ratio is i = 9.8. To obtain the characteristics of the compressor and the flow area the following values were measured: total pressure, static pressure, direction (angles) of the stream in different cross sections. Additional pneumometric probes on the front wall of the VLD of the test bench have been installed. Total pressure probes and foster holes for the measurement of total and static pressure by the new drainage scheme. This allowed carrying out full experimental studies for two elements of centrifugal compressor stage. After the experimental tests the comprehensive information about the performance of model stage were obtained. Was measured geometric parameters and the constructed virtual model of the experimental bench flow part with the help of Creo Parametric 3.0 and ANSYS v. 16.2. Conducted CFD calculations and verification with experimental data. Identifies the steps for further experimental and virtual works.

  3. Thermal modelling of a dry revolving vane compressor

    Ooi, K. T.; Aw, K. T.

    2017-08-01

    The lubricant used in compressors serves to lubricate, to seal the gaps to reduce internal leakage and to a certain extent, to cool. However, a lubricant free compressor is attractive if lubricants become a source of contaminant, or in areas where the compressor needs be placed under any orientation, such as those in military or portable computing. In this paper, a thermal model for a dry revolving vane compressor is presented. This thermal model sets out to predict the steady-state operating temperatures of the compressor components. The lumped thermal conductance method was employed. The results of the components temperature will be presented and discussed. A high potential for overheating is observed at the shaft bearings.

  4. Safe and efficient operation of multistage cold compressor systems

    Kauschke, M.; Haberstroh, C.; Quack, H.

    1996-01-01

    Large refrigeration rates in the temperature range of super fluid helium can only be obtained with the help of centrifugal cold compressors. For the large 2 K systems, four compression stages are necessary to reach atmospheric pressure. Centrifugal cold compressors are quite sensitive to mass flow and suction temperature variations; but these have to be expected in a real system. The first step in the systems design is to find safe and efficient quasi-stationary modes of operation. The system which is being proposed for the TESLA refrigerators relies on two features. The first is to allow the room temperature screw compressor, downstream of the cold compressors to work occasionally with a subatmospheric suction pressure. The second is to stabilize the suction temperature of the third stage of compression at about 10 K. With these features it is possible, that in all modes of operation all four compressor stages operate exactly at their design point

  5. Combined cold compressor/ejector helium refrigerator cycle

    Schlafke, A.P.; Brown, D.P.; Wu, K.C.

    1984-01-01

    This chapter demonstrates how the use of a cold compressor in series with an ejector is an effective way to produce the desired low pressure in a helium refrigeration system. The cold compressor is tentatively located at the low pressure side below the J-T heat exchanger. The ejector is the first stage and the cold compressor is the second stage of the two-stage pumping system. A centrifugal, oil-bearing type compressor was installed on the R and D refrigerator at the Brookhaven National Laboratory. It is determined that the combined cold compressor and ejector system produces a lower temperature on the same load or more cooling at the same temperature compared with a system which uses an ejector alone. Results of the test showed a gain of 20%

  6. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  7. Novel Long Stroke Reciprocating Compressor for Energy Efficient Jaggery Making

    Rane, M. V.; Uphade, D. B.

    2017-08-01

    Novel Long Stroke Reciprocating Compressor is analysed for jaggery making while avoiding burning of bagasse for concentrating juice. Heat of evaporated water vapour along with small compressor work is recycled to enable boiling of juice. Condensate formed during heating of juice is pure water, as oil-less compressor is used. Superheat of compressor is suppressed by flow of superheated vapours through condensate. It limits heating surface temperature and avoids caramelization of sugar. Thereby improves quality of jaggery and eliminates need to use chemicals for colour improvement. Stroke to bore ratio is 0.6 to 1.2 in conventional reciprocating drives. Long stroke in reciprocating compressors enhances heat dissipation to surrounding by providing large surface area and increases isentropic efficiency by reducing compressor outlet temperature. Longer stroke increases inlet and exit valve operation timings, which reduces inertial effects substantially. Thereby allowing use of sturdier valves. This enables handling liquid along with vapour in compressors. Thereby supressing the superheat and reducing compressor power input. Longer stroke increases stroke to clearance ratios which increases volumetric efficiency and ability of compressor to compress through higher pressure ratios efficiently. Stress-strain simulation is performed in SolidWorks for gear drive. Long Stroke Reciprocating Compressor is developed at Heat Pump Laboratory, stroke/bore 292 mm/32 mm. It is operated and tested successfully at different speeds for operational stability of components. Theoretical volumetric efficiency is 93.9% at pressure ratio 2.0. Specific energy consumption is 108.3 kWhe/m3 separated water, considering free run power.

  8. Using the motor to monitor pump conditions

    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.

  9. Using the motor to monitor pump conditions

    Casada, D.

    1996-01-01

    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

  10. Low emissions system featured on compressor drive

    Curtis, T.

    1995-01-01

    A high speed power turbine is offered as an option with direct drive capability for pipeline compressors and other high-speed applications. As developed, it features ease of maintenance with rotor and nozzle assembly in a single cartridge to allow quick change-out or replacement of parts on site. The new compressor drive builds extensively on proven technology and is expected to provide lower installed and life-cycle costs per unit horsepower than previous units. During its development stages, M ampersand IE preformed cost and risk assessment of several design configurations and concluded that a derivative approach based on the standard unit was an optimal solution in the 39,000 shp range. A two-shaft gas turbine is expected to be applied in the industrial and commercial marine markets, including 50- and 60-Hertz power generation applications, pipeline compression, gas injection, and fast ferry commercial marine uses. Emissions controls for the system will include water or steam injection using a standard combustor or M and IE's DLE combustion system

  11. Tests of cold helium compressors at Fermilab

    Peterson, T.J.; Fuerst, J.D.

    1987-10-01

    Fermilab has tested two cold helium compressors for possible installation in the satellite refrigerator buildings of the Tevatron cryogenic system. Operating conditions required to obtain an overall Tevatron energy upgrade from 900 to 1000 GeV are (for each of 24 machines): 52 g/s mass flow rate, 0.7 atm inlet pressure, 1.4 atm exhaust pressure. Acceptable efficiency is in the 60% range. Both Creare, Inc., and Cryogenic Consultants, Inc. (CCI), have supplied units for evaluation. The Creare machine is a high speed centrifugal pump/compressor which yielded 60% adiabatic efficiency (including an approximately 20 watt heat leak) with a 1.0 atm inlet pressure and 55 g/s flow rate. Certain mechanical difficulties were present, chiefly the device's inability to withstand two-phase flow. CCI supplied a reciprocating unit which, after initial testing and modification, achieved 59% efficiency with an approximate 35 watt heat leak at a 0.7 atm inlet pressure and 48 g/s flow rate. Although the device lacks the smooth, quiet operating characteristics of a turbomachine, it has endured mechanically throughout testing and is entirely insensitive to two-phase flow

  12. Unsteady flow measurements in centrifugal compressors

    Bammert, K.; Mobarak, A.; Rautenberg, M.

    1976-01-01

    Centrifugal compressors and blowers are often used for recycling the coolant gas in gas-cooled reactors. To achieve the required high pressure ratios, highly loaded centrifugal compressors are built. The paper deals with unsteady flow measurements on highly loaded centrifugal impellers. Measurements of the approaching flow have been done with hot wires. The method of measurement enabled us to get the velocity distribution across the pitch ahead of the inducer. The static pressure signals along the shroud line has been discussed on the basis of some theoretical considerations. Accordingly the form of flow in the impeller and the wave flow or separation zones in the impeller can now be better interpreted. The importance of the unsteady nature of the relative flow, especially at impeller exit, is clearly demonstrated. Measurements with high responsive total pressure probes in the vicinity of impeller exit and the subsequent calculations have shown, that the instantaneous energy transfer at a certain point after the impeller may differ by more than 30% from the Euler work. Lastly, unsteady pressure measurements along the shroud line have been performed during surge and rotating stall. The surge signal have been analyzed in more detail and the mechanism of flow rupture and pressure recovery during a surge cycle is thoroughly discussed. (orig.) [de

  13. Compressor Part II: Volute Flow Predictions

    Yu-Tai Lee

    1999-01-01

    Full Text Available A numerical method that solves the Reynolds-averaged Navier-Stokes equations is used to study an inefficient component of a shipboard air-conditioning HCFC-124 compressor system. This high-loss component of the centrifugal compressor was identified as the volute through a series of measurements given in Part I of the paper. The predictions were made using three grid topologies. The first grid closes the connection between the cutwater and the discharge diffuser. The other two grids connect the cutwater area with the discharge diffuser. Experiments were performed to simulate both the cutwater conditions used in the predictions. Surface pressures along the outer wall and near the inlet of the volute were surveyed for comparisons with the predictions. Good agreements between the predicted results and the measurements validate the calculations. Total pressure distributions and flow stream traces from the prediction results support the loss distribution through the volute. A modified volute configuration is examined numerically for further loss comparison.

  14. Motor Neurons

    Hounsgaard, Jorn

    2017-01-01

    Motor neurons translate synaptic input from widely distributed premotor networks into patterns of action potentials that orchestrate motor unit force and motor behavior. Intercalated between the CNS and muscles, motor neurons add to and adjust the final motor command. The identity and functional...... in in vitro preparations is far from complete. Nevertheless, a foundation has been provided for pursuing functional significance of intrinsic response properties in motoneurons in vivo during motor behavior at levels from molecules to systems....

  15. 14 CFR 33.27 - Turbine, compressor, fan, and turbosupercharger rotors.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine, compressor, fan, and... Turbine, compressor, fan, and turbosupercharger rotors. (a) Turbine, compressor, fan, and... affect turbine, compressor, fan, and turbosupercharger rotor structural integrity will not be exceeded in...

  16. Modeling of surge in free-spool centrifugal compressors : experimental validation

    Gravdahl, J.T.; Willems, F.P.T.; Jager, de A.G.; Egeland, O.

    2004-01-01

    The derivation of a compressor characteristic, and the experimental validation of a dynamic model for a variable speed centrifugal compressor using this characteristic, are presented. The dynamic compressor model of Fink et al. is used, and a variable speed compressor characteristic is derived by

  17. Nonlinear dynamics and control strategies: On a energy harvester vibrating system with a linear form to non-ideal motor torquet

    de Pontes B. R.

    2012-07-01

    Full Text Available In this paper, we deal with the research of a vibrating model of an energy harvester device, including the nonlinearities in the model of the piezoelectric coupling and the non-ideal excitation. We show, using numerical simulations, in the analysis of the dynamic responses, that the harvested power is influenced by non-linear vibrations of the structure. Chaotic behavior was also observed, causing of the loss of energy throughout the simulation time. Using a perturbation technique, we find an approximate analytical solution for the non-ideal system. Then, we apply both two control techniques, to keep the considered system, into a stable condition. Both the State Dependent Ricatti Equation (SDRE control as the feedback control by changing the energy of the oscillator, were efficient in controlling of the considered non-ideal system.

  18. Modal characteristics and fatigue strength of compressor blades

    Kim, Kyung Kook; Lee, Young Shin

    2014-01-01

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  19. Modal characteristics and fatigue strength of compressor blades

    Kim, Kyung Kook [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Lee, Young Shin [Chungnam National University, Daejeon (Korea, Republic of)

    2014-04-15

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  20. Numerical simulation investigation on centrifugal compressor performance of turbocharger

    Li, Jie; Yin, Yuting; Li, Shuqi; Zhang, Jizhong

    2013-01-01

    In this paper, the mathematical model of the flow filed in centrifugal compressor of turbocharger was studied. Based on the theory of computational fluid dynamics (CFD), performance curves and parameter distributions of the compressor were obtained from the 3-D numerical simulation by using CFX. Meanwhile, the influences of grid number and distribution on compressor performance were investigated, and numerical calculation method was analyzed and validated, through combining with test data. The results obtained show the increase of the grid number has little influence on compressor performance while the grid number of single-passage is above 300,000. The results also show that the numerical calculation mass flow rate of compressor choke situation has a good consistent with test results, and the maximum difference of the diffuser exit pressure between simulation and experiment decrease to 3.5% with the assumption of 6 kPa additional total pressure loss at compressor inlet. The numerical simulation method in this paper can be used to predict compressor performance, and the difference of total pressure ratio between calculation and test is less than 7%, and the total-to-total efficiency also have a good consistent with test.