Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection

Directory of Open Access Journals (Sweden)

Ying Zhu

2018-06-01

Full Text Available This paper presents a novel third harmonic voltage differential stator grounding protection (THV-DSGP method combining the adaptive coefficient and fixed coefficient. It can solve the protection sensitivity degradation problem when the insulation resistance of stator winding to ground is slowly declining. This protection method retains the advantages of the adaptive coefficient, which is to maintain high sensitivity in case of an instantaneous ground fault. Moreover, the fixed coefficient can remember the initial insulation state of the stator winding and prevent relay failure when the stator insulation is slowly declining. In addition, due to zero-sequence voltage disconnection (ZSVD often leading to malfunctioning of the THV stator ground protection, the existing criterion of the ZSVD was improved according to the electrical characteristics of the generator when ZSVD happens. THV-DSGP with both adaptive coefficient and fixed coefficient was simulated in the Matlab/Simulink. The simulation results show that the proposed protection can be applied to the slow ground fault of the stator winding. Furthermore, the improved criterion of ZSVD can effectively distinguish the stator metal earth fault and the secondary loop break of the zero-sequence voltage.

Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

Directory of Open Access Journals (Sweden)

Shoudao Huang

2016-09-01

Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

Influence of Upstream and Downstream Compressor Stators on Rotor Exit Flow Field

Directory of Open Access Journals (Sweden)

Nicole L. Key

2014-01-01

Full Text Available Measurements acquired at the rotor exit plane illuminate the interaction of the rotor with the upstream vane row and the downstream vane row. The relative phase of the upstream and downstream vane rows is adjusted using vane clocking so that the effect of the upstream propagating potential field from the downstream stator can be distinguished from the effects associated with the wakes shed from the upstream stator. Unsteady absolute flow angle information shows that the downstream potential field causes the absolute flow angle to increase in the vicinity of the downstream stator leading edge. The presence of Stator 1 wake is also detected at this measurement plane using unsteady total pressure data. The rotor wakes are measured at different circumferential locations across the vane passage, and the influence of Stator 1 wake on the suction side of the rotor wake is evident. Also, the influence of the downstream stator is detected on the pressure side of the rotor wake for a particular clocking configuration. Understanding the role of the surrounding vane rows on rotor wake development will lead to improved comparison between experimental data and results from computational models.

Vibrational Characteristics of ring-type ultrasonic motor stator using ESPI

International Nuclear Information System (INIS)

Jung, Hyun Kyu; Paik, Sung Hoon; Kim, Seung Ho; Park, Ki Jun; Wang, Young Sung

2001-01-01

A stator of ring-type ultrasonic motor composed of the piezoelectric ceramic and the elastic metal was made to generate the travelling wave. Vibrational behavior of the stator was simulated by a finite element analysis using ATILA program and was measured by the electronic speckle pattern interferometry (ESPI) method. The resonance frequencies and vibration modes were analysed depending upon the comparison between the finite element analysis and ESPI measurement. The optimal vibration mode and frequency was estimated to be 7th resonant mode which was corresponded to the measured frequency of 39 KHz. It could be concluded that this fabricated stator can be applied for ring-type ultrasonic motor.

Automated Cable Preparation for Robotized Stator Cable Winding

Directory of Open Access Journals (Sweden)

Erik Hultman

2017-04-01

Full Text Available A method for robotized cable winding of the Uppsala University Wave Energy Converter generator stator has previously been presented and validated. The purpose of this study is to present and validate further developments to the method: automated stand-alone equipment for the preparation of the winding cables. The cable preparation consists of three parts: feeding the cable from a drum, forming the cable end and cutting the cable. Forming and cutting the cable was previously done manually and only small cable drums could be handled. Therefore the robot cell needed to be stopped frequently. The new equipment was tested in an experimental robot stator cable winding setup. Through the experiments, the equipment was validated to be able to perform fully automated and robust cable preparation. Suggestions are also given on how to further develop the equipment with regards to performance, robustness and quality. Hence, this work represents another important step towards demonstrating completely automated robotized stator cable winding.

Stator winding service life analysis of wet winding motor RCP

International Nuclear Information System (INIS)

Yeoh Eingyee; Li Linsen; Wang Ziguan; Shen Feng

2017-01-01

The reactor coolant pump type RUV of KSB is specially designed for the Westinghouse AP1000 reactor. It is hermetically sealed, wet winding motor pump. This wet winding motor concept has higher efficiency as compared to a canned motor since there are no eddy current losses, but this makes the stator cable insulator face the challenge of degradation by γ-irradiation in coolant. Radiation dose at the RUV is evaluated in interest from the material degradation point of view and the service life of stator winding in RUV is preliminarily analyzed. The values obtained are less than the dose rate and the dose which change the mechanical properties of the insulator material. According to the preliminary analysis, it can be concluded that the degradation of cable insulator of stator winding by γ-irradiation in coolant is negligible for the 60 years' service life of reactor coolant pump. This result also ensures crosslinked polyethylene used as cable insulator of stator winding is reliable in reactor coolant pump. (author)

An electrostatic lower stator axial gap wobble motor: design and fabrication

NARCIS (Netherlands)

Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt

1995-01-01

The fabrication, initial modelling and first results of an electrostatic lower stator axial gap wobble motor are presented. The four mask fabrication process is based on polysilicon surface micromachining techniques. Three to twelve stator pole wobble motor designs have been realized with rotor

Study of controlled diffusion stator blading. 1. Aerodynamic and mechanical design report

Science.gov (United States)

Canal, E.; Chisholm, B. C.; Lee, D.; Spear, D. A.

1981-01-01

Pratt & Whitney Aircraft is conducting a test program for NASA in order to demonstrate that a controlled-diffusion stator provides low losses at high loadings and Mach numbers. The technology has shown great promise in wind tunnel tests. Details of the design of the controlled diffusion stator vanes and the multiple-circular-arc rotor blades are presented. The stage, including stator and rotor, was designed to be suitable for the first-stage of an advanced multistage, high-pressure compressor.

Rotor Wake/Stator Interaction Noise Prediction Code Technical Documentation and User's Manual

Science.gov (United States)

Topol, David A.; Mathews, Douglas C.

2010-01-01

This report documents the improvements and enhancements made by Pratt & Whitney to two NASA programs which together will calculate noise from a rotor wake/stator interaction. The code is a combination of subroutines from two NASA programs with many new features added by Pratt & Whitney. To do a calculation V072 first uses a semi-empirical wake prediction to calculate the rotor wake characteristics at the stator leading edge. Results from the wake model are then automatically input into a rotor wake/stator interaction analytical noise prediction routine which calculates inlet aft sound power levels for the blade-passage-frequency tones and their harmonics, along with the complex radial mode amplitudes. The code allows for a noise calculation to be performed for a compressor rotor wake/stator interaction, a fan wake/FEGV interaction, or a fan wake/core stator interaction. This report is split into two parts, the first part discusses the technical documentation of the program as improved by Pratt & Whitney. The second part is a user's manual which describes how input files are created and how the code is run.

Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

Science.gov (United States)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

The Modeling and Simulation of Thermal Analysis at Hydro Generator Stator Winding Insulation

Directory of Open Access Journals (Sweden)

Mihaela Raduca

2006-10-01

Full Text Available This paper presents the modelling and simulation of thermal analysis at hydro generator stator winding. The winding stator is supplied at high voltage of 11 kV for high power hydro generator. To present the thermal analysis for stator winding is presented at supply of coil by 11 kV, when coil is heat and thermal transfer in insulation at ambient temperature.

Status of the Ford program to evaluate ceramics for stator applications in automotive gas turbine engines

Science.gov (United States)

Trela, W.

1980-01-01

The paper reviews the progress of the major technical tasks of the DOE/NASA/Ford program Evaluation of Ceramics for Stator Applications in Automotive Gas Turbine Engines: reliability prediction, stator fabrication, material characterization, and stator evaluation. A fast fracture reliability model was prepared for a one-piece ceramic stator. Periodic inspection results are presented.

Electrical machines and assemblies including a yokeless stator with modular lamination stacks

Science.gov (United States)

Qu, Ronghai; Jansen, Patrick Lee; Bagepalli, Bharat Sampathkumar; Carl, Jr., Ralph James; Gadre, Aniruddha Dattatraya; Lopez, Fulton Jose

2010-04-06

An electrical machine includes a rotor with an inner rotor portion and an outer rotor portion, and a double-sided yokeless stator. The yokeless stator includes modular lamination stacks and is configured for radial magnetic flux flow. The double-sided yokeless stator is concentrically disposed between the inner rotor portion and the outer rotor portion of the electrical machine. Examples of particularly useful embodiments for the electrical machine include wind turbine generators, ship propulsion motors, switch reluctance machines and double-sided synchronous machines.

A dynamic model of the piezoelectric traveling wave rotary ultrasonic motor stator with the finite volume method.

Science.gov (United States)

Renteria Marquez, I A; Bolborici, V

2017-05-01

This manuscript presents a method to model in detail the piezoelectric traveling wave rotary ultrasonic motor (PTRUSM) stator response under the action of DC and AC voltages. The stator is modeled with a discrete two dimensional system of equations using the finite volume method (FVM). In order to obtain accurate results, a model of the stator bridge is included into the stator model. The model of the stator under the action of DC voltage is presented first, and the results of the model are compared versus a similar model using the commercial finite element software COMSOL Multiphysics. One can observe that there is a difference of less than 5% between the displacements of the stator using the proposed model and the one with COMSOL Multiphysics. After that, the model of the stator under the action of AC voltages is presented. The time domain analysis shows the generation of the traveling wave in the stator surface. One can use this model to accurately calculate the stator surface velocities, elliptical motion of the stator surface and the amplitude and shape of the stator traveling wave. A system of equations discretized with the finite volume method can easily be transformed into electrical circuits, because of that, FVM may be a better choice to develop a model-based control strategy for the PTRUSM. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental and Numerical Study on Performance of Ducted Hydrokinetic Turbines with Pre-Swirl Stator Blades.

Science.gov (United States)

Gish, Andrew

2015-11-01

Ducts (also called shrouds) have been shown to improve performance of hydrokinetic turbines in some situations, bringing the power coefficient (Cp) closer to the Betz limit. Here we investigate optimization of the duct design as well as the addition of stator blades upstream of the turbine rotor to introduce pre-swirl in the flow. A small scale three-bladed turbine was tested in a towing tank. Three cases (bare turbine, with duct, and with duct and stators) were tested over a range of flow speeds. Important parameters include duct cross-sectional shape, blade-duct gap, stator cross-sectional shape, and stator angle. For each test, Cp was evaluated as a function of tip speed ratio (TSR). Experimental results were compared with numerical simulations. Results indicate that ducts and stators can improve performance at slower flow speeds and lower the stall speed compared to a bare turbine, but may degrade performance at higher speeds. Ongoing efforts to optimize duct and stator configurations will be discussed.

Evaluating transient performance of servo mechanisms by analysing stator current of PMSM

Science.gov (United States)

Zhang, Qing; Tan, Luyao; Xu, Guanghua

2018-02-01

Smooth running and rapid response are the desired performance goals for the transient motions of servo mechanisms. Because of the uncertain and unobservable transient behaviour of servo mechanisms, it is difficult to evaluate their transient performance. Under the effects of electromechanical coupling, the stator current signals of a permanent-magnet synchronous motor (PMSM) potentially contain the performance information regarding servo mechanisms in use. In this paper, a novel method based on analysing the stator current of the PMSM is proposed for quantifying the transient performance. First, a vector control model is constructed to simulate the stator current behaviour in the transient processes of consecutive speed changes, consecutive load changes, and intermittent start-stops. It is discovered that the amplitude and frequency of the stator current are modulated by the transient load torque and motor speed, respectively. The stator currents under different performance conditions are also simulated and compared. Then, the stator current is processed using a local means decomposition (LMD) algorithm to extract the instantaneous amplitude and instantaneous frequency. The sample entropy of the instantaneous amplitude, which reflects the complexity of the load torque variation, is calculated as a performance indicator of smooth running. The peak-to-peak value of the instantaneous frequency, which defines the range of the motor speed variation, is set as a performance indicator of rapid response. The proposed method is applied to both simulated data in an intermittent start-stops process and experimental data measured for a batch of servo turrets for turning lathes. The results show that the performance evaluations agree with the actual performance.

Enhanced control of DFIG wind turbine based on stator flux decay compensation

DEFF Research Database (Denmark)

Zhu, Rongwu; Deng, Fujin; Chen, Zhe

2016-01-01

For the doubly-fed induction generator (DFIG)- based wind energy conversion system (WECS), the decaying flux and negative flux are the main reasons to cause the DFIG rotor overcurrent, during grid faults. The stator decaying flux characteristics versus the depth and instant of the stator voltage...

Investigation of slot discharge on a 239 MVA hydro generator stator winding

Energy Technology Data Exchange (ETDEWEB)

Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

2009-07-01

This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

System and method for preventing stator permanent magnet demagnetization during vacuum pressure impregnation

Science.gov (United States)

Raminosoa, Tsarafidy; Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi

2017-06-06

A permanent magnet electrical machine includes a stator having conductive windings wound thereon and one or more permanent magnets embedded in the stator. A magnetic keeper element is positioned on the stator so as to form a magnetic flux path with the permanent magnets, with the magnetic keeper element closing the magnetic flux path of the permanent magnets by providing a low reluctance flux path to magnetic flux generated by the permanent magnets. A vacuum pressure impregnation (VPI) process is performed on the stator to increase a thermal conductivity of the windings, with the VPI process including a curing step that is performed at a selected temperature. The magnetic keeper element sets an operating point of the permanent magnets to an internal flux density level above a demagnetization threshold associated with the selected temperature at which the curing step is performed.

A piezoelectric ultrasonic linear micromotor using a slotted stator.

Science.gov (United States)

Yun, Cheol-Ho; Watson, Brett; Friend, James; Yeo, Leslie

2010-08-01

A novel ultrasonic micro linear motor that uses 1st longitudinal and 2nd bending modes, derived from a bartype stator with a rectangular slot cut through the stator length, has been proposed and designed for end-effect devices of microrobotics and bio-medical applications. The slot structure plays an important role in the motor design, and can be used not only to tune the resonance frequency of the two vibration modes but also to reduce the undesirable longitudinal coupling displacement caused by bending vibration at the end of the stator. By using finite element analysis, the optimal slot dimension to improve the driving tip motion was determined, resulting in the improvement of the motor performance. The trial linear motor, with a weight of 1.6 g, gave a maximum driving velocity of 1.12 m/s and a maximum driving force of 3.4 N. A maximum mechanical output power of 1.1 W was obtained at force of 1.63 N and velocity of 0.68 m/s. The output mechanical power per unit weight was 688 W/kg.

A study on the dryness judgement criterion for leak test in water-cooled generator stator windings

International Nuclear Information System (INIS)

Kim, Hee Soo; Bae, Yong Chae; Lee, Wook Ryun; Lee, Doo Young; Cho, Sung Won

2009-01-01

The complete dryness of stator inside is a necessary and sufficient condition for leak test. Microcracks by high cycle fatigue due to operation are generated in stator windings and they are interrupted by water molecules during leak test. For this reason, during leak test, the wrong value is indicated as follows: There are no leaks in stator windings. Generator manufacturers presents unique dryness judgement criteria for leak test but actually any criteria never indicate accurate dryness point for leak test. The reason is that stator winding has a complexity of structure and absence of an effective dryness equipment in power plant. In this paper, dryness judgement criterion to judge if stator winding inside is dried completely is proposed and is testified experimentally.

Patterns of the Rotor-over-Stator Rolling under Change in the Damping Components

Science.gov (United States)

Shatokhin, V. F.

2018-03-01

As experimental studies show, the rubbing of the rotor against the structure usually excites harmonics of different frequencies. In high-frequency regions, the power of the vibration signal appears to be considerable. The rotor—supports—stator system is in an unstable equilibrium state during the contact interaction between the rotor and the stator. The forces exerted on the rotor facilitate the excitation of the asynchronous rolling and its damping. The forces have been determined that facilitate the excitation of the progressive and retrograde rotor precession. The consideration of these forces in the algorithm for modeling the rotor-over-stator rolling development allows investigation of the impact of the components of the above forces on the behavior of the rotor system. The initial excitation—disturbance of the normal operation—of the rotor and subsequent unsteady oscillations of it result from sudden imbalance in the second span. The results of numerical modeling of the rubbing in the second span and the rotor-over-stator rolling upon change in the damping components of secondary (gyroscopic) components b ij ( i ≠ j) of the damping matrix are presented for the rotor on three bearing-supports considering the synergetic effect of the forces of various types exerted on the rotor. It is shown that change in one of the parameters of the excitation forces leads to ambiguity of the pattern (manifestation form) of the asynchronous rotor-over-stator rolling and proves the existence of more than one states towards which the rotor—supports—stator system tends. In addition to the rolling with a constant rotor—stator contact, oscillations of the rotor develop in the direction perpendicular to the common trajectory of the precession motion of the rotor's center with transition to the vibro-impact motion mode. The oscillations of the rotor tend towards the symmetry center of the system (the stator bore center). The reason is the components of the stiffness

Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

Directory of Open Access Journals (Sweden)

Xinhua Guo

2016-07-01

Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

Epoxy Adhesives for Stator Magnet Assembly in Stirling Radioisotope Generators (SRG)

Science.gov (United States)

Cater, George M.

2004-01-01

As NASA seeks to fulfill its goals of exploration and understanding through missions planned to visit the moons of Saturn and beyond, a number of challenges arise from the idea of deep space flight. One of the first problems associated with deep space travel is electrical power production for systems on the spacecraft. Conventional methods such as solar power are not practical because efficiency decreases substantially as the craft moves away from the Sun. The criterion for power generation during deep space missions are very specific, the main points requiring high reliability, low mass, minimal vibration and a long lifespan. A Stirling generator, although fairly old in concept, is considered to be a potential solution for electrical power generation for deep space flight. A Stirling generator works on the same electromagnetic principles of a standard generator, using the linear motion of the alternator through the stationary stator which produces electric induction. The motion of the alternator, however, is produced by the heating and cooling dynamics of pressurized gases. Essentially heating one end and cooling another of a contained gas will cause a periodic expansion and compression of the gas from one side to the other, which a displacer translates into linear mechanical motion. NASA needs to confirm that the materials used in the generator will be able to withstand the rigors of space and the life expectancy of the mission. I am working on the verification of the epoxy adhesives used to bond magnets to the steel lamination stack to complete the stator; in terms of in-service performance and durability under various space environments. Understanding the proper curing conditions, high temperature properties, and degassing problems as well as production difficulties are crucial to the long term success of the generator. system and steel substrate used in the stator. To optimize the curing conditions of the epoxies, modulated differential scanning calorimetry

Magnetically induced rotor vibration in dual-stator permanent magnet motors

Science.gov (United States)

Xie, Bang; Wang, Shiyu; Wang, Yaoyao; Zhao, Zhifu; Xiu, Jie

2015-07-01

Magnetically induced vibration is a major concern in permanent magnet (PM) motors, which is especially true for dual-stator motors. This work develops a two-dimensional model of the rotor by using energy method, and employs this model to examine the rigid- and elastic-body vibrations induced by the inner stator tooth passage force and that by the outer. The analytical results imply that there exist three typical vibration modes. Their presence or absence depends on the combination of magnet/slot, force's frequency and amplitude, the relative position between two stators, and other structural parameters. The combination and relative position affect these modes via altering the force phase. The predicted results are verified by magnetic force wave analysis by finite element method (FEM) and comparison with the existing results. Potential directions are also given with the anticipation of bringing forth more interesting and useful findings. As an engineering application, the magnetically induced vibration can be first reduced via the combination and then a suitable relative position.

Numerical Simulation of Fluid Flow in a Simple Rotor/Stator Pair

Science.gov (United States)

1991-06-01

describes a series of numerical experiments dealing with rotor/stator interactions in hydroturbines . The means of analysis was a nonconforming sliding...science and industry is the improvement of the efficiency of the hydroturbine . Numerical flow analysis is essential in order to properly conduct this...evaluation. The hydroturbine is typically modeled as an infinite series of rotor/stator pairs. Figure 1 is an illustration of an axial-flow machine with

Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

Directory of Open Access Journals (Sweden)

Anna E. Frost

2017-11-01

Full Text Available This paper presents a study on how the power absorption and damping in a linear generator for wave energy conversion are affected by partial overlap between stator and translator. The theoretical study shows that the electrical power as well as the damping coefficient change quadratically with partial stator overlap, if inductance, friction and iron losses are assumed independent of partial stator overlap or can be neglected. Results from onshore experiments on a linear generator for wave energy conversion cannot reject the quadratic relationship. Measurements were done on the inductance of the linear generator and no dependence on partial stator overlap could be found. Simulations of the wave energy converter’s operation in high waves show that entirely neglecting partial stator overlap will overestimate the energy yield and underestimate the peak forces in the line between the buoy and the generator. The difference between assuming a linear relationship instead of a quadratic relationship is visible but small in the energy yield in the simulation. Since the theoretical deduction suggests a quadratic relationship, this is advisable to use during modeling. However, a linear assumption could be seen as an acceptable simplification when modeling since other relationships can be computationally costly.

Method Of Wire Insertion For Electric Machine Stators

Science.gov (United States)

Brown, David L; Stabel, Gerald R; Lawrence, Robert Anthony

2005-02-08

A method of inserting coils in slots of a stator is provided. The method includes interleaving a first set of first phase windings and a first set of second phase windings on an insertion tool. The method also includes activating the insertion tool to radially insert the first set of first phase windings and the first set of second phase windings in the slots of the stator. In one embodiment, interleaving the first set of first phase windings and the first set of second phase windings on the insertion tool includes forming the first set of first phase windings in first phase openings defined in the insertion tool, and forming the first set of second phase windings in second phase openings defined in the insertion tool.

Compressor Stator Time-Variant Aerodynamic Response to Upstream Rotor Wakes.

Science.gov (United States)

1976-11-01

periodic varia t i ons in pressure , velocity and flow direction in the exit field of an upstream element , wh i ch appea r as temporall y vary ing in a...compressor features blad i ng (42 rotor blades and 40 stator vanes , NACA 65 F Series ) that is aerodynamicall y l oaded to levels that are typical of...measurements were accom- — p lished by instrumenting a pair of the NACA Series 65 stator — vanes with flush mounted Ku lite thin -line des i gn dynamic

Systematic modeling for free stators of rotary - Piezoelectric ultrasonic motors

DEFF Research Database (Denmark)

Mojallali, Hamed; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

2007-01-01

An equivalent circuit model with complex elements is presented in this paper to describe the free stator model of traveling wave piezoelectric motors. The mechanical, dielectric and piezoelectric losses associated with the vibrator are considered by introducing the imaginary part to the equivalent...... circuit elements. The determination of the complex circuit elements is performed by using a new simple iterative method. The presented method uses information about five points of the stator admittance measurements. The accuracy of the model in fitting to the experimental data is verified by using...

System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

Science.gov (United States)

Lu, Bin [Kenosha, WI; Luebke, Charles John [Sussex, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Becker, Scott K [Oak Creek, WI

2011-12-27

A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

An electrostatic lower stator axial gap wobble motor: design and fabrication

OpenAIRE

Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt

1995-01-01

The fabrication, initial modelling and first results of an electrostatic lower stator axial gap wobble motor are presented. The four mask fabrication process is based on polysilicon surface micromachining techniques. Three to twelve stator pole wobble motor designs have been realized with rotor radii of 50 and 100 micrometer. A theoretical model predicts torque generations in the nNm range at high electrostatic fields. Motors have typically been operated between 10 and 20 Volts. Initial exper...

Partial discharge as a stator winding evaluation tool

International Nuclear Information System (INIS)

Maughan, C.V.

2005-01-01

This paper has been prepared to illustrate the value of partial discharge (PD) testing in assessing the condition of stator windings on operating generators and motors. The database of one particular PD system vendor was chosen for this study because of the magnitude of data accumulated by this company over the last 15 years. It was felt that sufficient data had been accumulated to allow useful statistical analysis of the capabilities of PD testing. The PD detection technology used by Iris has been installed on about 6000 generators and motors, and has inspection information from about 3600 machines. On these 3600 generators and motors, PD has successfully identified 209 potential problems that were verified by inspection to be present. In most cases, moderate corrective maintenance permitted return of the equipment to service without major repairs. An estimate of the actual number of avoided failures was not possible from the available reports. But it is clear that many potentially serious stator winding failures were avoided as a result of removal of these machines from service because of high PD readings. No attempt has been made in the paper to provide technical background or details of the PD test/analysis processes. There are numerous technical papers and industry guides; the interested reader is referred to IEEE 1434, EPRI Reports, and other documents in the Bibliography. While this paper is based somewhat narrowly on data from only one company, there are several other companies involved in PD testing and evaluation. As described below in this paper, these companies have also been successful in identifying stator winding problems through the use of PD equipment. Clearly, PD testing is a useful tool in monitoring and assessing the condition of stator windings, as well as other associated electrical equipment in the power plant. Because of the power of PD testing, it is expected that the use of PD monitoring will continue to expand at a significant rate in

Investigation of a tubular dual-stator flux-switching permanent-magnet linear generator for free-piston energy converter

Science.gov (United States)

Sui, Yi; Zheng, Ping; Tong, Chengde; Yu, Bin; Zhu, Shaohong; Zhu, Jianguo

2015-05-01

This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover.

A High Torque Density Axial Flux SRM with Modular Stator

Directory of Open Access Journals (Sweden)

Y Ebrahimi

2015-12-01

Full Text Available A novel structure of switched reluctance motors (SRMs is proposed. The proposed structure uses the benefits of the axial flux path, short flux path, segmental rotor, and flux reversal free stator motors all together to improve the torque density of the SRMs. The main geometrical, electrical and physical specifications are presented. In addition, some features of the proposed structure are compared with those of a state-of-the-art radial flux SRM, considered as a reference motor. Then, the proposed structure is modified by employing a higher number of rotor segments than the stator modules and at the same time, reshaped stator modules tips. Achieved results reveal that, compared with the reference motor, the proposed and the modified proposed motors deliver about the same torque with 36.5% and 46.7% lower active material mass, respectively. The efficiency and torque production capability for the extended current densities are also retained. These make the proposed structures a potentially proper candidate for the electric vehicles (EVs and hybrid electric vehicles (HEVs as an in-wheel motor.

Vibration monitoring of large generator stator and-winding

International Nuclear Information System (INIS)

Duffeau, F.; Bernard, P.

1999-01-01

Large generators of French Nuclear Power plants are equipped with a standardised vibration monitoring system. The first aim of these new systems is to protect the machines by generating alarms in the control room when predefined vibration thresholds have been over-passed. Secondly, this specially designed instrumentation permits to create a National data base allowing to compare different generators of the same technology. Additionally, statistical methods have been developed in order to 'guess' vibration level at several locations of the stator end-windings, depending on the actual operating parameters of the generator, i.e. reactive and active power load. So this paper presents the general concept of the vibration monitoring of EDF large generator stators and deals with a new method to predict vibrations in different locations under control. (authors)

Digital signal processing control of induction machine`s torque and stator flux utilizing the direct stator flux field orientation method

Energy Technology Data Exchange (ETDEWEB)

Seiz, Julie Burger [Union College, Schenectady, NY (United States)

1997-04-01

This paper presents a review of the Direct Stator Flux Field Orientation control method. This method can be used to control an induction motor`s torque and flux directly and is the application of interest for this thesis. This control method is implemented without the traditional feedback loops and associated hardware. Predictions are made, by mathematical calculations, of the stator voltage vector. The voltage vector is determined twice a switching period. The switching period is fixed throughout the analysis. The three phase inverter duty cycle necessary to control the torque and flux of the induction machine is determined by the voltage space vector Pulse Width Modulation (PWM) technique. Transient performance of either the flux or torque requires an alternate modulation scheme which is also addressed in this thesis. A block diagram of this closed loop system is provided. 22 figs., 7 tabs.

Control System for Producing Electricity with Dual Stator Winding Cage-Rotor Induction Generator

Directory of Open Access Journals (Sweden)

Lucian Nicolae Tutelea

2014-09-01

Full Text Available This paper will present the key design equations and control design model of the Dual Stator Winding Cage-Rotor Induction Generator (DSWIG to achieve wide-speed-range operation with reduced capacity of the static power controller for low power wind or hydro applications. The proposed induction generator consists of a standard squirrel-cage rotor and a stator with two separate windings wound for a similar number of poles. Moreover, the system control strategy using the stator flux orientation is consequently proposed. The aim of the paper is to emphasize that the low speed induction generators with power electronic converters represent a realistic and useful solution for direct drive power applications.

A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

OpenAIRE

Jing Zhao; Yun Zheng; Congcong Zhu; Xiangdong Liu; Bin Li

2017-01-01

A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM) motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSP...

Stator and Rotor Faults Diagnosis of Squirrel Cage Motor Based on Fundamental Component Extraction Method

Directory of Open Access Journals (Sweden)

Guoqing An

2017-01-01

Full Text Available Nowadays, stator current analysis used for detecting the incipient fault in squirrel cage motor has received much attention. However, in the case of interturn short circuit in stator, the traditional symmetrical component method has lost the precondition due to the harmonics and noise; the negative sequence component (NSC is hard to be obtained accurately. For broken rotor bars, the new added fault feature blanked by fundamental component is also difficult to be discriminated in the current spectrum. To solve the above problems, a fundamental component extraction (FCE method is proposed in this paper. On one hand, via the antisynchronous speed coordinate (ASC transformation, NSC of extracted signals is transformed into the DC value. The amplitude of synthetic vector of NSC is used to evaluate the severity of stator fault. On the other hand, the extracted fundamental component can be filtered out to make the rotor fault feature emerge from the stator current spectrum. Experiment results indicate that this method is feasible and effective in both interturn short circuit and broken rotor bars fault diagnosis. Furthermore, only stator currents and voltage frequency are needed to be recorded, and this method is easy to implement.

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

Energy Technology Data Exchange (ETDEWEB)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong [Inha Univ., Incheon (Korea, Republic of)

2017-01-15

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

International Nuclear Information System (INIS)

Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong

2017-01-01

In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

A finite volume method and experimental study of a stator of a piezoelectric traveling wave rotary ultrasonic motor.

Science.gov (United States)

Bolborici, V; Dawson, F P; Pugh, M C

2014-03-01

Piezoelectric traveling wave rotary ultrasonic motors are motors that generate torque by using the friction force between a piezoelectric composite ring (or disk-shaped stator) and a metallic ring (or disk-shaped rotor) when a traveling wave is excited in the stator. The motor speed is proportional to the amplitude of the traveling wave and, in order to obtain large amplitudes, the stator is excited at frequencies close to its resonance frequency. This paper presents a non-empirical partial differential equations model for the stator, which is discretized using the finite volume method. The fundamental frequency of the discretized model is computed and compared to the experimentally-measured operating frequency of the stator of Shinsei USR60 piezoelectric motor. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of induction machines with combined stator windings

Czech Academy of Sciences Publication Activity Database

Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav

2015-01-01

Roč. 60, č. 2 (2015), s. 155-171 ISSN 0001-7043 R&D Projects: GA ČR GA13-35370S Institutional support: RVO:61388998 Keywords : induction machines * symmetrical components * combined stator winding Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

On the interaction of a fan stator and acoustic treatments using the transfer element method

Energy Technology Data Exchange (ETDEWEB)

Wang Xiaoyu; Sun Xiaofeng [Fluid and Acoustic Engineering Laboratory, Beijing University of Aeroacoustics and Astronautics, Beijing 100083 (China)], E-mail: Sunxf@buaa.edu.cn

2010-02-15

In the present investigation, a theoretical model is suggested to study the interaction of a fan stator and acoustic treatments using the transfer element method. Firstly, the solution of an acoustic field caused by a fan stator in an infinite duct is extended to that in a finite domain with all knowns and unknowns on the interface plane. Secondly, the related numerical results for an annular cascade are compared with the data obtained by directly solving an integral equation based on the blade boundary condition, which have good agreement with each other. Finally, more emphasis is placed on studying how a fan stator interacts with both upstream and downstream acoustic treatments. It is found that the interaction has an important influence on sound attenuation. In addition, optimal sound attenuation will depend on the combined design of both acoustic treatment and the fan stator. (invited paper)

On the interaction of a fan stator and acoustic treatments using the transfer element method

International Nuclear Information System (INIS)

Wang Xiaoyu; Sun Xiaofeng

2010-01-01

In the present investigation, a theoretical model is suggested to study the interaction of a fan stator and acoustic treatments using the transfer element method. Firstly, the solution of an acoustic field caused by a fan stator in an infinite duct is extended to that in a finite domain with all knowns and unknowns on the interface plane. Secondly, the related numerical results for an annular cascade are compared with the data obtained by directly solving an integral equation based on the blade boundary condition, which have good agreement with each other. Finally, more emphasis is placed on studying how a fan stator interacts with both upstream and downstream acoustic treatments. It is found that the interaction has an important influence on sound attenuation. In addition, optimal sound attenuation will depend on the combined design of both acoustic treatment and the fan stator. (invited paper)

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

Energy Technology Data Exchange (ETDEWEB)

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.

A Parametric Study of Unsteady Rotor-Stator Interaction in a Simplified Francis Turbine

Science.gov (United States)

Wouden, Alex; Cimbala, John; Lewis, Bryan

2011-11-01

CFD analysis is becoming a critical stage in the design of hydroturbines. However, its capability to represent unsteady flow interactions between the rotor and stator (which requires a 360-degree, mesh-refined model of the turbine passage) is hindered. For CFD to become a more effective tool in predicting the performance of a hydroturbine, the key interactions between the rotor and stator need to be understood using current numerical methods. As a first step towards evaluating this unsteady behavior without the burden of a computationally expensive domain, the stator and Francis-type rotor blades are reduced to flat plates. Local and global variables are compared using periodic, semi-periodic, and 360-degree geometric models and various turbulence models (k-omega, k-epsilon, and Spalart-Allmaras). The computations take place within the OpenFOAM® environment and utilize a general grid interface (GGI) between the rotor and stator computational domains. The rotor computational domain is capable of dynamic rotation. The results demonstrate some of the strengths and limitations of utilizing CFD for hydroturbine analysis. These case studies will also serve as tutorials to help others learn how to use CFD for turbomachinery. This research is funded by a grant from the DOE.

Analysis of the flow field into a two stages and double entry storage pump taking into account two geometries of stator blades

International Nuclear Information System (INIS)

Dunca, G; Isbasoiu, E C; Muntean, S

2010-01-01

The paper presents the 3D numerical analysis of the flow into a hydraulic passage of the two stages and double entry storage pump. One of the reasons for choosing this machinery was that, even from the beginning of its operation, high levels of noise and vibration were recorded. According to the literature, these can be considered as effects of the impeller-stator phenomenon. After only 100 hours of operation, the pump' first stator blades was bend and the second stator blades was broken. As a rehabilitation solution, 100 mm of the chord were cut from the stator blades, near the leading edge. After the rehabilitation, a decrease of the noise and vibration levels during pump operation was observed. In order to analyse the pump behaviour, three measurements campaigns were conducted, after the rehabilitation. Yet, the experimental results were not very conclusive. A more detailed experimental analysis on a real turbo machine is very difficult and expensive. Thus, in order to obtain more detailed information regarding the impeller-stator phenomenon inside the analysed pump, a numerical analysis was realized. The impeller-stator (between the first impeller and first stator as well as between second impeller and second stator) and stator-impeller (between the first stator and second impeller) interactions are taken into account with mixing interface method. The hydrodynamic field from the inlet to the outlet is obtained. As a result, the pressure rise and hydraulic efficiency are computed at best efficiency point. These values are validated against experimental data measured into the storage pump. Comparing the numerical results obtained for the two geometries of the stators, it can be seen that they have different behaviour during the pump's operation. It can be considered that, although the same geometry modification was realized for both the stators, the effects on the flow parameters are different, only for the second stator being possible to observe a net

Analysis of Operating Performance and Three Dimensional Magnetic Field of High Voltage Induction Motors with Stator Chute

Directory of Open Access Journals (Sweden)

WANG Qing-shan

2017-06-01

Full Text Available In view of the difficulties on technology of rotor chute in high voltage induction motor，the desig method adopted stator chute structure is put forward． The mathematical model of three dimensional nonlinear transient field for solving stator chute in high voltage induction motor is set up． Through the three dimensional entity model of motor，three dimensional finite element method based on T，ψ － ψ electromagnetic potential is adopted for the analysis and calculation of stator chute in high voltage induction motor under rated condition． The distributions long axial of fundamental wave magnetic field and tooth harmonic wave magnetic field are analyzed after stator chute，and the weakening effects on main tooth harmonic magnetic field are researched． Further more，the comparison analysis of main performance parameters of chute and straight slot is carried out under rated condition． The results show that the electrical performance of stator chute is better than that of straight slot in high voltage induction motor，and the tooth harmonic has been sharply decreased

Detailed Study of Closed Stator Slots for a Direct-Driven Synchronous Permanent Magnet Linear Wave Energy Converter

Directory of Open Access Journals (Sweden)

Erik Lejerskog

2014-01-01

Full Text Available The aim of this paper is to analyze how a permanent magnet linear generator for wave power behaves when the stator slots are closed. The usual design of stator geometry is to use open slots to maintain a low magnetic leakage flux between the stator teeth. By doing this, harmonics are induced in the magnetic flux density in the air-gap due to slotting. The closed slots are designed to cause saturation, to keep the permeability low. This reduces the slot harmonics in the magnetic flux density, but will also increase the flux leakage between the stator teeth. An analytical model has been created to study the flux through the closed slots and the result compared with finite element simulations. The outcome shows a reduction of the cogging force and a reduction of the harmonics of the magnetic flux density in the air-gap. It also shows a small increase of the total magnetic flux entering the stator and an increased magnetic flux leakage through the closed slots.

Rotor-stator and disc systems for emulsification processes

Energy Technology Data Exchange (ETDEWEB)

Urban, K.; Roeglin, D.; Ulrich, J. [Martin-Luther-Universitaet Halle-Wittenberg, FB Ingenieurwissenschaften, Institut fuer Verfahrenstechnik/TVT, D-06099 Halle (Saale) (Germany); Wagner, G.; Schaffner, D. [DSM Nutritional Products AG, CH-4002 Basel (Switzerland)

2006-01-01

Emulsions now find a wide range of applications in industry and daily life. In the pharmaceutical industry lipophilic active ingredients as well as many nutritional products such as vitamins are often formulated in the dispersed phase of oil-in-water emulsions. Emulsions can be produced with different mechanical emulsification techniques. In the following review, the process of rotor-stator systems and disc systems are compared to other popular mechanical emulsification systems. On the basis of experimental results from the authors' laboratory, a discontinuous gear-rim dispersing system, discontinuous disc system, and a continuous high pressure system are compared with regard to their attainable mean droplet diameter and drop size distribution in an oil-in-water emulsion. It can be shown that dissolver discs with a very simple geometry attain very small mean droplet diameters and a very narrow droplet size distribution, comparable to the emulsions obtained with established rotor-stator systems such as gear-rim dispersers. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Simulation of Lightning Overvoltage Distribution on Stator Windings of Wind Turbine Generators

Institute of Scientific and Technical Information of China (English)

LIU Rong; LIU Xue-zhong; WANG Ying; LI Dan-dan

2011-01-01

This paper analyzes lightning surge on the stator windings of wind turbine generators. The path of lightning in the wind turbines was analyzed. An equivalent circuit model for megawatt direct-driven wind turbine system was developed, in which high-frequency distributed parameters of the blade conducts, tower, power cables and stator windings of generator were calculated based on finite element method, and the models of converter, grounding, loads, surge protection devices and power grid were established. The voltage distribution along stator windings, when struck by lightning with 10/350 ~ts wave form and different amplitude current between 50 kA and 200 kA, was simulated u- sing electro-magnetic transient analysis method. The simulated results show that the highest coil-to-core voltage peak appears on the last coil or near the neutral of stator windings, and the voltage distribution along the windings is non- uniform initially. The voltage drops of each coil fall from first to last coil, and the highest voltage drop appears on the first coil. The insulation damage may occur on the windings under lightning overvoltage. The surge arresters can re- strain the lightning surge in effect and protect the insulation. The coil-to-core voltage in the end of windings is nearly 19.5 kV under the 200 kA lightning current without surge arresters on the terminal of generator, but is only 2.7 kV with arresters.

Simulation of unsteady flows through stator and rotor blades of a gas turbine using the Chimera method

Science.gov (United States)

Nakamura, S.; Scott, J. N.

1993-01-01

A two-dimensional model to solve compressible Navier-Stokes equations for the flow through stator and rotor blades of a turbine is developed. The flow domains for the stator and rotor blades are coupled by the Chimera method that makes grid generation easy and enhances accuracy because the area of the grid that have high turning of grid lines or high skewness can be eliminated from the computational domain after the grids are generated. The results of flow computations show various important features of unsteady flows including the acoustic waves interacting with boundary layers, Karman vortex shedding from the trailing edge of the stator blades, pulsating incoming flow to a rotor blade from passing stator blades, and flow separation from both suction and pressure sides of the rotor blades.

Modeling and Analysis of Double Stator Slotted Rotor Permanent Magnet Generator

Directory of Open Access Journals (Sweden)

Suhairi Rizuan Che Ahmad

2017-03-01

Full Text Available This paper discusses the modeling and analysis of three phase double stator slotted rotor permanent magnet generator (DSSR-PMG. The use of double stator topology through the double magnetic circuit helps to maximize the usage of flux linkage in the yoke structure of the single stator topology. The analytical computation is done using Permeance Analysis Method (PAM. Finite Element Analysis (FEA is used for numerical verifications and to verify the design structure a prototype laboratory is performed. The analysis is done with various loading conditions to derive the electromagnetic torque, output power and efficiency for the proposed structure. The analytical, numerical and experimental results from the analysis are found to be in good agreement. The maximum power developed by this generator at rated speed of 2000 rpm is of 1 kW with the operational efficiency of 75%. A rectifier bridge circuit is used to make the generated voltage a storage capable constant voltage to make it suitable for mobile applications (such as Direct Current DC generator. The proposed generator structure is highly recommended for applications such as micro-hydro and small renewable plants.

Speed of the bacterial flagellar motor near zero load depends on the number of stator units.

Science.gov (United States)

Nord, Ashley L; Sowa, Yoshiyuki; Steel, Bradley C; Lo, Chien-Jung; Berry, Richard M

2017-10-31

The bacterial flagellar motor (BFM) rotates hundreds of times per second to propel bacteria driven by an electrochemical ion gradient. The motor consists of a rotor 50 nm in diameter surrounded by up to 11 ion-conducting stator units, which exchange between motors and a membrane-bound pool. Measurements of the torque-speed relationship guide the development of models of the motor mechanism. In contrast to previous reports that speed near zero torque is independent of the number of stator units, we observe multiple speeds that we attribute to different numbers of units near zero torque in both Na + - and H + -driven motors. We measure the full torque-speed relationship of one and two H + units in Escherichia coli by selecting the number of H + units and controlling the number of Na + units in hybrid motors. These experiments confirm that speed near zero torque in H + -driven motors increases with the stator number. We also measured 75 torque-speed curves for Na + -driven chimeric motors at different ion-motive force and stator number. Torque and speed were proportional to ion-motive force and number of stator units at all loads, allowing all 77 measured torque-speed curves to be collapsed onto a single curve by simple rescaling. Published under the PNAS license.

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

International Nuclear Information System (INIS)

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

Dual stator winding variable speed asynchronous generator: optimal design and experiments

International Nuclear Information System (INIS)

Tutelea, L N; Deaconu, S I; Popa, G N

2015-01-01

In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA]. (paper)

A Very Low-Speed Sensorless Induction Motor Drive with Online Stator Resistance identification scheme

Directory of Open Access Journals (Sweden)

M. Zaky

2008-03-01

Full Text Available Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at low speed.

Optimal Design of Stator Interior Permanent Magnet Machine with Minimized Cogging Torque for Wind Power Application

DEFF Research Database (Denmark)

Chen, Zhe; Zhang, Jianzhong; Cheng, Ming

2008-01-01

This paper proposes a new approach to minimize the cogging torque of a stator interior permanent magnet (SIPM) machine. The optimization of stator slot gap and permanent magnet is carried out and the cogging torque ripple is analyzed by using finite element analysis. Experiments on a prototype...

Rotational hysteresis and eddy current losses in electrical motor stators under non-conventional supply

International Nuclear Information System (INIS)

Bottauscio, Oriano.; Canova, Aldo; Chiampi, Mario; Repetto, Maurizio

2003-01-01

The magnetic analysis of stators of electrical motors is performed through an innovative 2D finite element formulation that takes into account the effects of eddy currents within the laminations by means of a generalized constitutive relationship also including vector hysteresis. This approach is applied to a deep estimation of magnetic flux distribution and magnetic losses in stator of induction motors supplied by high-frequency sinusoidal or six-step voltage sources

Free Stator Modeling of a Traveling Wave Ultrasonic Motor

DEFF Research Database (Denmark)

Izadi-Zamanabadi, Roozbeh; Helbo, Jan; Mojallali, Hamed

2005-01-01

An equivalent circuit method describing the free stator of piezoelectric motor is presented in this paper, while the circuit elements have complex values. The mechanical, dielectric and piezoelectric losses associated with the vibrator are accounted for by the imaginary components of the circuit ...

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

Directory of Open Access Journals (Sweden)

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.

Calculation and analysis of generator limiting regimes with respect to stator end core heating

Directory of Open Access Journals (Sweden)

Kostić Miloje

2015-01-01

Full Text Available A new simplified procedure for defining the limiting operating regimes on the generator capability curve, with respect to stator end core heating, is proposed and described in this paper. First of all, a simplified analysis of axial flux leakage that penetrates into the end plates of the stator is carried out and the corresponding power losses are calculated. Then the analysis of measured point temperature increases over the stator end core, and a qualitative and quantitative overview of the effects, are presented. A simplified procedure for defining the limiting regime with regard to the heating stator end core, which is illustrated for the case of an operating diagram for a given generator of apparent power of 727 MVA (B2 is also described. The given limiting line constructed using this method is similar to the appropriate line constructed on the basis of complex and lengthy factory and on-site tests performed by the manufacturer and the user. According to the results and the check, the proposed method has been proved and the application of the simplified procedure can be recommended for use along with other procedures, at least when it comes to similar synchronous generators in Serbia's Electric Power Industry.

Detection of Stator Winding Fault in Induction Motor Using Fuzzy Logic with Optimal Rules

Directory of Open Access Journals (Sweden)

Hamid Fekri Azgomi

2013-04-01

Full Text Available Induction motors are critical components in many industrial processes. Therefore, swift, precise and reliable monitoring and fault detection systems are required to prevent any further damages. The online monitoring of induction motors has been becoming increasingly important. The main difficulty in this task is the lack of an accurate analytical model to describe a faulty motor. A fuzzy logic approach may help to diagnose traction motor faults. This paper presents a simple method for the detection of stator winding faults (which make up 38% of induction motor failures based on monitoring the line/terminal current amplitudes. In this method, fuzzy logic is used to make decisions about the stator motor condition. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The motor condition is described using linguistic variables. Fuzzy subsets and the corresponding membership functions describe stator current amplitudes. A knowledge base, comprising rule and data bases, is built to support the fuzzy inference. Simulation results are presented to verify the accuracy of motor’s fault detection and knowledge extraction feasibility. The preliminary results show that the proposed fuzzy approach can be used for accurate stator fault diagnosis.

A new traveling wave ultrasonic motor using thick ring stator with nested PZT excitation.

Science.gov (United States)

Chen, Weishan; Shi, Shengjun; Liu, Yingxiang; Li, Pei

2010-05-01

To avoid the disadvantages of conventional traveling wave ultrasonic motors--lower efficiency PZT working mode of d(31), fragility of the PZT element under strong excitation, fatigue of the adhesive layer under harsh environmental conditions, and low volume of the PZT material in the stator--a new type of traveling wave ultrasonic motor is presented in this paper. Here we implement the stator by nesting 64 PZT stacks in 64 slots specifically cut in a thick metal ring and 64 block springs nested within another 64 slots to produce preloading on the PZT stacks. In this new design, the d33 mode of the PZT is used to excite the flexural vibrations of the stator, and fragility of the PZT ceramics and fatigue of the adhesive layer are no longer an issue. The working principle, FEM simulation, fabrication, and performance measurements of a prototype motor were demonstrated to validate the proposed ideas. Typical output of the prototype motor is no-load speed of 15 rpm and maximum torque of 7.96 N x m. Further improvement will potentially enhance its features by increasing the accuracy in fabrication and adopting appropriate frictional material into the interface between the stator and the rotor.

The Combined Internal and Principal Parametric Resonances on Continuum Stator System of Asynchronous Machine

Directory of Open Access Journals (Sweden)

Baizhou Li

2014-01-01

Full Text Available With the increasing requirement of quiet electrical machines in the civil and defense industry, it is very significant and necessary to predict the vibration and noise characteristics of stator and rotor in the early conceptual phase. Therefore, the combined internal and principal parametric resonances of a stator system excited by radial electromagnetic force are presented in this paper. The stator structure is modeled as a continuum double-shell system which is loaded by a varying distributed electromagnetic load. The nonlinear dynamic equations are derived and solved by the method of multiple scales. The influences of mechanical and electromagnetic parameters on resonance characteristics are illustrated by the frequency-response curves. Furthermore, the Runge-Kutta method is adopted to numerically analyze steady-state response for the further understanding of the resonance characteristics with different parameters.

Detection of a bad mechanical adjustment of a stator through a CEPSTRALE analysis method

International Nuclear Information System (INIS)

Le Reverend, D.

1985-01-01

After the failure of the stator of the CRUAS 2 nuclear power plant, a full check up was necessary before restarting the engine. In spite of examinations and repairs, a defect could remain. Thereby, an on line surveillance system is usefull, especially during the first months after start up. The ''Mecanique appliquee'' division developed a device for the surveillance of the mechanical integrity of the stator. This equipment is based on the analysis of the vibration [fr

Performance of a high-work, low-aspect-ratio turbine stator tested with a realistic inlet radial temperature gradient

Science.gov (United States)

Stabe, Roy G.; Schwab, John R.

1991-01-01

A 0.767-scale model of a turbine stator designed for the core of a high-bypass-ratio aircraft engine was tested with uniform inlet conditions and with an inlet radial temperature profile simulating engine conditions. The principal measurements were radial and circumferential surveys of stator-exit total temperature, total pressure, and flow angle. The stator-exit flow field was also computed by using a three-dimensional Navier-Stokes solver. Other than temperature, there were no apparent differences in performance due to the inlet conditions. The computed results compared quite well with the experimental results.

Isogeometric analysis and harmonic stator-rotor coupling for simulating electric machines

Science.gov (United States)

Bontinck, Zeger; Corno, Jacopo; Schöps, Sebastian; De Gersem, Herbert

2018-06-01

This work proposes Isogeometric Analysis as an alternative to classical finite elements for simulating electric machines. Through the spline-based Isogeometric discretization it is possible to parametrize the circular arcs exactly, thereby avoiding any geometrical error in the representation of the air gap where a high accuracy is mandatory. To increase the generality of the method, and to allow rotation, the rotor and the stator computational domains are constructed independently as multipatch entities. The two subdomains are then coupled using harmonic basis functions at the interface which gives rise to a saddle-point problem. The properties of Isogeometric Analysis combined with harmonic stator-rotor coupling are presented. The results and performance of the new approach are compared to the ones for a classical finite element method using a permanent magnet synchronous machine as an example.

Minimization of torque ripple in ferrite-assisted synchronous reluctance motors by using asymmetric stator

Science.gov (United States)

Xu, Meimei; Liu, Guohai; Zhao, Wenxiang; Aamir, Nazir

2018-05-01

Torque ripple is one of the important issues for ferrite assisted synchronous reluctance motors (FASRMs). In this paper, an asymmetrical stator is proposed for the FASRM to reduce its torque ripple. In the proposed FASRM, an asymmetrical stator is designed by appropriately choosing the angle of the slot-opening shift. Meanwhile, its analytical torque expressions are derived. The results show that the proposed FASRM has an effective reduction in the cogging torque, reluctance torque ripple and total torque ripple. Moreover, it is easy to implement while the average torque is not sacrificed.

System and method for determining stator winding resistance in an AC motor

Science.gov (United States)

Lu, Bin [Kenosha, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Theisen, Peter J [West Bend, WI

2011-05-31

A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

On the Rotor to Stator Contact Dynamics with Impacts and Friction - Theoretical and Experimental Study

DEFF Research Database (Denmark)

Lahriri, Said

The contact between a rotor and its stator can in some cases be considered as a serious malfunction that may lead to catastrophic failure. This major threat arises normally from full annular dry friction backward whirl and whip motion where the rotor runs and rubs at a high frequency on the inner...... of the friction coefficient behavior.......The contact between a rotor and its stator can in some cases be considered as a serious malfunction that may lead to catastrophic failure. This major threat arises normally from full annular dry friction backward whirl and whip motion where the rotor runs and rubs at a high frequency on the inner...... surface of the stator, and thereby traversing the full extent of the clearance. Normal and friction forces are exerted on the rotor at each impact and rubs. These particular forces can sustain the rotor in a persistent backward dry whirl or whip motion. In that case, the friction force plays a significant...

Model based defect detection for free stator of ultrasonic motor

DEFF Research Database (Denmark)

Amini, Rouzbeh; Mojallali, Hamed; Izadi-Zamanabadi, Roozbeh

2007-01-01

In this paper, measurements of admittance magnitude and phase are used to identify the complex values of equivalent circuit model for free stator of an ultrasonic motor. The model is used to evaluate the changes in the admittance and relative changes in the values of equivalent circuit elements. ...

Core losses of an inverter-fed permanent magnet synchronous motor with an amorphous stator core under no-load

Directory of Open Access Journals (Sweden)

Nicolas Denis

2016-05-01

Full Text Available In this paper, an interior permanent magnet synchronous motor (IPMSM with a stator core made of amorphous magnetic material (AMM is presented. The IPMSM is driven by a voltage source three-phase inverter with classical pulse width modulation (PWM control. The core losses under no-load condition are measured by experiment and compared to an equivalent IPMSM with a stator core made of NO steel. Under these conditions, the core losses are influenced by the stator, rotor and magnet shapes but also by the PWM carrier signal that implies a high frequency harmonic in the magnetic flux density. It is demonstrated that the AMM can reduce the core losses by about 56 %.

Transportation of a Spare Stator to Trillo I NPP

International Nuclear Information System (INIS)

Nova, J.R. de; Sanchez Miro, J.L.; Alvaro, C. de

1998-01-01

The shutdown of Trillo NPP due to an irreparable in situ fault in the stator of the electric generator, has resulted in the need to transport a spare stator from Mulheim (Germany) to Trillo I NPP (Spain). The problem occasioned by this type of transport have been exacerbated by the very short period of time available to plan and carry out this operation. Owing to this pressing need, the logistics of the transport were tackled from all possible alternative approaches. Within each one of these alternatives, all available modes were considered, so as to minimise the possibility of an insurmountable difficulty arising and thus making it impossible to continue with trans transportation. The two basic alternatives considered were road and rail. This paper describes the different aspects which intervened in this special transport, especially the following: - The very short time period available for planning and execution - The railway transport mode used - The large number of organisations participating in the operation - The solution to the technical problems caused by the use of different types of transportation equipment - The studies, adaptations and improvements carried out on the different routes - The coordination of the resources used in the operation. (Author)

Stator Current Harmonic Control with Resonant Controller for Doubly Fed Induction Generator

DEFF Research Database (Denmark)

Liu, Changjin; Blaabjerg, Frede; Chen, Wenjie

2012-01-01

rotor current control loop for harmonic suppression. The overall control scheme is implemented in dq frame. Based on a mathematical model of the DFIG control system, the effects on system stability using the resonant controller, an analysis of the steady-state error, and the dynamic performance......, are discussed in this paper. Taking these effects into account, the parameters of the resonant controller can be designed and effectively damp the influence from the grid voltage harmonics. As a result, the impacts of the negative sequence fifth- and positive sequence seventh-order voltage harmonics...... harmonics, especially low-order harmonics. This paper proposes a stator current harmonic suppression method using a sixth-order resonant controller to eliminate negative sequence fifth- and positive sequence seventh-order current harmonics. A stator current harmonic control loop is added to the conventional...

Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator

Directory of Open Access Journals (Sweden)

Ai Mizuno

2018-02-01

Full Text Available Spherical ultrasonic motors (SUSMs that can operate with multiple degrees of freedom (MDOF using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1 increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs embedded in the stator, (2 enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3 making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y-axis and Z-axis were measured as 1.48 N∙m and 2.05 N∙m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N∙m/kg for the X(Y-axis and 1.20 N∙m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes.

Stator insulation systems for medium voltage PWM drives fed motors

International Nuclear Information System (INIS)

Gao, G.; Chen, W.

2005-01-01

This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)

Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

International Nuclear Information System (INIS)

Mellor, S.P.; Matthee, F.W.

2002-01-01

In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

Energy Technology Data Exchange (ETDEWEB)

Mellor, S.P.; Matthee, F.W. [ESKOM, Koeberg Nuclear Power Station (South Africa)

2002-07-01

In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

MRAS speed estimator with fuzzy and PI stator resistance adaptation for sensorless induction motor drives using RT-lab

Directory of Open Access Journals (Sweden)

S. Mohan Krishna

2016-09-01

Full Text Available This paper presents a real-time simulation study of Model Reference Adaptive System based rotor speed estimator with parallel stator resistance adaptation mechanism for speed sensorless induction motor drive. Both, the traditional Proportional Integral and Fuzzy logic based control mechanisms are utilised for stator resistance adaptation, while, the rotor speed is estimated parallely by means of Proportional Integral based mechanism. The estimator's response to dynamic changes in Load perturbation and doubling of the nominal value of the actual stator resistance of the motor is observed. The superiority of the fuzzy based stator resistance adaptation in the Model Reference Adaptive System estimator is proved through results validated in real-time. The purpose of employing a fairly new real-time platform is to reduce the test and prototype time. The model is initially built using Matlab/Simulink blocksets and the results are validated in real time using RT-Lab. The RT-lab blocksets are integrated into the Simulink model and then executed in real-time using the OP-4500 target developed by Opal-RT. The real-time simulation results are observed in the workstation.

A Piezoelectric Micromotor with a Stator of φ=1.6 mm and l=4 mm Using Bulk PZT

Science.gov (United States)

Cagatay, Serra; Koc, Burhanettin; Moses, Paul; Uchino, Kenji

2004-04-01

The smallest discrete piezoelectric ultrasonic motor using bulk ceramics was developed. We are proposing basically a two-part motor: stator and rotor. The stator of the present motor consists of a hollow metal brass tube with outer diameter of 1.6 mm, inner diameter of 0.8 mm and length of only 4 mm with 2 PZT plates bonded onto it. Owing to the asymmetrical stator surface, two degenerated orthogonal bending modes were slightly split, resulting in a wobbling motion. Thus, the motor can be driven by a single driving source. The rotor is a spring, which is basically different from previous designs, pressed at both ends to the stator by a pair of ferrules. Consequently, the length of the whole motor assembly was reduced significantly; a final motor length of only 5 mm was obtained. The working frequency under zero load was approximately 227-233 kHz. Although the size is small, relatively high power was obtained under an optimized load condition: torque of 0.06 mNm, maximum power of 3.2 mW with a speed of 118 rad/s, and maximum efficiency of 11% under 48 Vrms at 221 kHz.

Studying the development of asynchronous rolling of the rotor over the stator with the turbine unit protection systems having different response times

Science.gov (United States)

Shatokhin, V. F.

2014-07-01

The possibility to stabilize the developing asynchronous rolling of the rotor over the stator under the conditions of power unit protections coming in action with different response times is considered. Asynchronous rolling of the rotor over the stator may develop when the rotating rotor comes in contact with the stator at high amplitudes of vibration caused by an abrupt loss of rotor balancing, by forced or self-excited vibration of the rotor, and by other factors. The danger of asynchronous rolling is connected with almost instantaneous development of self-excited vibration of the rotor when it comes in contact with the stator and with the rotor vibration amplitudes and forces of interaction between the rotor and stator dangerous for the turbine unit integrity. It is assumed that the turbine unit protection systems come in action after the arrival of signal of exceeding the permissible vibration level and produce commands to disconnect the generator from the grid, and to stop the supply of working fluid into the flow path, due to which an accelerating torque ceases to act on the turbine unit shaft. The protection system response speed is determined by a certain time t = ABtime that is taken for its components to come in action from the commencement of the event (application of the signal) to closure of the stop valves. The time curves of the main rolling parameters as functions of the ABtime value are presented. It is shown that the response time of existing protection systems is not sufficient for efficiently damping the rolling phenomenon, although the use of an electrical protection system (with the response time equal to 0.40-0.45 s) may have a positive effect on stabilizing the vibration amplitudes to a certain extent during the rolling and on smoothing its dangerous consequences. The consequences of rotor rolling over the stator can be efficiently mitigated by increasing the energy losses in the rotor-stator system (especially in the stator) and by

P-shaped Coiled Stator Ultrasound Motor for Rotating Intravascular Surgery Device

Directory of Open Access Journals (Sweden)

Toshinobu ABE

2015-01-01

Full Text Available The primary focus of this paper is the development of an ultra-miniature ultrasound motor for use in the human blood vessel. Since the size of the drive source for rotating the atherectomy device and intravascular ultrasonography system are large currently in practical use, it is installed outside the body, and the rotational power for the atherectomy device and intravascular ultrasonography system are transmitted through the long tortuous blood vessel. Such systems suffer from the problem that the rotation becomes non-uniform, and the problem that the available time is limited. We have therefore developed a P-shaped coiled stator ultrasound motor as a miniature ultrasound motor for rotating the ultrasound sensor for use in blood vessels in order to solve these problems. In this paper, we describe measurement of the torque, revolution speed, output power, efficiency, and particle motion on acoustic waveguide of the P-shaped coiled stator ultrasound motor.

Design and Comparison of a Novel Stator Interior Permanent Magnet Generator for Direct-Drive Wind Turbines

DEFF Research Database (Denmark)

Zhang, Johan Xi; Chen, Zhe; Cheng, M.

2007-01-01

A novel stator interior permanent magnet generator (SIPMG) is presented. A modular stator design is used for convenience in manufacture and maintenance. The generator has the advantages of rugged rotor and concentrated winding design whereas the torque ripple is smaller than that produced...... by a doubly salient machine. Several low-speed multi-pole SIPMGs are designed for direct-drive wind turbines with ratings from 3 to 10 MW. Comparisons between the SIPMG and rotor-surface-mounted permanent magnet synchronous generator (PMSG) show that the SIPMGs have about 120% torque density and 78% cost per...

The reflection of evolving bearing faults in the stator current's extended park vector approach for induction machines

Science.gov (United States)

Corne, Bram; Vervisch, Bram; Derammelaere, Stijn; Knockaert, Jos; Desmet, Jan

2018-07-01

Stator current analysis has the potential of becoming the most cost-effective condition monitoring technology regarding electric rotating machinery. Since both electrical and mechanical faults are detected by inexpensive and robust current-sensors, measuring current is advantageous on other techniques such as vibration, acoustic or temperature analysis. However, this technology is struggling to breach into the market of condition monitoring as the electrical interpretation of mechanical machine-problems is highly complicated. Recently, the authors built a test-rig which facilitates the emulation of several representative mechanical faults on an 11 kW induction machine with high accuracy and reproducibility. Operating this test-rig, the stator current of the induction machine under test can be analyzed while mechanical faults are emulated. Furthermore, while emulating, the fault-severity can be manipulated adaptively under controllable environmental conditions. This creates the opportunity of examining the relation between the magnitude of the well-known current fault components and the corresponding fault-severity. This paper presents the emulation of evolving bearing faults and their reflection in the Extended Park Vector Approach for the 11 kW induction machine under test. The results confirm the strong relation between the bearing faults and the stator current fault components in both identification and fault-severity. Conclusively, stator current analysis increases reliability in the application as a complete, robust, on-line condition monitoring technology.

Robust method for stator current reconstruction from DC link in a ...

African Journals Online (AJOL)

Using the switching signals and dc link current, this paper presents a new algorithm for the reconstruction of stator currents of an inverter-fed, three-phase induction motor drive. Unlike the classical and improved methods available in literature, the proposed method is neither based on pulse width modulation pattern ...

Performance of a fractional dc electric motor equipped with plastic bonded Nd2Fe14B stator poles

International Nuclear Information System (INIS)

Nicolaides, G.K.; Atanassova, Y.K.; Ioannides, M.G.; Tsamakis, D.M.; Gamari-Seale, H.

1997-01-01

Injection molding Nd 2 Fe 14 B plastic bonded magnetic material is pressed into the form of cylindrical ring segments in order to investigate its performance when used in the manufacturing of stator poles of fractional power dc motors. Measurements of speed and armature current versus different load torques were performed. The experimental results obtained for stator poles made by three plastic bonded Nd 2 Fe 14 B magnetic materials of different densities, are compared to those results obtained by using a pair of typical barium ferrite stator poles. The torque versus speed curves, the obtained mechanical power versus speed and the efficiency of the motor as a function of the speed are presented. The torque speed data in high speeds follow a linear law, as is expected by theory, while at low speeds, below a crossover point, a deviation from this linearity appears. This is attributed to temperature effects. In this work it is shown that in the region of light loads and high speeds, at a certain speed, the injection molded Nd 2 Fe 14 B permanent magnet stators produce a higher electromagnetic torque, higher mechanical power, and higher efficiency than the barium ferrite ones. copyright 1997 American Institute of Physics

Doubly Fed Induction Generator System Resonance Active Damping through Stator Virtual Impedance

DEFF Research Database (Denmark)

Song, Yipeng; Wang, Xiongfei; Blaabjerg, Frede

2017-01-01

(positive capacitor or negative inductor) into the stator branch through stator current feedforward control. The effectiveness of the DFIG system active damping control is verified by a 7.5 kW experimental down-scaled DFIG system, and simulation results of a commercial 2 MW DFIG system is provided as well....... converters/loads. This paper analyzes and explains first the HFR phenomenon between the DFIG system and a parallel compensated weak network (series RL + shunt C). Then on the basis of the DFIG system impedance modeling, an active damping control strategy is introduced by inserting a virtual impedance...... Frequency Resonance (HFR) due to the impedance interaction between the DFIG system and the weak grid network whose impedance is comparative large. Thus, it is important to implement an active damping for the HFR in order to ensure a safe and reliable operation of both the DFIG system and the grid connected...

First electrical tests on a machine with an AC superconducting stator winding

International Nuclear Information System (INIS)

Brunet, Y.; Tixador, P.; Laumond, Y.; Sabrie, J.L.

1988-01-01

A three phase superconducting stator winding has been built using a low losses NbTi wire under 50 Hz varying magnetic field and current. It has first been necessary to design an horizontal helium cryostat with fiber-glass composites to avoid the permanent eddy-current losses of the rotating magnetic fields. The liquid helium vessel, containing the armature, is dismountable. The cryostat is 900 mm long and the rotor bore has a diameter of 180 mm. The windings are wounded on five concentric fiber glass cylinders with a thin impregnation of an epoxy film adhesive. The first electrical tests have been performed using a normal iron rotor inside the superconducting stator. No load and permanent tests have been achieved up to a power of 13 kVA. The 18,5 kVA predicted have not been reached because of the present inductor, not yet superconducting

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

Directory of Open Access Journals (Sweden)

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.

Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives

Science.gov (United States)

Farina, Francesco; Bojoi, Radu; Tenconi, Alberto; Profumo, Francesco

A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

Sensorless Stator Field-Oriented Controlled IM Drive at Low Speed with Rr Estimator

Directory of Open Access Journals (Sweden)

Wen-Cheng Pu

2014-01-01

Full Text Available This paper pertains to a technique of a sensorless indirect stator field-oriented induction motor control, which prevents the accumulative errors incurred by the integrator and the problem relating to the stability of the control system caused by the stator resistance susceptible to temperature variations while conducting the flux estimation directly and computing the synchronous rotary speed. The research adds an adaptive flux observer to estimate the speed of the rotor and uses the fixed trace algorithm (FTA to execute an online estimation of the slip difference, thereby improving the system of stability under the low rotary speed at regenerating mode and the influence of the rotor resistance on the slip angle. Finally, the paper conducts simulations by Simulink of MATLAB and practices to verify the correctness of the result the paper presents.

A bio-hybrid DNA rotor-stator nanoengine that moves along predefined tracks.

Science.gov (United States)

Valero, Julián; Pal, Nibedita; Dhakal, Soma; Walter, Nils G; Famulok, Michael

2018-06-01

Biological motors are highly complex protein assemblies that generate linear or rotary motion, powered by chemical energy. Synthetic motors based on DNA nanostructures, bio-hybrid designs or synthetic organic chemistry have been assembled. However, unidirectionally rotating biomimetic wheel motors with rotor-stator units that consume chemical energy are elusive. Here, we report a bio-hybrid nanoengine consisting of a catalytic stator that unidirectionally rotates an interlocked DNA wheel, powered by NTP hydrolysis. The engine consists of an engineered T7 RNA polymerase (T7RNAP-ZIF) attached to a dsDNA nanoring that is catenated to a rigid rotating dsDNA wheel. The wheel motor produces long, repetitive RNA transcripts that remain attached to the engine and are used to guide its movement along predefined ssDNA tracks arranged on a DNA nanotube. The simplicity of the design renders this walking nanoengine adaptable to other biological nanoarchitectures, facilitating the construction of complex bio-hybrid structures that achieve NTP-driven locomotion.

Influence of upstream stator on rotor flutter stability in a low pressure steam turbine stage

Energy Technology Data Exchange (ETDEWEB)

Huang, X.; He, L. [University of Durham (United Kingdom). School of Engineering; Bell, D. [ALSTOM Power Ltd., Rugby (United Kingdom)

2006-07-01

Conventional blade flutter prediction is normally based on an isolated blade row model, however, little is known about the influence of adjacent blade rows. In this article, an investigation is presented into the influence of the upstream stator row on the aero-elastic stability of rotor blades in the last stage of a low pressure (LP) steam turbine. The influence of the upstream blade row is computed directly by a time-marching, unsteady, Navier-Stokes flow solver in a stator-rotor coupled computational domain. The three-dimensional flutter solution is obtained, with adequate mesh resolution, in a single passage domain through application of the Fourier-Transform based Shape-Correction method. The capability of this single-passage method is examined through comparison with predictions obtained from a complete annulus model, and the results demonstrate a good level of accuracy, while achieving a speed up factor of 25. The present work shows that the upstream stator blade row can significantly change the aero-elastic behaviour of an LP steam turbine rotor. Caution is, therefore, advised when using an isolated blade row model for blade flutter prediction. The results presented also indicated that the intra-row interaction is of a strong three-dimensional nature. (author)

Investigation of Stator and Rotor Slits’ Effects to the Torque and Efficiency of an Induction Motor

Directory of Open Access Journals (Sweden)

Serdal ARSLAN

2017-02-01

Full Text Available Induction machines have a simple structure and are popular due to their wide range of use, however they have limited power factor and efficiency. Although the working principles of inductions machines have not changed for years, the materials and geometric structures used have undergone significant changes. In this study, slits were applied in the middle of the rotor teeth, rotor-stator teeth and stator teeth of a 7.5 kW induction motor. For these three situations, the torque ripple, iron losses, copper losses, inductance, phase current and voltage inducted in the windings and flux change were analyzed associated with the change in the slit width and slit height. Due to the fact that it is difficult to analytically calculate the slitted models created, they were analyzed by software which uses the finite elements method. The stator-rotor slitted structure determined as the optimum (the one with highest efficiency and the original motor were compared with 2D and 3D analyses. According to this comparison, a decrease in torque rupture and loss of copper is observed. The motor’s torque increased by 27%, and efficiency increased by 4%.

Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring

Science.gov (United States)

Bazzo, João Paulo; Pipa, Daniel Rodrigues; da Silva, Erlon Vagner; Martelli, Cicero; Cardozo da Silva, Jean Carlos

2016-01-01

This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS) and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure. PMID:27618040

Synthesis and Investigation of Algorithm for Estimation of Active Stator Resistance of Asynchronous Motor with Fixed Rotor

Directory of Open Access Journals (Sweden)

D. S. Odnolko

2012-01-01

Full Text Available The paper proposes an algorithm for online identification of active stator resistance. Algorithm synthesis has been developed on the basis of a recursive least squares method. The problem has been solved for induction motor model defined in the stationary stator frame α–β-coordinating system. An analysis of negative factors deteriorating the identifier operation has been made in the paper. The analysis has revealed the following: measured signals are noisy due to quantization and differentiation; dynamic model of an induction motor provides only approximate presentation about actual processes in the electromagnetic system of the machine. The paper presents results of  a system simulation while applying the proposed algorithm that confirm the fact that the estimated value of the active stator resistance tends to a true value with high accuracy. The identification test assumes a fixed rotor and nominal parameters uncertainty, but the flexible structure of the algorithm allows to use it as  for single-phase excitation so for full-phase control of the induction motor with freely rotating motor.

Presentation and Performance Evaluation of a Novel Stator-Permanent-Magnet Hybrid Stepping Motor

Directory of Open Access Journals (Sweden)

Binglin Lu

2017-05-01

Full Text Available In this paper, a new type of hybrid stepping motor (HSM with permanent magnets (PMs embedded in the stator, namely the stator-permanent-magnet hybrid stepping motor (SHSM, is presented. It has the same operation principles as the traditional HSM, with a 2-D distributed magnetic field nature and superiorities such as simpler rotor structure, easier PM cooling, higher torque and power density, and higher power grade. Its structural topology and operation principles are initially presented. Then an investigation on the performance comparison between the HSM and the SHSM, in terms of PM flux density, PM torque, detent torque, positional holding accuracy, stator core saturation issue, PM flux leakage, and PM utilization rate is carried out theoretically to make an assessment of the performance superiorities of the SHSM. A prototype of a 2-phase 8-pole 50-rotor-tooth SHSM is fabricated and experimentally compared with the HSM by using finite element analysis (FEA to verify the motor’s operational feasibility and the theoretical analysis. The FEA and experimental results show that the proposed SHSM has performance advantages such as higher torque density, higher power grade, and higher pull-out torque, holding torque, and torque-speed property, although it has performance defects such as higher torque ripple and relatively lower positional holding accuracy in the open-loop operation than the conventional HSM. Consequently, this novel SHSM is more suitable for electromechanical energy conversion applications rather than positioning mechanisms, especially taking into account the open-loop control advantage.

Bearing failure detection of micro wind turbine via power spectral density analysis for stator current signals spectrum

Science.gov (United States)

Mahmood, Faleh H.; Kadhim, Hussein T.; Resen, Ali K.; Shaban, Auday H.

2018-05-01

The failure such as air gap weirdness, rubbing, and scrapping between stator and rotor generator arise unavoidably and may cause extremely terrible results for a wind turbine. Therefore, we should pay more attention to detect and identify its cause-bearing failure in wind turbine to improve the operational reliability. The current paper tends to use of power spectral density analysis method of detecting internal race and external race bearing failure in micro wind turbine by estimation stator current signal of the generator. The failure detector method shows that it is well suited and effective for bearing failure detection.

Comparison of stator-mounted permanent-magnet machines based on a general power equation

DEFF Research Database (Denmark)

Chen, Zhe; Hua, Wei; Cheng, Ming

2009-01-01

The stator-mounted permanent-magnet (SMPM) machines have some advantages compared with its counterparts, such as simple rotor, short winding terminals, and good thermal dissipation conditions for magnets. In this paper, a general power equation for three types of SMPM machine is introduced first...

Project of Economically Profitable Technological Process of Production of Rotor and Stator Plates of Inductive Position Sensor by Blanking and Roll Bending

Directory of Open Access Journals (Sweden)

Radek ČADA

2013-12-01

Full Text Available Paper concerns innovation of production of rotor and stator plates of inductive position sensors which are used at automatization of production processes. Authors analyse possibility of efficiency improvement of production of these devices in joint-stock company TES VSETÍN and suggest concrete solving of new production technology. Composition of production line for blanking and roll bending of rotor and stator plates of inductive position sensor from individual technological devices was suggested: decoiler, straightening device, actuating belt feeder, pneumatic shears with inclined tools, belt conveyer and four cylinders bending rolls. Construction of production line was projected in order to its operation can be secured by one production workman, which controls and chooses operation of CNC programme, takes separate roll bended rotor and stator plates of inductive position sensor from bending rolls and according to required technological procedure he composes them to rotor and stator complexes. Construction of production line was projected so that it is possible to move it by crane without necessity to dismantle and subsequently to put together and adjust the line.

The impact of different stator and rotor slot number combinations on iron losses of a three-phase induction motor at no-load

International Nuclear Information System (INIS)

Marcic, T.; Stumberger, B.; Stumberger, G.; Hadziselimovic, M.; Zagradisnik, I.

2008-01-01

The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots

Decrease in the damage of powerful turbogenerator stator caused by vibration in the end zones (analysis, hypotheses, experiment

Directory of Open Access Journals (Sweden)

Yu.A. Shumilov

2014-03-01

Full Text Available The analysis of the turbogenerators’ TВВ-1000-2Y3 failure has shown that the most vulnerable link in the stator is such of their elements as tightening prisms, the teeth of the end packet core, lead-out and connecting buses of the stator winding. The basic reason for the destruction of the elements mentioned is metal fatigue caused by excessive vibration under the influence of variable axial forces of electromagnetic origin. Preventing the destruction of the structural elements may be achieved by vibration monitoring and diagnostics.

Analysis of Properties of Induction Machine with Combined Parallel Star-Delta Stator Winding

Czech Academy of Sciences Publication Activity Database

Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav

2017-01-01

Roč. 113, č. 1 (2017), s. 147-153 ISSN 0239-3646 R&D Projects: GA ČR(CZ) GA16-07795S Institutional support: RVO:61388998 Keywords : induction machine * parallel combined stator winding Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering

Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

Directory of Open Access Journals (Sweden)

Mohachiro Oka

2018-04-01

Full Text Available Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

Science.gov (United States)

Oka, Mohachiro; Enokizono, Masato; Mori, Yuji; Yamazaki, Kazumasa

2018-04-01

Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

Influence of the Operational Wear of the Stator Parts of Shroud Seals on the Economic Efficiency of the Steam Turbines

Science.gov (United States)

Kostyuk, A. G.; Dmitriev, S. S.; Petrunin, B. N.; Gusev, A. A.

2018-01-01

During the operation of steam turbines under transient conditions, due to different thermal expansion of the stator and rotor parts in the radial and axial directions, the clearances fixed in the course of assembling the seals of the flow path change, which causes rubbing in the seals and the wear of the latter. This inevitably increases the leakages through the seals. A particularly large difference in the relative axial and radial displacements of the rotor and stator parts is observed during the turbine start-ups when the difference in their temperature expansion is maximal. Upon the turbine stops, the turbine shafting runs down freely, as a rule, passing through all critical speeds at which the amplitude of the shafting oscillations reach their peak values, which also leads to seizures in the seals and their wear and tear. The seizures in the seals may also be a consequence of the eccentricity between the rotor and stator caused by the thermal strain of the stator, incorrect choice of the clearances, floating-up of the rotor in the bearing, and many other factors. Recently, standard shroud labyrinth seals are being replaced in the steam turbines by seals with honeycomb stator inserts, the design of which allows the ridges to cut into the honeycomb surface without damaging the former, which allows fixing a radial clearance in the seals of 0.5 mm. On the honeycomb surface where the ridges touch it, grooves are cut through. The wear of the shroud seals reduces the efficiency of the steam turbines during the operation to the greatest degree. However, by the present there have been no exact quantitative data available on the change in the leakage through the worn-out honeycomb seals. The paper presents the results of comparative experimental studies on the flow and power characteristics of seal models with smooth and honeycomb stator parts for various degrees of their wear. The studies showed that the leakages through the worn-out stator parts of the honeycomb seals

Sequential cooling insert for turbine stator vane

Science.gov (United States)

Jones, Russel B

2017-04-04

A sequential flow cooling insert for a turbine stator vane of a small gas turbine engine, where the impingement cooling insert is formed as a single piece from a metal additive manufacturing process such as 3D metal printing, and where the insert includes a plurality of rows of radial extending impingement cooling air holes alternating with rows of radial extending return air holes on a pressure side wall, and where the insert includes a plurality of rows of chordwise extending second impingement cooling air holes on a suction side wall. The insert includes alternating rows of radial extending cooling air supply channels and return air channels that form a series of impingement cooling on the pressure side followed by the suction side of the insert.

Prediction and Optimization of Key Performance Indicators in the Production of Stator Core Using a GA-NN Approach

Science.gov (United States)

Rajora, M.; Zou, P.; Xu, W.; Jin, L.; Chen, W.; Liang, S. Y.

2017-12-01

With the rapidly changing demands of the manufacturing market, intelligent techniques are being used to solve engineering problems due to their ability to handle nonlinear complex problems. For example, in the conventional production of stator cores, it is relied upon experienced engineers to make an initial plan on the number of compensation sheets to be added to achieve uniform pressure distribution throughout the laminations. Additionally, these engineers must use their experience to revise the initial plans based upon the measurements made during the production of stator core. However, this method yields inconsistent results as humans are incapable of storing and analysing large amounts of data. In this article, first, a Neural Network (NN), trained using a hybrid Levenberg-Marquardt (LM) - Genetic Algorithm (GA), is developed to assist the engineers with the decision-making process. Next, the trained NN is used as a fitness function in an optimization algorithm to find the optimal values of the initial compensation sheet plan with the aim of minimizing the required revisions during the production of the stator core.

Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring

Directory of Open Access Journals (Sweden)

João Paulo Bazzo

2016-09-01

Full Text Available This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure.

Experimental verification of the effect of cable length on voltage distribution in stator winding of an induction motor under surge condition

Energy Technology Data Exchange (ETDEWEB)

Oyegoke, B.S. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics

1997-12-31

This paper presents the results of surge distribution tests performed on a stator of a 6 kV induction motor. The primary aim of these tests was to determine the wave propagation properties of the machine winding fed via cables of different lengths. Considering the measured resorts, conclusions are derived regarding the effect of cable length on the surge distribution within the stator winding of an ac motor. (orig.) 15 refs.

Permanent magnet motor drives with switched stator windings

Energy Technology Data Exchange (ETDEWEB)

Nipp, E.

1999-06-01

Permanent magnet (PM) motors are today regarded as an interesting solution for a wide range of inverter-fed variable-speed drives. The generally increased interest in these motors has led to many investigations on their feasibility for vehicle propulsion. Consequently, they are also of interest for traction applications which led to the research project that is presented in this thesis. The most important advantages that are expected in comparison to the state of the art asynchronous motors are lower losses and a higher torque density. Often the field weakening speed range is important, but difficult to obtain with PM machines because the inductance in the direction of the magnetization tends to be low. An alternative can be to switch different coils groups of the stator winding into different configurations. This is the central topic of this thesis. Various aspects of the design of PM motor drives are considered with special attention to the requirements for the application of the switched winding concept. The studies were thereby limited to the inner rotor, radial flux topology. It was found that two winding parts per phase, implying four different winding connections, is the only interesting solution. An advantage of switched windings is that the internal voltage of the machine will never exceed the maximum inverter output, which increases the operation safety. Furthermore the machine design can uncompromisingly be optimized for operation below base speed, which means low inductances implying a large air gap length and thick magnets. A problem with switched windings is that circulating currents can occur. To diminish them, a 2/3 magnet covering of the pole surface must be chosen in combination with a non-salient rotor. Moreover it was found that the eddy current losses in the magnets can reach non-negligible levels and must be considered when designing a drive system. The major drawback of switched stator windings is probably the occurrence of torque

Stator current harmonics evolution by neural network method based on CFE/SS algorithm for ACEC generator of Rey Power Plant

International Nuclear Information System (INIS)

Soleymani, S.; Ranjbar, A.M.; Mirabedini, H.

2001-01-01

One method for on-line fault diagnosis in synchronous generator is stator current harmonics analysis. Then artificial neural network is considered in this paper in order to evaluate stator current harmonics in different loads. Training set of artificial neural network is made ready by generator modeling, finite element method and state space model. Many points from generator capability curve are used in order to complete this set. Artificial neural network which is used in this paper is a percept ron network with a single hidden layer, Eight hidden neurons and back propagation algorithm. Results are indicated that the trained artificial neural network can identify stator current harmonics for arbitrary load from the capability curve. The error is less than 10% in comparison with values obtained directly from the CFE-SS algorithm. The rating parameters of modeled generator are 43950 (kV A), 11(KV), 3000 (rpm), 50 (H Z), (P F=0.8)

Design and Performance Improvement of AC Machines Sharing a Common Stator

Science.gov (United States)

Guo, Lusu

With the increasing demand on electric motors in various industrial applications, especially electric powered vehicles (electric cars, more electric aircrafts and future electric ships and submarines), both synchronous reluctance machines (SynRMs) and interior permanent magnet (IPM) machines are recognized as good candidates for high performance variable speed applications. Developing a single stator design which can be used for both SynRM and IPM motors is a good way to reduce manufacturing and maintenance cost. SynRM can be used as a low cost solution for many electric driving applications and IPM machines can be used in power density crucial circumstances or work as generators to meet the increasing demand for electrical power on board. In this research, SynRM and IPM machines are designed sharing a common stator structure. The prototype motors are designed with the aid of finite element analysis (FEA). Machine performances with different stator slot and rotor pole numbers are compared by FEA. An 18-slot, 4-pole structure is selected based on the comparison for this prototype design. Sometimes, torque pulsation is the major drawback of permanent magnet synchronous machines. There are several sources of torque pulsations, such as back-EMF distortion, inductance variation and cogging torque due to presence of permanent magnets. To reduce torque pulsations in permanent magnet machines, all the efforts can be classified into two categories: one is from the design stage, the structure of permanent magnet machines can be optimized with the aid of finite element analysis. The other category of reducing torque pulsation is after the permanent magnet machine has been manufactured or the machine structure cannot be changed because of other reasons. The currents fed into the permanent magnet machine can be controlled to follow a certain profile which will make the machine generate a smoother torque waveform. Torque pulsation reduction methods in both categories will be

A TURBO-GENERATOR DESIGN SYNTHESIS BASED ON THE NUMERICAL-FIELD CALCULATIONS AT VARYING THE NUMBER OF STATOR SLOTS

Directory of Open Access Journals (Sweden)

V. I. Milykh

2016-12-01

Full Text Available Purpose. The work is dedicated to the presentation of the principle of construction and implementation of an automated synthesis system of the turbo-generator (TG electromagnetic system in the case of its modernization. This is done on the example of changing the number of the stator core slots. Methodology. The basis of the synthesis is a TG basic construction. Its structure includes the mathematical and physical-geometrical models, as well as the calculation model for the FEMM software environment, providing the numerical calculations of the magnetic fields and electromagnetic parameters of TG. The mathematical model links the changing and basic dimensions and parameters of the electromagnetic system, provided that the TG power parameters are ensured. The physical-geometrical model is the geometric mapping of the electromagnetic system with the specified physical properties of its elements. This model converts the TG electromagnetic system in a calculation model for the FEMM program. Results. Testing of the created synthesis system is carried out on the example of the 340 MW TG. The geometric, electromagnetic and power parameters of its basic construction and its new variants at the different numbers of the stator slots are compared. The harmonic analysis of the temporal function of the stator winding EMF is also made for the variants being compared. Originality. The mathematical model, relating the new and base parameters of TG at the changing of the number of the stator slots is created. A Lua script, providing the numerical-field calculations of the TG electromagnetic parameters in the FEMM software environment is worked out. Construction of the constructive and calculation models, the numerical-field calculations and delivery of results are performed by a computer automatically, that ensures high efficiency of the TG design process. Practical value. The considered version of the TG modernization on the example of changing the number of the

Stator Vibration Characteristic Identification of Turbogenerator among Single and Composite Faults Composed of Static Air-Gap Eccentricity and Rotor Interturn Short Circuit

Directory of Open Access Journals (Sweden)

Yu-Ling He

2016-01-01

Full Text Available This paper investigates the radial stator vibration characteristics of turbogenerator under the static air-gap eccentricity (SAGE fault, the rotor interturn short circuit (RISC fault, and the composite faults (CFs composed of SAGE and RISC, respectively. Firstly, the impact of the faulty types on the magnetic flux density (MFD is analyzed, based on which the detailed expressions of the magnetic pull per unit area (MPPUA on the stator under different performing conditions are deduced. Then, numerical FEM simulations based on Ansoft and an experimental study are carried out, taking the SDF-9 type fault simulating generator as the study object. It is shown that SAGE will increase the stator vibration at 2f (f is the electrical frequency which already exists even in normal condition, while RISC and CF will bring in stator vibrations at f, 2f, 3f, and 4f at the same time. The vibration amplitudes under CF are larger than those under RISC. As SAGE increases, the vibration amplitudes of each harmonic component under CF will all be increased, while the development of RISC will decrease the 2nd harmonic vibration but meanwhile increase the 4th harmonic vibration. The achievements of this paper are beneficial for fault identification and condition monitoring of the turbogenerator.

A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

Directory of Open Access Journals (Sweden)

Jing Zhao

2017-07-01

Full Text Available A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSPM motor. The influences of rotor pole number on cogging torque, torque ripple and electromagnetic torque are analyzed and a 12-slot/10-pole MSOR-FSPM motor was chosen for further study. Then, several main parameters of the 12-slot/10-pole MSOR-FSPM motor were optimized to reduce the torque ripple. Finally, the utilization of permanent magnet (PM in the MSOR-FSPM motor and a conventional outer-rotor flux-switching permanent-magnet (COR-FSPM motor are compared and analyzed from the point of view of magnetic flux path, and verified by the finite element method (FEM. The FEM results show that the PM volume of MSOR-FSPM motor is only 54.04% of that in a COR-FSPM motor, but its average electromagnetic torque can reach more than 75% of the torque of COR-FSPM motor.

Frequencies in the Vibration Induced by the Rotor Stator Interaction in a Centrifugal Pump Turbine

DEFF Research Database (Denmark)

Rodriguez, Cristian; Egusquiza, Eduard; Santos, Ilmar

2007-01-01

The highest vibration levels in large pump turbines are, in general, originated in the rotor stator interaction (RSI). This vibration has specific characteristics that can be clearly observed in the frequency domain: harmonics of the moving blade passing frequency and a particular relationship am...

Optimized design of resonant controller for stator current harmonic compensation in DFIG wind turbine systems

DEFF Research Database (Denmark)

Liu, Changjin; Chen, Wenjie; Blaabjerg, Frede

2012-01-01

This paper presents an analytical method to optimize the parameters of resonant controller which is used in a Doubly-Fed Induction Generator (DFIG). In the DFIG control system, the fundamental current loop is controlled by PI-controllers, and the stator harmonic current loop is controlled...

Core losses of a permanent magnet synchronous motor with an amorphous stator core under inverter and sinusoidal excitations

Science.gov (United States)

Yao, Atsushi; Sugimoto, Takaya; Odawara, Shunya; Fujisaki, Keisuke

2018-05-01

We report core loss properties of permanent magnet synchronous motors (PMSM) with amorphous magnetic materials (AMM) core under inverter and sinusoidal excitations. To discuss the core loss properties of AMM core, a comparison with non-oriented (NO) core is also performed. In addition, based on both experiments and numerical simulations, we estimate higher (time and space) harmonic components of the core losses under inverter and sinusoidal excitations. The core losses of PMSM are reduced by about 59% using AMM stator core instead of NO core under sinusoidal excitation. We show that the average decrease obtained by using AMM instead of NO in the stator core is about 94% in time harmonic components.

Core losses of a permanent magnet synchronous motor with an amorphous stator core under inverter and sinusoidal excitations

Directory of Open Access Journals (Sweden)

Atsushi Yao

2018-05-01

Full Text Available We report core loss properties of permanent magnet synchronous motors (PMSM with amorphous magnetic materials (AMM core under inverter and sinusoidal excitations. To discuss the core loss properties of AMM core, a comparison with non-oriented (NO core is also performed. In addition, based on both experiments and numerical simulations, we estimate higher (time and space harmonic components of the core losses under inverter and sinusoidal excitations. The core losses of PMSM are reduced by about 59% using AMM stator core instead of NO core under sinusoidal excitation. We show that the average decrease obtained by using AMM instead of NO in the stator core is about 94% in time harmonic components.

Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

Directory of Open Access Journals (Sweden)

Youssef Agrebi

2007-09-01

Full Text Available In this paper, a conventional indirect stator flux oriented controlled (ISFOC induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed from measured terminal voltages and currents. The IP gains speed controller and PI gains current controller are calculated and tuned at each sampling time according to the new estimated rotor speed. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load; and stability is preserved. Experimental results obtained with a general-purpose 1-kW induction machine are presented showing the effectiveness of the proposed approach in terms of dynamic performance.

Unsteady adjoint for large eddy simulation of a coupled turbine stator-rotor system

Science.gov (United States)

Talnikar, Chaitanya; Wang, Qiqi; Laskowski, Gregory

2016-11-01

Unsteady fluid flow simulations like large eddy simulation are crucial in capturing key physics in turbomachinery applications like separation and wake formation in flow over a turbine vane with a downstream blade. To determine how sensitive the design objectives of the coupled system are to control parameters, an unsteady adjoint is needed. It enables the computation of the gradient of an objective with respect to a large number of inputs in a computationally efficient manner. In this paper we present unsteady adjoint solutions for a coupled turbine stator-rotor system. As the transonic fluid flows over the stator vane, the boundary layer transitions to turbulence. The turbulent wake then impinges on the rotor blades, causing early separation. This coupled system exhibits chaotic dynamics which causes conventional adjoint solutions to diverge exponentially, resulting in the corruption of the sensitivities obtained from the adjoint solutions for long-time simulations. In this presentation, adjoint solutions for aerothermal objectives are obtained through a localized adjoint viscosity injection method which aims to stabilize the adjoint solution and maintain accurate sensitivities. Preliminary results obtained from the supercomputer Mira will be shown in the presentation.

On Line Stator Resistance Tuning of DTC Control CSI Fed IM Drives

OpenAIRE

PANNEER SELVAM

2012-01-01

Current source inverter (CSI) fed drives are employed in high power applications. The conventional CSI drives suffer from drawbacks such as harmonic resonance, unstable operation at low speed ranges, and torque pulsation. CSI fed drives with Direct Torque Control (DTC) has drawn the attention of the motor drives designers because its implementation requires no position sensor. Crucial to the success of this scheme is the estimation of electromagnetic torque and stator flux linkages using the ...

Toward Understanding Tip Leakage Flows in Small Compressor Cores Including Stator Leakage Flow

Science.gov (United States)

Berdanier, Reid A.; Key, Nicole L.

2017-01-01

The focus of this work was to provide additional data to supplement the work reported in NASA/CR-2015-218868 (Berdanier and Key, 2015b). The aim of that project was to characterize the fundamental flow physics and the overall performance effects due to increased rotor tip clearance heights in axial compressors. Data have been collected in the three-stage axial research compressor at Purdue University with a specific focus on analyzing the multistage effects resulting from the tip leakage flow. Three separate rotor tip clearances were studied with nominal tip clearance gaps of 1.5 percent, 3.0 percent, and 4.0 percent based on a constant annulus height. Overall compressor performance was previously investigated at four corrected speedlines (100 percent, 90 percent, 80 percent, and 68 percent) for each of the three tip clearance configurations. This study extends the previously published results to include detailed steady and time-resolved pressure data at two loading conditions, nominal loading (NL) and high loading (HL), on the 100 percent corrected speedline for the intermediate clearance level (3.0 percent). Steady detailed radial traverses of total pressure at the exit of each stator row are supported by flow visualization techniques to identify regions of flow recirculation and separation. Furthermore, detailed radial traverses of time-resolved total pressures at the exit of each rotor row have been measured with a fast-response pressure probe. These data were combined with existing three-component velocity measurements to identify a novel technique for calculating blockage in a multistage compressor. Time-resolved static pressure measurements have been collected over the rotor tips for all rotors with each of the three tip clearance configurations for up to five loading conditions along the 100 percent corrected speedline using fast-response piezoresistive pressure sensors. These time-resolved static pressure measurements reveal new knowledge about the

Heat transfer and flow region characteristics study in a non-annular channel between rotor and stator

Directory of Open Access Journals (Sweden)

Nili-Ahmadabadi M.

2012-01-01

Full Text Available This paper will present the results of the experimental investigation of heat transfer in a non-annular channel between rotor and stator similar to a real generator. Numerous experiments and numerical studies have examined flow and heat transfer characteristics of a fluid in an annulus with a rotating inner cylinder. In the current study, turbulent flow region and heat transfer characteristics have been studied in the air gap between the rotor and stator of a generator. The test rig has been built in a way which shows a very good agreement with the geometry of a real generator. The boundary condition supplies a non-homogenous heat flux through the passing air channel. The experimental devices and data acquisition method are carefully described in the paper. Surface-mounted thermocouples are located on the both stator and rotor surfaces and one slip ring transfers the collected temperature from rotor to the instrument display. The rotational speed of rotor is fixed at three under: 300rpm, 900 rpm and 1500 rpm. Based on these speeds and hydraulic diameter of the air gap, the Reynolds number has been considered in the range: 4000

Feasibility of using PZT actuators to study the dynamic behavior of a rotating disk due to rotor-stator interaction.

Science.gov (United States)

Presas, Alexandre; Egusquiza, Eduard; Valero, Carme; Valentin, David; Seidel, Ulrich

2014-07-07

In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids-air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm) connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction.

Feasibility of Using PZT Actuators to Study the Dynamic Behavior of a Rotating Disk due to Rotor-Stator Interaction

Directory of Open Access Journals (Sweden)

Alexandre Presas

2014-07-01

Full Text Available In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids—air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction.

Punching influence on magnetic properties of the stator teeth of an induction motor

International Nuclear Information System (INIS)

Kedous-Lebouc, A.; Cornut, B.; Perrier, J.C.; Manfe, Ph.; Chevalier, Th.

2003-01-01

In order to study the effects of punching of electrical steel sheets, a suitable geometrical structure able to characterize the stator teeth behavior of an induction motor is proposed and validated. The influence of the punching on a fully processed M330-65A is then characterized. A spectacular degradation of loss and B(H) curves is observed. This leads to a perceptible increase of the no-load machine current

Protection from ground faults in the stator winding of generators at power plants in the Siberian networks

International Nuclear Information System (INIS)

Vainshtein, R. A.; Lapin, V. I.; Naumov, A. M.; Doronin, A. V.; Yudin, S. M.

2010-01-01

The experience of many years of experience in developing and utilization of ground fault protection in the stator winding of generators in the Siberian networks is generalized. The main method of protection is to apply a direct current or an alternating current with a frequency of 25 Hz to the primary circuits of the stator. A direct current is applied to turbo generators operating in a unit with a transformer without a resistive coupling to the external grid or to other generators. Applying a 25 Hz control current is appropriate for power generation systems with compensation of a capacitive short circuit current to ground. This method forms the basis for protection of generators operating on busbars, hydroelectric generators with a neutral grounded through an arc-suppression reactor, including in consolidated units with generators operating in parallel on a single low-voltage transformer winding.

Drive equipment of the TRANSRAPID 06 with an iron bearing synchronous long stator motor

Energy Technology Data Exchange (ETDEWEB)

Parsch, C P; Ciessow, G

1981-01-01

For the testing of an application orientated Maglev the TRANSRAPID test center Emsland is being installed by the joint venture TRANSRAPID. The drive of the vehicle TRANSRAPID 06 is realized by an iron bearing synchronous long stator motor. A description is given of the principle of this drive, the output of traction motor and substation and of the dynamics of vehicle movement's calculations.

Theoretical modelling, analysis and validation of the shaft motion and dynamic forces during rotor–stator contact

DEFF Research Database (Denmark)

Lahriri, Said; Santos, Ilmar

2013-01-01

and stator. Expressions for the restoring magnetic forces are derived using Biot Savart law for uniformed magnetised bar magnets and the contact forces are derived by use of a compliant contact force model. The theoretical mathematical model is verified with experimental results, and shows good agreements...

Incipient Stator Insulation Fault Detection of Permanent Magnet Synchronous Wind Generators Based on Hilbert–Huang Transformation

DEFF Research Database (Denmark)

Wang, Chao; Liu, Xiao; Chen, Zhe

2014-01-01

of insulation degradation of one turn in the winding of a PMSWG. Cosimulation method by combining finite element model and external circuits is used. Hilbert–Huang transformation is applied to detect the very early stage fault in interturn insulation by analyzing the stator current. Detection results show...

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

Science.gov (United States)

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.

Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles

Science.gov (United States)

Beauchamp, E. D.; Hadfield, J. R.; Wuertz, K. L.

1983-01-01

A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.

Torque Characteristic Analysis of a Transverse Flux Motor Using a Combined-Type Stator Core

Directory of Open Access Journals (Sweden)

Xiaobao Yang

2016-11-01

Full Text Available An external rotor transverse flux motor using a combined-type stator core is proposed for a direct drive application in this paper. The stator core is combined by two kinds of components that can both be manufactured conveniently by generic laminated silicon steel used in traditional motors. The motor benefits from the predominance of low manufacturing cost and low iron loss by using a silicon-steel sheet. Firstly, the basic structure and operation principles of the proposed motor are introduced. Secondly, the expressions of the electromagnetic torque and the cogging torque are deduced by theoretical analysis. Thirdly, the basic characteristics such as permanent magnet flux linkage, no-load back electromotive force, cogging torque and electromagnetic torque are analyzed by a three-dimensional finite element method (3D FEM. Then, the influence of structure parameters on the torque density is investigated, which provides a useful foundation for optimum design of the novel motor. Finally, the torque density of the proposed motor is calculated and discussed, and the result shows that the proposed motor in this paper can provide considerable torque density by using few permanent magnets.

Dynamic Model of Contact Interface between Stator and Rotor

Directory of Open Access Journals (Sweden)

ZengHui Zhao

2013-01-01

Full Text Available Based on the equivalent principle, a linear spring contact model was established for the friction layer between stator and rotor. Different contact conditions were described by a distance index δ. Detailed analysis of the nonlinear contact behavior especially the static and dynamic slipping was carried on using a space-time equation. A contact deflection angle was proposed to quantitatively express the influence of friction force on the output performance. A more precision simulation model was established based on the theoretical analysis, and influences of different preload pressures and elastic modulus Em of friction layer on output performance were analyzed. The results showed the simulation results had very good consistency with experimental results, and the model could well reflect the output characteristics of contact interface.

Numerical Investigation of Compressor Non-Synchronous Vibration with Full Annulus Rotor-Stator Interaction

Science.gov (United States)

Espinal, Daniel

The objective of this research is to investigate and confirm the periodicity of the Non-Synchronous Vibration (NSV) mechanism of a GE axial compressor with a full-annulus simulation. A second objective is to develop a high fidelity single-passage tool with time-accurate unsteady capabilities able to capture rotor-stator interactions and NSV excitation response. A high fidelity methodology for axial turbomachinery simulation is developed using the low diffusion shock-capturing Riemann solver with high order schemes, the Spalart-Allmaras turbulence closure model, the fully conservative unsteady sliding BC for rotor-stator interaction with extension to full-annulus and single-passage configurations, and the phase lag boundary conditions applied to rotor-stator interface and circumferential BC. A URANS solver is used and captures the NSV flow excitation frequency of 2439 Hz, which agrees reasonably well with the measured NSV frequency of 2600 Hz from strain gage test data. It is observed that the circumferentially traveling vortex formed in the vicinity of the rotor tip propagates at the speed of a non-engine order frequency and causes the NSV. The vortex travels along the suction surface of the blade and crosses the passage outlet near blade trailing edge. Such a vortex motion trajectory repeats in each blade passage and generates two low pressure regions due to the vortex core positions, one at the leading edge and one at the trailing edge, both are oscillating due to the vortex coming and leaving. These two low pressure regions create a pair of coupling forces that generates a torsion moment causing NSV. The full-annulus simulation shows that the circumferentially traveling vortex has fairly periodical behavior and is a full annulus structure. Also, frequencies below the NSV excitation frequency of 2439 Hz with large amplitudes in response to flow-separation related phenomena are present. This behavior is consistent with experimental measurements. For

Fault Diagnosis System of Induction Motors Based on Neural Network and Genetic Algorithm Using Stator Current Signals

Directory of Open Access Journals (Sweden)

Tian Han

2006-01-01

Full Text Available This paper proposes an online fault diagnosis system for induction motors through the combination of discrete wavelet transform (DWT, feature extraction, genetic algorithm (GA, and neural network (ANN techniques. The wavelet transform improves the signal-to-noise ratio during a preprocessing. Features are extracted from motor stator current, while reducing data transfers and making online application available. GA is used to select the most significant features from the whole feature database and optimize the ANN structure parameter. Optimized ANN is trained and tested by the selected features of the measurement data of stator current. The combination of advanced techniques reduces the learning time and increases the diagnosis accuracy. The efficiency of the proposed system is demonstrated through motor faults of electrical and mechanical origins on the induction motors. The results of the test indicate that the proposed system is promising for the real-time application.

Experimental Characterization and Modeling of Thermal Contact Resistance of Electric Machine Stator-to-Cooling Jacket Interface Under Interference Fit Loading

Energy Technology Data Exchange (ETDEWEB)

Cousineau, Justine E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chieduko, Victor [UQM Technologies, Inc.; Lall, Rajiv [UQM Technologies, Inc.; Gilbert, Alan [UQM Technologies, Inc.

2018-05-08

Cooling of electric machines is a key to increasing power density and improving reliability. This paper focuses on the design of a machine using a cooling jacket wrapped around the stator. The thermal contact resistance (TCR) between the electric machine stator and cooling jacket is a significant factor in overall performance and is not well characterized. This interface is typically an interference fit subject to compressive pressure exceeding 5 MPa. An experimental investigation of this interface was carried out using a thermal transmittance setup using pressures between 5 and 10 MPa. The results were compared to currently available models for contact resistance, and one model was adapted for prediction of TCR in future motor designs.

Turbulence characteristics of the Bödewadt layer in a large enclosed rotor-stator system

Science.gov (United States)

Randriamampianina, Anthony; Poncet, Sébastien

2006-05-01

A three-dimensional (3D) direct numerical simulation is combined with a laboratory study to describe the turbulent flow in an enclosed annular rotor-stator cavity characterized by a large aspect ratio G =(b-a)/h=18.32 and a small radius ratio a /b=0.152, where a and b are the inner and outer radii of the rotating disk and h is the interdisk spacing. The rotation rate Ω under consideration is equivalent to the rotational Reynolds number Re =Ωb2/ν=9.5×104, where ν is the kinematic viscosity of the fluid. This corresponds to a value at which an experiment carried out at the laboratory has shown that the stator boundary layer is turbulent, whereas the rotor boundary layer is still laminar. Comparisons of the 3D computed solution with velocity measurements have given good agreement for the mean and turbulent fields. The results enhance evidence of weak turbulence at this Reynolds number, by comparing the turbulence properties with available data in the literature [M. Lygren and H. I. Andersson, J. Fluid Mech. 426, 297 (2001)]. An approximately self-similar boundary layer behavior is observed along the stator side. The reduction of the structural parameter a1 under the typical value 0.15 and the variation in the wall-normal direction of the different characteristic angles show that this boundary layer is three-dimensional. A quadrant analysis [H. S. Kang, H. Choi, and J. Y. Yoo, Phys. Fluids 10, 2315 (1998)] of conditionally averaged velocities is performed to identify the contributions of different events (ejections and sweeps) on the Reynolds shear stress producing vortical structures. The asymmetries observed in the conditionally averaged quadrant analysis are dominated by Reynolds stress-producing events in this Bödewadt layer. Moreover, case 1 vortices (with a positive wall induced velocity) are found to be the major source of generation of special strong events, in agreement with the conclusions of Lygren and Andersson [J. Fluid Mech. 426, 297 (2001)].

Improving the reliability of stator insulation system in rotating machines

International Nuclear Information System (INIS)

Gupta, G.K.; Sedding, H.G.; Culbert, I.M.

1997-01-01

Reliable performance of rotating machines, especially generators and primary heat transport pump motors, is critical to the efficient operation on nuclear stations. A significant number of premature machine failures have been attributed to the stator insulation problems. Ontario Hydro has attempted to assure the long term reliability of the insulation system in critical rotating machines through proper specifications and quality assurance tests for new machines and periodic on-line and off-line diagnostic tests on machines in service. The experience gained over the last twenty years is presented in this paper. Functional specifications have been developed for the insulation system in critical rotating machines based on engineering considerations and our past experience. These specifications include insulation stress, insulation resistance and polarization index, partial discharge levels, dissipation factor and tip up, AC and DC hipot tests. Voltage endurance tests are specified for groundwall insulation system of full size production coils and bars. For machines with multi-turn coils, turn insulation strength for fast fronted surges in specified and verified through tests on all coils in the factory and on samples of finished coils in the laboratory. Periodic on-line and off-line diagnostic tests were performed to assess the condition of the stator insulation system in machines in service. Partial discharges are measured on-line using several techniques to detect any excessive degradation of the insulation system in critical machines. Novel sensors have been developed and installed in several machines to facilitate measurements of partial discharges on operating machines. Several off-line tests are performed either to confirm the problems indicated by the on-line test or to assess the insulation system in machines which cannot be easily tested on-line. Experience with these tests, including their capabilities and limitations, are presented. (author)

Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine

International Nuclear Information System (INIS)

Nicolet, C; Ruchonnet, N; Alligne, S; Avellan, F; Koutnik, J

2010-01-01

Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

Analysis of Pressure Pulsation Induced by Rotor-Stator Interaction in Nuclear Reactor Coolant Pump

Directory of Open Access Journals (Sweden)

Xu Zhang

2017-01-01

Full Text Available The internal flow of reactor coolant pump (RCP is much more complex than the flow of a general mixed-flow pump due to high temperature, high pressure, and large flow rate. The pressure pulsation that is induced by rotor-stator interaction (RSI has significant effects on the performance of pump; therefore, it is necessary to figure out the distribution and propagation characteristics of pressure pulsation in the pump. The study uses CFD method to calculate the behavior of the flow. Results show that the amplitudes of pressure pulsation get the maximum between the rotor and stator, and the dissipation rate of pressure pulsation in impellers passage is larger than that in guide vanes passage. The behavior is associated with the frequency of pressure wave in different regions. The flow rate distribution is influenced by the operating conditions. The study finds that, at nominal flow, the flow rate distribution in guide vanes is relatively uniform and the pressure pulsation amplitude is the smallest. Besides, the vortex shedding or backflow from the impeller blade exit has the same frequency as pressure pulsation but there are phase differences, and it has been confirmed that the absolute value of phase differences reflects the vorticity intensity.

Microcontroller based Stator Winding Resistance Determination of Induction Motor Drive on Temperature Variations

OpenAIRE

Siraj Ahmed T; Sukhdeo Sao; K.S.R Anjaneyulu

2014-01-01

In this paper an experiment has been conducted to determine the online stator winding resistance of an induction motor, in industries as well as domestic purpose induction motors is largely utilized, as it has both applications of variable and constant torque operation nature. The major requirement of an electric drive system is its independent control of torque and speed; this is achieved in DC motor Drive but has more disadvantages. With the help of fast acting switching devices it is possi...

Compact piezoelectric micromotor with a single bulk lead zirconate titanate stator

Science.gov (United States)

Yan, Liang; Lan, Hua; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

2013-04-01

The advance of micro/nanotechnology promotes the development of micromotors in recent years. In this article, a compact piezoelectric ultrasonic micromotor with a single bulk lead zirconate titanate stator is proposed. A traveling wave is generated by superposition of bending modes with 90° phase difference excited by d15 inverse piezoelectric effects. The operating principle simplifies the system structure significantly, and provides a miniaturization solution. A research prototype with the size of 0.75× 0.75×1.55 mm is developed. It can produce start-up torque of 0.27μNmand maximum speed of 2760 r/min at 14RMS.

An evaluation of alternative stator lamination materials for a high-speed, 1.5 MW, permanent magnet generator

NARCIS (Netherlands)

Paulides, J.J.H.; Jewell, G.W.; Howe, D.

2004-01-01

The influence of the choice of stator lamination material on the iron loss in a high speed, high power permanent magnet generator, which is interfaced to a DC link via a simple bridge rectifier, is investigated. The rating of the generator is representative of machines which would be employed in

An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

Science.gov (United States)

Gayen, P K; Chatterjee, D; Goswami, S K

2016-05-01

In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Novel model of stator design to reduce the mass of superconducting generators

Science.gov (United States)

Kails, Kevin; Li, Quan; Mueller, Markus

2018-05-01

High temperature superconductors (HTS), with much higher current density than conventional copper wires, make it feasible to develop very powerful and compact power generators. Thus, they are considered as one promising solution for large (10 + MW) direct-drive offshore wind turbines due to their low tower head mass. However, most HTS generator designs are based on a radial topology, which requires an excessive amount of HTS material and suffers from cooling and reliability issues. Axial flux machines on the other hand offer higher torque/volume ratios than the radial machines, which makes them an attractive option where space and transportation becomes an issue. However, their disadvantage is heavy structural mass. In this paper a novel stator design is introduced for HTS axial flux machines which enables a reduction in their structural mass. The stator is for the first time designed with a 45° angle that deviates the air gap closing forces into the vertical direction reducing the axial forces. The reduced axial forces improve the structural stability and consequently simplify their structural design. The novel methodology was then validated through an existing design of the HTS axial flux machine achieving a ∼10% mass reduction from 126 tonnes down to 115 tonnes. In addition, the air gap flux density increases due to the new claw pole shapes improving its power density from 53.19 to 61.90 W kg‑1. It is expected that the HTS axial flux machines designed with the new methodology offer a competitive advantage over other proposed superconducting generator designs in terms of cost, reliability and power density.

A fast semi-analytical model for the slotted structure of induction motors with 36/28 stator/rotor slot combination

NARCIS (Netherlands)

Sprangers, R.L.J.; Paulides, J.J.H.; Gysen, B.L.J.; Lomonova, E.A.

2014-01-01

A fast, semi-analyticalmodel for inductionmotors (IMs) with 36/28 stator/rotor slot combination is presented. In comparison to traditional analytical models for IMs, such as lumped parameter, magnetic equivalent circuit and anisotropic layer models, the presented model calculates a continuous

A variable-mode stator consequent pole memory machine

Science.gov (United States)

Yang, Hui; Lyu, Shukang; Lin, Heyun; Zhu, Z. Q.

2018-05-01

In this paper, a variable-mode concept is proposed for the speed range extension of a stator-consequent-pole memory machine (SCPMM). An integrated permanent magnet (PM) and electrically excited control scheme is utilized to simplify the flux-weakening control instead of relatively complicated continuous PM magnetization control. Due to the nature of memory machine, the magnetization state of low coercive force (LCF) magnets can be easily changed by applying either a positive or negative current pulse. Therefore, the number of PM poles may be changed to satisfy the specific performance requirement under different speed ranges, i.e. the machine with all PM poles can offer high torque output while that with half PM poles provides wide constant power range. In addition, the SCPMM with non-magnetized PMs can be considered as a dual-three phase electrically excited reluctance machine, which can be fed by an open-winding based dual inverters that provide direct current (DC) bias excitation to further extend the speed range. The effectiveness of the proposed variable-mode operation for extending its operating region and improving the system reliability is verified by both finite element analysis (FEA) and experiments.

Numerical method for calculation of 3D viscous turbomachine flow taking into account stator/rotor unsteady interaction

Energy Technology Data Exchange (ETDEWEB)

Rusanov, A V; Yershov, S V [Institute of Mechanical Engineering Problems of National Academy of Sciences of Ukraine Kharkov (Ukraine)

1998-12-31

The numerical method is suggested for the calculation of the 3D periodically unsteady viscous cascade flow evoked by the aerodynamics interaction of blade rows. Such flow is described by the thin-layer Reynolds-averaged unsteady Navier-Stokes equations. The turbulent effects are simulated with the modified Baldwin-Lomax turbulence model. The problem statement allows to consider an unsteady flow through either a single turbo-machine stage or a multi stage turbomachine. The sliding mesh techniques and the time-space non-oscillatory square interpolation are used in axial spacings to calculate the flow in a computational domain that contains the reciprocally moving elements. The gasdynamical equations are integrated numerically with the implicit quasi-monotonous Godunov`s type ENO scheme of the second or third order of accuracy. The suggested numerical method is incorporated in the FlowER code developed by authors for calculations of the 3D viscous compressible flows through multi stage turbomachines. The numerical results are presented for unsteady turbine stage throughflows. The method suggested is shown to simulate qualitatively properly the main unsteady cascade effects in particular the periodically blade loadings, the propagation of stator wakes through rotor blade passage and the unsteady temperature flowfields for stages with cooled stator blades. (author) 21 refs.

Numerical method for calculation of 3D viscous turbomachine flow taking into account stator/rotor unsteady interaction

Energy Technology Data Exchange (ETDEWEB)

Rusanov, A.V.; Yershov, S.V. [Institute of Mechanical Engineering Problems of National Academy of Sciences of Ukraine Kharkov (Ukraine)

1997-12-31

The numerical method is suggested for the calculation of the 3D periodically unsteady viscous cascade flow evoked by the aerodynamics interaction of blade rows. Such flow is described by the thin-layer Reynolds-averaged unsteady Navier-Stokes equations. The turbulent effects are simulated with the modified Baldwin-Lomax turbulence model. The problem statement allows to consider an unsteady flow through either a single turbo-machine stage or a multi stage turbomachine. The sliding mesh techniques and the time-space non-oscillatory square interpolation are used in axial spacings to calculate the flow in a computational domain that contains the reciprocally moving elements. The gasdynamical equations are integrated numerically with the implicit quasi-monotonous Godunov`s type ENO scheme of the second or third order of accuracy. The suggested numerical method is incorporated in the FlowER code developed by authors for calculations of the 3D viscous compressible flows through multi stage turbomachines. The numerical results are presented for unsteady turbine stage throughflows. The method suggested is shown to simulate qualitatively properly the main unsteady cascade effects in particular the periodically blade loadings, the propagation of stator wakes through rotor blade passage and the unsteady temperature flowfields for stages with cooled stator blades. (author) 21 refs.

FEM analysis of an single stator dual PM rotors axial synchronous machine

Science.gov (United States)

Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

2017-01-01

The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors. The proposed topologies, the magneto-motive force analysis and quasi 3D-FEM analysis are the core of the paper.

Transportation of a 451 ton generator stator and a 234 ton generator rotor from Hartsville, TN, to Los Alamos, NM

International Nuclear Information System (INIS)

Boenig, H.J.; Rogers, J.D.; McLelland, G.R.; Pelts, C.T.

1989-01-01

A 1430 MVA steam turbine generator was acquired from a cancelled nuclear power plant in Tennessee to be used as the pulsed power and energy storage unit for the Confinement Physics Research Facility being built at Los Alamos, NM. The transportation from Hartsville, near Nashville, TN, to Los Alamos, NM, of the two largest single pieces of the generator, a 451 t stator and a 234 t rotor presented a special challenge. Details of the move, by barge from Hartsville to Catoosa, near Tulsa, OK, by rail from Catoosa to Lamy, near Santa Fe, NM, and by road from Lamy to Los Alamos are described. The greatest difficulty of the successful move was the crossing of the Rio Grande river on an existing reinforced concrete bridge. The two-lane wide road transporters for the stator and rotor were fitted with outriggers to provide a four-lane wide vehicle, thus spreading the load over the entire bridge width and meeting acceptable load distribution and bridge safety factors. 2 refs., 6 figs

Observer-based estimation of stator-winding faults in delta-connected induction motors

DEFF Research Database (Denmark)

Skovemose Kallesøe, Carsten; Izadi-Zamanabadi, Roozbeh; Vadstrup, Pierre

2007-01-01

This paper addresses the subject of interturn short circuit estimation in the stator of a delta-connected induction motor. In this paper, an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved...... in the short circuit, and an expression of the current in the short circuit. Moreover, the currents are made available even though a fault has occurred in the motor. To be able to develop this observer, a model that is particularly suitable for the chosen observer design, is also derived. The effeciency...... of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate interturn short-circuit faults....

Design of the robust synchronous generator stator voltage regulator based on the interval plant model

Directory of Open Access Journals (Sweden)

Stojić Đorđe

2013-01-01

Full Text Available In this paper a novel method for the stator voltage regulator of a synchronous generator based on the interval plant mode, is presented. Namely, it is shown in the literature that, in order to design a controller for the first-order compensator, the limited number of interval plants needs to be examined. Consequently, the intervals of the plant model parameter variations used to calculate the four extreme interval plants required for the sequential PI controller design are determined. The controller is designed using frequency-domain-based techniques, while its robust performance is examined using simulation tests.

Field-oriented control of five-phase induction motor with open-end stator winding

Directory of Open Access Journals (Sweden)

Listwan Jacek

2016-09-01

Full Text Available The mathematical model of the five-phase squirrel-cage induction motor and the system of the dual five-phase voltage source inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase induction motor with an open-end stator winding are described. The structures of the direct fieldoriented control system (DFOC and the Indirect Field-oriented control system (IFOC with PI controllers in outer and inner control loops are analyzed. A method of space vector modulation used to control the system of the dual five-phase voltage source inverter has been discussed. The results of simulation studies of the field-oriented control methods are presented. Comparative analysis of the simulation results was carried out.

Effects of slotting and unipolar flux on magnetic pull in a two-pole induction motor with an extra four-pole stator winding

Energy Technology Data Exchange (ETDEWEB)

Sinervo, A.

2013-06-01

This thesis is about the radial magnetic forces between the rotor and stator in twopole induction machines. The magnetic forces arise from rotor eccentricity. The asymmetric air-gap makes the flux density on one side of the rotor stronger than on the opposite side. This produces magnetic pull. The magnetic flux density distribution in the air-gap can be expressed with spatial harmonics, i.e. flux densities with different pole-pair numbers. In two-pole machines, the main part of the magnetic force is produced by the interaction of two- and fourpole flux unless the four-pole flux is damped by parallel paths in the stator winding or an extra four-pole stator winding. The rest of the force comes from the interaction of two-pole and unipolar flux and from the higher harmonics of the air-gap flux of which the slot harmonics are a major part. The force caused by the higher harmonics and the unipolar flux is studied in the case where a four-pole stator winding is used to reduce the four-pole flux. The higher harmonics are found to produce, in addition to the traditional unbalanced magnetic pull, a force similar to the effect of the unipolar flux and the two can be distinguished only by measuring the unipolar flux. In measurements at various operation points, the higher harmonics are found to produce much more force than the unipolar flux and two-pole flux but the unipolar flux is still significant. The four-pole winding also is used to actively control the four-pole flux and the magnetic forces. Designing the controller requires a low order model of the system. Such a model is derived and the effect of the slot harmonics and the unipolar flux are included in the model. Different measurements techniques and methods are presented to identify and validate the control model. The operation point dependence of the system dynamics is studied via measurements. All results are obtained from a 30 kW test motor. The rotor of the test machine has a long flexible shaft on external

Numerical analysis of hydrodynamics in a rotor-stator reactor for biodiesel synthesis

Energy Technology Data Exchange (ETDEWEB)

Wen, Zhuqing; Petera, Jerzy [Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz (Poland)

2016-06-08

A rotor-stator spinning disk reactor for intensified biodiesel synthesis is described and numerically simulated. The reactor consists of two flat disks, located coaxially and parallel to each other with a gap ranging from 0.1 mm to 0.2 mm between the disks. The upper disk is located on a rotating shaft while the lower disk is stationary. The feed liquids, triglycerides (TG) and methanol are introduced coaxially along the center line of rotating disk and stationary disk, respectively. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction species transport model by the CFD software ANSYS©Fluent v. 13.0. The effects of upper disk’s spinning speed, gap size and flow rates at inlets are evaluated.

Sensorless speed detection of squirrel-cage induction machines using stator neutral point voltage harmonics

Science.gov (United States)

Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo

2009-04-01

In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.

A novel piezoelectric actuator with a screw-coupled stator and rotor for driving an aperture

International Nuclear Information System (INIS)

Li, Xiaoniu; Zhou, Shengqiang

2016-01-01

Variable apertures have become very important in optical applications. This paper presents a new type of piezoelectric actuator with a screw-coupled stator and rotor that is developed to operate an aperture. The actuator and the aperture are integrated to control the luminous flux. To open or close, the aperture only needs to rotate through a limited angle. Therefore, the actuator is designed so that the rotor and the stator are simply connected by a screw to couple the axial preload and the circumferential movement. The torque and velocity of the actuator are produced by its circumferential motion. The preload of the actuator is applied by deforming the rotor along the axial direction. This method of preloading makes it difficult to keep the preload constant during the actuator’s work. To overcome this problem, a novel flexible rotor with a low stiffness is designed. An equivalent stiffness model of the rotor is presented for the design of a flexible rotor. Its design parameters are determined by a numerical model and confirmed using the finite element method. A prototype is fabricated to drive the aperture. The experimental results demonstrate a resolution of 20 μrad and a rotational range of 300°. The opening and closing durations of the aperture are 96 ms and 97.2 ms, respectively, for a rotation range of 90°. The rotation angle of the actuator is linearly related to time, which shows that its performance is controlled well. The novel screw-coupled piezoelectric actuator for driving an aperture features high resolution, high speed, simple structure and compact size. (paper)

Modelling of the travelling wave piezoelectric motor stator: an integrated review and new perspective

Directory of Open Access Journals (Sweden)

Rodríguez, H.

2004-06-01

Full Text Available Articles from different areas which are closely related to the modelling of the stator of travelling wave ultrasonic motors (TWUMs are reviewed in this work. Thus, important issues relevant to this problem are identified from the areas of vibration of annular plates, laminated plate theories, and modelling of piezoelectric transducers. From this integrated point of view, it becomes clear that there are some very important issues yet to be addressed in the modelling of TWUMs. Firstly, the influence of material properties and stator dimensions on output efficiency, electromechanical coupling coefficients (EMCC and maximum output energy is to be investigated in more detail. Secondly, the modelling of the electric potential field (by explicitly including the charge equation for TWUMs seems to be a must for better prediction of displacements and electric fields close to the resonance, as suggested by some recent works [1]. Moreover, the improvement of current models by using shear deformation (or higher order laminated plate theories (LPTs in conjunction with approximated methods of solution are discussed. In addition to analytical models, those works using Finite Element and Finite difference Methods (FEM and FDM for the modelling and simulation of the TWUM stator dynamics are reviewed.

En este trabajo se realiza una revisión de los trabajos de investigación realizados en diversas áreas sobre el modelado del estátor de los motores ultrasónicos de onda viajera (TWUMs. Entre los problemas relevantes que se han estudiado podemos citar la vibración de placas anulares, las teorías de placas laminadas y el modelado de transductores piezoeléctricos. A raíz de este punto de vista integral se hace manifiesto que todavía quedan asuntos importantes que estudiar en el modelado de los TWUMs. En primer lugar, la influencia de las propiedades del material y las dimensiones del estátor en la eficiencia del motor, los coeficientes de acoplamiento

Compressible simulation of rotor-stator interaction in pump-turbines

International Nuclear Information System (INIS)

Yan, J; Koutnik, J; Seidel, U; Huebner, B

2010-01-01

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. Finally, the procedure is applied to a 3-dimensional pump configuration in model scale. Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics.

Numerical Analysis of The Effect of Hydrodynamics and Operating Conditions on Biodiesel Synthesis in a Rotor-Stator Spinning Disk Reactor

Directory of Open Access Journals (Sweden)

Wen Zhuqing

2017-06-01

Full Text Available A rotor-stator spinning disk reactor for intensified biodiesel synthesis is described and numerically simulated in the present research. The reactor consists of two flat disks, located coaxially and parallel to each other with a gap ranging from 0.1 mm to 0.2 mm between the disks. The upper disk is located on a rotating shaft while the lower disk is stationary. The feed liquids, triglycerides (TG and methanol are injected into the reactor from centres of rotating disk and stationary disk, respectively. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction multicomponent transport model with the CFD software ANSYS©Fluent v. 13.0. Effect of operating conditions on TG conversion is particularly investigated. Simulation results indicate that there is occurrence of back flow close to the stator at the outlet zone. Small gap size and fast rotational speed generally help to intensify mixing among reagents, and consequently enhance TG conversion. However, increasing rotational speed of spinning disk leads to more backflow, which decreases TG conversion. Large flow rate of TG at inlet is not recommended as well because of the short mean residence time of reactants inside the reactor.

Estimation of Stator winding faults in induction motors using an adaptive observer scheme

DEFF Research Database (Denmark)

Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

2004-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

Estimation of Stator Winding Faults in Induction Motors using an Adaptive Observer Scheme

DEFF Research Database (Denmark)

Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

2004-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

The synchronous long-stator propulsion system for TRANSRAPID; Langstator-Synchronmotorantrieb des TRANSRAPID

Energy Technology Data Exchange (ETDEWEB)

Henning, U [Siemens AG Verkehrstechnik, Erlangen (Germany). Geschaeftsgebiet Fahrzeuge Fernverkehr; Kamp, P G [Siemens AG, Erlangen (Germany). Projektierung und Entwicklung von Stromrichtergeraeten fuer die Bahnstromversorgung; Hochleitner, J [Siemens AG, Erlangen (Germany). Abt. Kombinationstechnik

1996-12-31

The synchronous long-stator motor for the maglev vehicle TRANSRAPID is a propulsion system with proven service maturity. The following paper describes the structure of the propulsion system proposed for maglev revenue service lines and how it meets the requirements for modular design, operation of several vehicles on one line, double-end feeding of power from adjacent substations, as well as for optimum maglev operation with minimum fault susceptibility. The overall concept is described and prototypes incorporating new technologies are presented for the various subsystems and components. The main focus is on the converter and control systems. (orig.) [Deutsch] Der Langstator-Synchronmotorantrieb des TRANSRAPID stellt ein einsatzreifes System dar. Die fuer Anwendungsstrecken entwickelte Struktur des Antriebssystems wird beschrieben. Mit ihr werden die Einsatzanforderungen wie modulare Gestaltung, Betrieb mehrerer Fahrzeuge auf eine Strecke, Doppelspeisung aus benachbarten Unterwerken sowie optimaler und stoerungsarmer Betrieb erfuellt. Neben der Beschreibung des Gesamtkonzeptes werden auch Prototypen fuer Teilsysteme und Komponenten auf der Basis fortschrittlicher Technologien vorgestellt. Schwerpunkte sind dabei Umrichter- und Regelungstechnik. (orig.)

A Method to Transit the Rotor-to-Stator Rubbing to Normal Motion Using the Phase Characteristic

Directory of Open Access Journals (Sweden)

Jieqiong Xu

2014-01-01

Full Text Available A method is proposed to transit the rotor-to-stator rubbing to no-rub motion through active auxiliary bearing. The key point of this technique is to express the attractive domain of no-rub motion based on the phase characteristic and to represent the desired status. The feedback actuation is applied by an active auxiliary bearing to drive the rotor approaching the desired status. After that, the control actuation is turned off. Although the desired status is still in rubbing, it is in the attractive domain of no-rub motion, and the response of the rotor is automatically attracted to no-rub motion.

A Novel Rotor and Stator Magnetic Fields Direct-Orthogonalized Vector Control Scheme for the PMSM Servo System

Directory of Open Access Journals (Sweden)

Shi-Xiong Zhang

2014-02-01

Full Text Available Permanent Magnet Synchronous motor (PMSM has received widespread acceptance in recent years. In this paper, a new rotor and stator Magnetic Fields Direct-Orthogonalized Vector Control (MFDOVC scheme is proposed for PMSM servo system. This method simplified the complex calculation of traditional vector control, a part of the system resource is economized. At the same time, through the simulation illustration validation, the performance of PMSM servo system with the proposed MFDOVC scheme can achieve the same with the complex traditional vector control method, but much simpler calculation is implemented using the proposed method.

Modelling of BLDCM with a double 3-phase stator winding and back EMF harmonics

Directory of Open Access Journals (Sweden)

Drozdowski Piotr

2015-03-01

Full Text Available In this paper the mathematical model of the brushless DC motor (BLDCM with a double 3-phase stator winding is analysed. Both the 3-phase windings are mutually displaced by 30 electrical degree. Special care has been sacrificed to influence of higher harmonics of induced electromotive forces (EMF on electromagnetic torque and zero sequence voltages that may be used for sensorless control. The mathematical model has been presented in natural variables and, after transformation to symmetrical components, in a vector form. This allows, from one side, for formulating the equivalent circuit suitable for circuit oriented simulators (e.g.: Spice, SimPowerSystems of Simulink and, from the other point of view, for analysis of higher harmonics influence on control possibilities. These considerations have been illustrated with some results of four quadrant operation obtainded due to simulation at automatic control.

Experimental Evaluation of Cermet Turbine Stator Blades for Use at Elevated Gas Temperatures

Science.gov (United States)

Chiarito, Patrick T.; Johnston, James R.

1959-01-01

The suitability of cermets for turbine stator blades of a modified turbojet engine was determined at an average turbine-inlet-gas temperature of 2000 F. Such an increase in temperature would yield a premium in thrust from a service engine. Because the cermet blades require no cooling, all the available compressor bleed air could be used to cool a turbine made from conventional ductile alloys. Cermet blades were first run in 100-hour endurance tests at normal gas temperatures in order to evaluate two methods for mounting them. The elevated gas-temperature test was then run using the method of support considered best for high-temperature operation. After 52 hours at 2000 F, one of the group of four cermet blades fractured probably because of end loads resulting from thermal distortion of the spacer band of the nozzle diaphragm. Improved design of a service engine would preclude this cause of premature failure.

Single Stator Dual PM Rotor Synchronous Machine with two-frequency single-inverter control, for the propulsion of hybrid electric vehicles

Directory of Open Access Journals (Sweden)

Topor Marcel

2017-01-01

Full Text Available This paper introduces a novel brushless, single winding and single stator, dual PM rotor axial-air-gap machine capable to deliver independently torque at the two rotors by adequate dual vector control. The proposed topologies, the circuit model, controlled dynamics simulation and preliminary 3D FEM torque production on a case study constitute the core of the paper. The proposed dual mechanical port system should be instrumental in parallel (with planetary gears or series hybrid electric vehicles (HEV aiming at a more compact and efficient electric propulsion system solution.

A geometric approach for fault detection and isolation of stator short circuit failure in a single asynchronous machine

KAUST Repository

Khelouat, Samir

2012-06-01

This paper deals with the problem of detection and isolation of stator short-circuit failure in a single asynchronous machine using a geometric approach. After recalling the basis of the geometric approach for fault detection and isolation in nonlinear systems, we will study some structural properties which are fault detectability and isolation fault filter existence. We will then design filters for residual generation. We will consider two approaches: a two-filters structure and a single filter structure, both aiming at generating residuals which are sensitive to one fault and insensitive to the other faults. Some numerical tests will be presented to illustrate the efficiency of the method.

Observer Based Estimation of Stator Winding Faults in Delta-connected Induction Motors, a LMI Approach

DEFF Research Database (Denmark)

Kallesøe, Carsten; Vadstrup, Pierre; Rasmussen, Henrik

2006-01-01

This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

Tunneling of electrons via rotor–stator molecular interfaces: Combined ab initio and model study

Energy Technology Data Exchange (ETDEWEB)

Petreska, Irina, E-mail: irina.petreska@pmf.ukim.mk [Institute of Physics, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, PO Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Ohanesjan, Vladimir [Institute of Physics, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, PO Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Pejov, Ljupčo [Institute of Chemistry, Department of Physical Chemistry, Ss. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Kocarev, Ljupčo [Macedonian Academy of Sciences and Arts, Krste Misirkov 2, PO Box 428, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Faculty of Computer Science and Engineering, Ss. Cyril and Methodius University, Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of)

2016-07-01

Tunneling of electrons through rotor–stator anthracene aldehyde molecular interfaces is studied with a combined ab initio and model approach. Molecular electronic structure calculated from first principles is utilized to model different shapes of tunneling barriers. Together with a rectangular barrier, we also consider a sinusoidal shape that captures the effects of the molecular internal structure more realistically. Quasiclassical approach with the Simmons’ formula for current density is implemented. Special attention is paid on conformational dependence of the tunneling current. Our results confirm that the presence of the side aldehyde group enhances the interesting electronic properties of the pure anthracene molecule, making it a bistable system with geometry dependent transport properties. We also investigate the transition voltage and we show that conformation-dependent field emission could be observed in these molecular interfaces at realistically low voltages. The present study accompanies our previous work where we investigated the coherent transport via strongly coupled delocalized orbital by application of Non-equilibrium Green’s Function Formalism.

Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications

Science.gov (United States)

Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

2014-03-01

The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications

International Nuclear Information System (INIS)

University of Timisoara, Electrical Engineering Department, Vasile Parvan str., no. 1-2, 300223 Timisoara (Romania))" data-affiliation=" (Politehnica University of Timisoara, Electrical Engineering Department, Vasile Parvan str., no. 1-2, 300223 Timisoara (Romania))" >Tutelea, L N; University of Timisoara, Electrical Engineering Department, Vasile Parvan str., no. 1-2, 300223 Timisoara (Romania))" data-affiliation=" (Politehnica University of Timisoara, Electrical Engineering Department, Vasile Parvan str., no. 1-2, 300223 Timisoara (Romania))" >Boldea, I; University of Timisoara, Department of Electrotechnical Engineering and Industrial Informatics, 5 Revolution Street, Hunedoara, 331128 (Romania))" data-affiliation=" (Politehnica University of Timisoara, Department of Electrotechnical Engineering and Industrial Informatics, 5 Revolution Street, Hunedoara, 331128 (Romania))" >Deaconu, S I; University of Timisoara, Department of Electrotechnical Engineering and Industrial Informatics, 5 Revolution Street, Hunedoara, 331128 (Romania))" data-affiliation=" (Politehnica University of Timisoara, Department of Electrotechnical Engineering and Industrial Informatics, 5 Revolution Street, Hunedoara, 331128 (Romania))" >Popa, G N

2014-01-01

The actual e – continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper

Gas turbine with heating during the expansion in the stator blades

International Nuclear Information System (INIS)

Abd El-Maksoud, Rafea Mohamed

2014-01-01

Highlights: • A new cycle is herein introduced with a concept of heating during the expansion. • Turbine overheating is avoided by reducing significantly the cycle temperature. • Comparison is done with a reheat cycle having a higher maximum cycle temperature. • The cycle performance is higher than the reheat cycle. • Regeneration is used to boost the present cycle efficiency. - Abstract: Reheat is used in the gas turbine to achieve higher power output. However, the reheat process is constrained by the heat quantity given to it and the choice of reheat point. Consequently, this paper introduces a new gas turbine cycle to overcome the reheat drawbacks and having superior features. In this cycle, the reheat process is replaced by processes of heating the expanded gases while passing through different turbine stator blades. Small amount of combusted gases is utilized to flow inside such blades for heating and mixing with the expanded gases. Nevertheless, this is performed with precautions of turbine overheating by reducing significantly the maximum temperature of the present cycle. The simulated results demonstrate that the cycle performance is increased by raising the quantity of heating during the expansion. Additionally, this cycle achieves greater efficient output than the traditional reheat Brayton cycle operating with higher maximum cycle temperature. To boost the present cycle efficiency, regeneration is used making the possibility of such cycle to be competitive to the combined cycle

Windage Power Loss in Gas Foil Bearings and the Rotor-Stator Clearance of High Speed Generators Operating in High Pressure Environments

Science.gov (United States)

Bruckner, Robert J.

2009-01-01

Closed Brayton Cycle (CBC) and Closed Supercritical Cycle (CSC) engines are prime candidates to convert heat from a reactor into electric power for robotic space exploration and habitation. These engine concepts incorporate a permanent magnet starter/generator mounted on the engine shaft along with the requisite turbomachinery. Successful completion of the long-duration missions currently anticipated for these engines will require designs that adequately address all losses within the machine. The preliminary thermal management concept for these engine types is to use the cycle working fluid to provide the required cooling. In addition to providing cooling, the working fluid will also serve as the bearing lubricant. Additional requirements, due to the unique application of these microturbines, are zero contamination of the working fluid and entirely maintenance-free operation for many years. Losses in the gas foil bearings and within the rotor-stator gap of the generator become increasingly important as both rotational speed and mean operating pressure are increased. This paper presents the results of an experimental study, which obtained direct torque measurements on gas foil bearings and generator rotor-stator gaps. Test conditions for these measurements included rotational speeds up to 42,000 revolutions per minute, pressures up to 45 atmospheres, and test gases of nitrogen, helium, and carbon dioxide. These conditions provided a maximum test Taylor number of nearly one million. The results show an exponential rise in power loss as mean operating density is increased for both the gas foil bearing and generator windage. These typical "secondary" losses can become larger than the total system output power if conventional design paradigms are followed. A nondimensional analysis is presented to extend the experimental results into the CSC range for the generator windage.

Design, construction and testing of replacement nuclear coolant pump stators to meet today's equipment reliability expectations

International Nuclear Information System (INIS)

Fostier, L.; Howell, D.

2005-01-01

The reliability expectations of equipment and components in today's nuclear power plant are much greater than three or more decades ago when nuclear plants were first constructed due to economic impact of a failure. Very few components in a pressurized water reactor plant can have as much impact of the plants capacity factor as a catastrophic failure of a reactor coolant pump winding. This paper describes the maintenance approach taken by one North American utility in attempt to preclude such failures. The paper will discuss the challenges of the reactor coolant pump application and the enhancements made in the winding design and construction by the supplier to address failure mechanisms so as to better meet present reliability expectations in accordance with dedicated specifications. The paper will also present the in-process and final testing requirements and limits imposed in an attempt to ensure quality of the machine windings, along with selected test results from the stators that have been designed and constructed to these specifications to date. (author)

Investigation on the Flow in a Rotor-Stator Cavity with Centripetal Through-Flow

Directory of Open Access Journals (Sweden)

Bo Hu

2017-10-01

Full Text Available Daily and Nece distinguished four flow regimes in an enclosed rotor-stator cavity, which are dependent on the circumferential Reynolds number and dimensionless axial gap width. A diagram of the different flow regimes including the respective mean profiles for both tangential and radial velocity was developed. The coefficients for the different flow regimes have also been correlated. In centrifugal pumps and turbines, the centripetal through-flow is quite common from the outer radius of the impeller to the impeller eye, which has a strong influence on the radial pressure distribution, axial thrust and frictional torque. The influence of the centripetal through-flow on the cavity flow with different circumferential Reynolds numbers and dimensionless axial gap width is not sufficiently investigated. It is also quite important to convert the 2D Daily and Nece diagram into 3D by introducing the through-flow coefficient. In order to investigate the impact of the centripetal through-flow, a test rig is designed and built up at the University of Duisburg-Essen. The design of the test rig is described. The impact of the above mentioned parameters on the velocity profile, pressure distribution, axial thrust and frictional torque are presented and analyzed in this paper. The 3D Daily and Nece diagram introducing the through-flow coefficient is also organized in this paper.

Application of Boost Converter to Increase the Speed Range of Dual-stator Winding Induction Generator in Wind Power Systems

DEFF Research Database (Denmark)

Kavousi, Ayoub; Fathi, S. Hamid; Milimonfared, Jafar

2018-01-01

In this paper, a topology using a Dual-stator Winding Induction Generator (DWIG) and a boost converter is proposed for the variable speed wind power application. At low rotor speeds, the generator saturation limits the voltage of the DWIG. Using a boost converter, higher DC voltage can be produced...... while the DWIG operates at Maximum Power Point Tracking (MPPT) even at low speed and low voltage conditions. Semiconductor Excitation Controller (SEC) of the DWIG utilizes Control-Winding Voltage Oriented Control (CWVOC) method to adjust the voltage, considering V/f characteristics. For the proposed...... topology, the SEC capacity and the excitation capacitor is optimized by analyzing the SEC reactive current considering wind turbine power-speed curve, V/f strategy, and the generator parameters. The method shows that the per-unit capacity of the SEC can be limited to the inverse of DWIG magnetizing...

The Design of a Permanent Magnet In-Wheel Motor with Dual-Stator and Dual-Field-Excitation Used in Electric Vehicles

Directory of Open Access Journals (Sweden)

Peng Gao

2018-02-01

Full Text Available The in-wheel motor has received more attention owing to its simple structure, high transmission efficiency, flexible control, and easy integration design. It is difficult to achieve high performance with conventional motors due to their dimensions and structure. This paper presents a new dual-stator and dual-field-excitation permanent-magnet in-wheel motor (DDPMIM that is based on the structure of the conventional in-wheel motor and the structure of both the radial and axial magnetic field motor. The finite element analysis (FEA model of the DDPMIM is established and compared with that of the conventional in-wheel motor. The results show that the DDPMIM achieves a higher output torque at low speeds and that the flux-weakening control strategy is not needed in the full speed range.

Biodiesel production process intensification using a rotor-stator type generator of hydrodynamic cavitation.

Science.gov (United States)

Crudo, Daniele; Bosco, Valentina; Cavaglià, Giuliano; Grillo, Giorgio; Mantegna, Stefano; Cravotto, Giancarlo

2016-11-01

Triglyceride transesterification for biodiesel production is a model reaction which is used to compare the conversion efficiency, yield, reaction time, energy consumption, scalability and cost estimation of different reactor technology and energy source. This work describes an efficient, fast and cost-effective procedure for biodiesel preparation using a rotating generator of hydrodynamic cavitation (HC). The base-catalyzed transesterification (methanol/sodium hydroxide) has been carried out using refined and bleached palm oil and waste vegetable cooking oil. The novel HC unit is a continuous rotor-stator type reactor in which reagents are directly fed into the controlled cavitation chamber. The high-speed rotation of the reactor creates micron-sized droplets of the immiscible reacting mixture leading to outstanding mass and heat transfer and enhancing the kinetics of the transesterification reaction which completes much more quickly than traditional methods. All the biodiesel samples obtained respect the ASTM standard and present fatty acid methyl ester contents of >99% m/m in both feedstocks. The electrical energy consumption of the HC reactor is 0.030kWh per L of produced crude biodiesel, making this innovative technology really quite competitive. The reactor can be easily scaled-up, from producing a few hundred to thousands of liters of biodiesel per hour while avoiding the risk of orifices clogging with oil impurities, which may occur in conventional HC reactors. Furthermore it requires minimal installation space due to its compact design, which enhances overall security. Copyright © 2016 Elsevier B.V. All rights reserved.

Loss measurement and analysis for the prototype generator with HTS stator and permanent magnet rotor

Energy Technology Data Exchange (ETDEWEB)

Song, Peng, E-mail: songp10@mails.tsinghua.edu.cn [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Qu, Timing, E-mail: tmqu@mail.tsinghua.edu.cn [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Yu, Xiaoyu [Department of Mechanical Engineering, Tsinghua University, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Li, Longnian; Gu, Chen [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Li, Xiaohang [Innova Superconductor Technology Co., Ltd., Beijing 100084 (China); Wang, Dewen; Hu, Boping [Beijing Zhong Ke San Huan Hi-Tech Co., Ltd., Beijing 100084 (China); Chen, Duxing [Department Fis, University Autonoma Barcelona, Barcelona 08193 (Spain); Han, Zhenghe [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China)

2013-11-15

Highlights: •A novel prototype HTS generator with HTS armature windings was developed. •No-load loss and the iron loss at low temperature were measured. •The total loss at low temperature is much larger than the room temperature case. •The reason for no-load loss increment at low temperature is discussed. -- Abstract: A prototype HTS synchronous generator with a permanent magnet rotor and HTS armature windings was developed. The rated armature frequency is 10 Hz. The cryogenic Dewar is tightly surrounded outside the iron core. Both HTS coils and the iron core were cooled by using conduction cooling method. During the process of no-load running, the no-load loss power data were obtained through the torque measurement. The temperature evolution characteristics of the stator was measured by PT-100 temperature sensors. These results show that the no-load loss power at around 77 K are much larger than that at room temperature. The possible reason for the no-load loss increment is discussed. The ac loss power of one individual HTS coil used in this generator was also tested. Compared with the iron loss power, the ac loss power is rather small and could be neglected.

Active Control of Low-Speed Fan Tonal Noise Using Actuators Mounted in Stator Vanes: Part III Results

Science.gov (United States)

Sutliff, Daniel L.; Remington, Paul J.; Walker, Bruce E.

2003-01-01

A test program to demonstrate simplification of Active Noise Control (ANC) systems relative to standard techniques was performed on the NASA Glenn Active Noise Control Fan from May through September 2001. The target mode was the m = 2 circumferential mode generated by the rotor-stator interaction at 2BPF. Seven radials (combined inlet and exhaust) were present at this condition. Several different error-sensing strategies were implemented. Integration of the error-sensors with passive treatment was investigated. These were: (i) an in-duct linear axial array, (ii) an induct steering array, (iii) a pylon-mounted array, and (iv) a near-field boom array. The effect of incorporating passive treatment was investigated as well as reducing the actuator count. These simplified systems were compared to a fully ANC specified system. Modal data acquired using the Rotating Rake are presented for a range of corrected fan rpm. Simplified control has been demonstrated to be possible but requires a well-known and dominant mode signature. The documented results here in are part III of a three-part series of reports with the same base title. Part I and II document the control system and error-sensing design and implementation.

Experimental investigation of the microscale rotor-stator cavity flow with rotating superhydrophobic surface

Science.gov (United States)

Wang, Chunze; Tang, Fei; Li, Qi; Wang, Xiaohao

2018-03-01

The flow characteristics of microscale rotor-stator cavity flow and the drag reduction mechanism of the superhydrophobic surface with high shearing stress were investigated. A microscale rotating flow testing system was established based on micro particle image velocimetry (micro-PIV), and the flow distribution under different Reynolds numbers (7.02 × 103 ≤ Re ≤ 3.51 × 104) and cavity aspect ratios (0.013 ≤ G ≤ 0.04) was measured. Experiments show that, for circumferential velocity, the flow field distributes linearly in rotating Couette flow in the case of low Reynolds number along the z-axis, while the boundary layer separates and forms Batchelor flow as the Reynolds number increases. The separation of the boundary layer is accelerated with the increase of cavity aspect ratio. The radial velocities distribute in an S-shape along the z-axis. As the Reynolds number and cavity aspect ratio increase, the maximum value of radial velocity increases, but the extremum position at rotating boundary remains at Z* = 0.85 with no obvious change, while the extremum position at the stationary boundary changes along the z-axis. The model for the generation of flow disturbance and the transmission process from the stationary to the rotating boundary was given by perturbation analysis. Under the action of superhydrophobic surface, velocity slip occurs near the rotating boundary and the shearing stress reduces, which leads to a maximum drag reduction over 51.4%. The contours of vortex swirling strength suggest that the superhydrophobic surface can suppress the vortex swirling strength and repel the vortex structures, resulting in the decrease of shearing Reynolds stress and then drag reduction.

Development of the pump protection system against cavitation on the basis of the stator current signature analysis of drive electric motor

Science.gov (United States)

Kipervasser, M. V.; Gerasimuk, A. V.; Simakov, V. P.

2018-05-01

In the present paper a new registration method of such inadmissible phenomenon as cavitation in the operating mode of centrifugal pump is offered. Influence of cavitation and extent of its development on the value of mechanical power consumed by the pump from the electric motor is studied. On the basis of design formulas the joint mathematical model of centrifugal pumping unit with the synchronous motor is created. In the model the phenomena accompanying the work of a pumping installation in the cavitation mode are considered. Mathematical modeling of the pump operation in the considered emergency operation is carried out. The chart of stator current of the electric motor, depending on the degree of cavitation development of is received. On the basis of the analysis of the obtained data the conclusion on the possibility of registration of cavitation by the current of drive electric motor is made and the functional diagram of the developed protection system is offered, its operation principle is described.

Blade row dynamic digital compression program. Volume 2: J85 circumferential distortion redistribution model, effect of Stator characteristics, and stage characteristics sensitivity study

Science.gov (United States)

Tesch, W. A.; Steenken, W. G.

1978-01-01

The results of dynamic digital blade row compressor model studies of a J85-13 engine are reported. The initial portion of the study was concerned with the calculation of the circumferential redistribution effects in the blade-free volumes forward and aft of the compression component. Although blade-free redistribution effects were estimated, no significant improvement over the parallel-compressor type solution in the prediction of total-pressure inlet distortion stability limit was obtained for the J85-13 engine. Further analysis was directed to identifying the rotor dynamic response to spatial circumferential distortions. Inclusion of the rotor dynamic response led to a considerable gain in the ability of the model to match the test data. The impact of variable stator loss on the prediction of the stability limit was evaluated. An assessment of measurement error on the derivation of the stage characteristics and predicted stability limit of the compressor was also performed.

Determination of the losses in a three-phase induction motor with speed controlled by the combined variation of the stator voltage and the rotor resistance; Determinacao das perdas de um motor de inducao trifasico com velocidade controlada pela variacao combinada da tensao do estator e resistencia rotorica

Energy Technology Data Exchange (ETDEWEB)

Almeida, Antonio Tadeu L. de; Sa, Jocelio Souza de; Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil)

1988-12-31

This work provides several expressions for determination of the losses in inductions motors of slip-rings in steady state; always as possible, the catalogue data of national manufacturers are used. In addition, the influence of the speed control through the combined variation of the stator voltage and rotor resistance in these losses is analysed. (author) 7 refs., 5 figs.

Prediction of Stator Terminal Voltages in IPMSM based on Static and Transient FEM Solution: Trade-off between Accuracy and Speed of Computation

Directory of Open Access Journals (Sweden)

Hichem Bouras

2017-12-01

Full Text Available The present work deals with the calculation of the time varying induced emf in permanent magnet synchronous machines from the numerical finite element solution. A review of the existing methods is presented; their intrinsic merits, in terms of accuracy and speed of computation, are compared. The currently used method, which relies on a weighting averaging procedure of the magnetic vector potential (MVP over the slot area in order to derive the winding flux linkage and the stator induced, has been modified to enhance its accuracy. An alternative method, which relies on the magnetic vector potential distribution along the mid airgap line, is proposed to carry out the same task. This approach has turned out to be very efficient since it enables a straightforward data handling, signal reconstruction, filtering and spectrum analysis of the relevant waveforms to be easily implemented in a single post-processing function. Finally, the relevance and efficiency of each method, in terms of accuracy and speed of computation, has been confirmed by the experimental results.

Monitoring of Rotor-Stator Interaction in Pump-Turbine Using Vibrations Measured with On-Board Sensors Rotating with Shaft

Directory of Open Access Journals (Sweden)

Cristian G. Rodriguez

2014-01-01

Full Text Available Current trends in design of pump-turbines have led into higher rotor-stator interaction (RSI loads over impeller-runner. These dynamic loads are of special interest having produced catastrophic failures in pump-turbines. Determining RSI characteristics facilitates the proposal of actions that will prevent these failures. Pressure measurements all around the perimeter of the impeller-runner are appropriate to monitor and detect RSI characteristics. Unfortunately most installed pump-turbines are not manufactured with in-built pressure sensors in appropriate positions to monitor RSI. For this reason, vibration measurements are the preferred method to monitor RSI in industry. Usually vibrations are measured in two perpendicular radial directions in bearings where valuable information could be lost due to bearing response. In this work, in order to avoid the effect of bearing response on measurement, two vibration sensors are installed rotating with the shaft. The RSI characteristics obtained with pressure measurements were compared to those determined using vibration measurements. The RSI characteristics obtained with pressure measurements were also determined using vibrations measured rotating with shaft. These RSI characteristics were not possible to be determined using the vibrations measured in guide bearing. Finally, it is recommended to measure vibrations rotating with shaft to detect RSI characteristics in installed pump-turbines as a more practical and reliable method to monitor RSI characteristics.

Switching EKF technique for rotor and stator resistance estimation in speed sensorless control of IMs

International Nuclear Information System (INIS)

Barut, Murat; Bogosyan, Seta; Gokasan, Metin

2007-01-01

High performance speed sensorless control of induction motors (IMs) calls for estimation and control schemes that offer solutions to parameter uncertainties as well as to difficulties involved with accurate flux/velocity estimation at very low and zero speed. In this study, a new EKF based estimation algorithm is proposed for the solution of both problems and is applied in combination with speed sensorless direct vector control (DVC). The technique is based on the consecutive execution of two EKF algorithms, by switching from one algorithm to another at every n sampling periods. The number of sampling periods, n, is determined based on the desired system performance. The switching EKF approach, thus applied, provides an accurate estimation of an increased number of parameters than would be possible with a single EKF algorithm. The simultaneous and accurate estimation of rotor, R r ' and stator, R s resistances, both in the transient and steady state, is an important challenge in speed sensorless IM control and reported studies achieving satisfactory results are few, if any. With the proposed technique in this study, the sensorless estimation of R r ' and R s is achieved in transient and steady state and in both high and low speed operation while also estimating the unknown load torque, velocity, flux and current components. The performance demonstrated by the simulation results at zero speed, as well as at low and high speed operation is very promising when compared with individual EKF algorithms performing either R r ' or R s estimation or with the few other approaches taken in past studies, which require either signal injection and/or a change of algorithms based on the speed range. The results also motivate utilization of the technique for multiple parameter estimation in a variety of control methods

Methods and apparatus for cooling wind turbine generators

Science.gov (United States)

Salamah, Samir A [Niskayuna, NY; Gadre, Aniruddha Dattatraya [Rexford, NY; Garg, Jivtesh [Schenectady, NY; Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Alplaus, NY; Carl, Jr., Ralph James

2008-10-28

A wind turbine generator includes a stator having a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis. A rotor is rotatable about the generator longitudinal axis, and the rotor includes a plurality of magnetic elements coupled to the rotor and cooperating with the stator windings. The magnetic elements are configured to generate a magnetic field and the stator windings are configured to interact with the magnetic field to generate a voltage in the stator windings. A heat pipe assembly thermally engaging one of the stator and the rotor to dissipate heat generated in the stator or rotor.

Modified Direct Torque Control of Three-Phase Induction Motor Drives with Low Ripple in Flux and Torque

Directory of Open Access Journals (Sweden)

Vinay KUMAR

2011-06-01

Full Text Available This paper proposes an algorithm for direct flux and torque controlled three phase induction motor drive systems. This method is based on control of slip speed and decoupled between amplitude and angle of reference stator flux for determining required stator voltage vector. In this proposes model, integrator unit is not required to generate the reference stator flux angle for calculating required stator voltage vector, hence it eliminates the initial values problems in real time. Within the given sampling time, flux as well as torque errors are controlled by stator voltage vector which is evaluated from reference stator flux. The direct torque control is achieved by reference stator flux angle which is generates from instantaneous slip speed angular frequency and stator flux angular frequency. The amplitude of the reference stator flux is kept constant at rated value. This technique gives better performance in three-phase induction motor than conventional technique. Simulation results for 3hp induction motor drive, for both proposed and conventional techniques, are presented and compared. From the results it is found that the stator current, flux linkage and torque ripples are decreased with proposed technique.

Dual-loop control strategy for DFIG-based Wind turbines under grid voltage disturbances

DEFF Research Database (Denmark)

Zhu, Rongwu; Chen, Zhe; Tang, Yi

2016-01-01

, but also decay the stator transient flux, and avoid the accumulation of the stator transient flux. Moreover, the proposed strategy can obtain nearly constant stator active power and electromagnetic torque, which may prolong the lifetime of the drive train. A case study on a typical 2-MW DFIG-based wind......For a multimegawatts doubly-fed induction generator (DFIG), the grid voltage disturbances may affect the stator flux and induce the transient stator flux, due to the direct connection of the stator and the grid. The accumulation of the transient stator flux caused by the variations of the stator...... turbine demonstrating the effectiveness of the proposed control methods is verified with simulations in MATLAB/Simulink. The proposed control methods are also experimentally validated using a scaled-down 7.5-kW DFIG. The simulation and experimental results clearly validate the effectiveness...

System and method for heating ferrite magnet motors for low temperatures

Science.gov (United States)

Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

2017-07-04

A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

System and method for heating ferrite magnet motors for low temperatures

Science.gov (United States)

Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

2018-05-08

A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

Influence of the rotor-stator interaction on the dynamic stresses of Francis runners

International Nuclear Information System (INIS)

Guillaume, R; Scolaro, D; Deniau, J L; Colombet, C

2012-01-01

Thanks to advances in computing capabilities and Computational Fluid Dynamics (CFD) techniques, it is now possible to calculate realistic unsteady pressure fields in Francis turbines. This paper will explain methods to calculate the structural loads and the dynamic behaviour in order to optimize the turbine design and maximize its reliability and lifetime. Depending on the operating conditions of a Francis turbine, different hydraulic phenomena may impact the mechanical behaviour of the structure. According to their nature, these highly variable phenomena should be treated differently and specifically in order to estimate the potential risks arising on submerged structures, in particular the runner. The operating condition studied thereafter is the point at maximum power with the maximum head. Under this condition, the runner is excited by only one dynamic phenomenon named the Rotor-Stator Interaction (RSI). The origin of the phenomenon is located on the radial gap of the turbine and is the source of pressure fluctuations. A fluid-structure analysis is performed to observe the influence of that dynamic pressure field on the runner behaviour. The first part of the paper deals with the unsteady fluid computation. The RSI phenomenon is totally unsteady so the fluid simulation must take into account the entire machine and its rotation movement, in order to obtain a dynamic pressure field. In the second part of the paper, a method suitable for the RSI study is developed. It is known that the fluctuating pressure in this gap can be described as a sum of spatial components. By evaluating these components in the CFD results and on the scale model, it is possible to assess the relevance of the numerical results on the whole runner. After this step, the numerical pressure field can be used as the dynamic load of the structure. The final part of the paper presentsthe mechanical finite element calculations. A modal analysis of the runner in water and a harmonic analysis of its

Vane clocking effects in an embedded compressor stage

Science.gov (United States)

Key, Nicole Leanne

The objective of this research was to experimentally investigate the effects of vane clocking, the circumferential indexing of adjacent vane rows with similar vane counts, in an embedded compressor stage. Experiments were performed in the Purdue 3-Stage Compressor, which consists of an IGV followed by three stages. The IGV, Stator 1, and Stator 2 have identical vane counts of 44, and the effects of clocking were studied on Stage 2. The clocking configuration that located the upstream vane wake on the Stator 2 leading edge was identified with total pressure measurements at the inlet to Stator 2 and confirmed with measurements at the exit of Stator 2. For both loading conditions, the total temperature results showed that there was no measurable change associated with vane clocking in the amount of work done on the flow. At design loading, the change in stage efficiency with vane clocking was 0.27 points between the maximum and minimum efficiency clocking configurations. The maximum efficiency configuration was the case where the Stator 1 wake impinged on the Stator 2 leading edge. This condition produced a shallower and thinner Stator 2 wake compared to the clocking configuration that located the wake in the middle of the Stator 2 passage. By locating the Stator 1 wake at the leading edge, it dampened the Stator 2 boundary layer response to inlet fluctuations associated with the Rotor 2 wakes. At high loading, the change in Stage 2 efficiency increased to 1.07 points; however, the maximum efficiency clocking configuration was the case where the Stator 1 wake passed through the middle of the downstream vane passage. At high loading, the flow physics associated with vane clocking were different than at design loading because the location of the Stator 1 wake fluid on the Stator 2 leading edge triggered a boundary layer separation on the suction side of Stator 2 producing a wider and deeper wake. Vane clocking essentially affects the amount of interaction between the

Torque ripple reduction in electric machines

Science.gov (United States)

Reddy, Patel Bhageerath; Huh, Kum-Kang; El-Refaie, Ayman Mohamed Fawzi; Galioto, Steven Joseph

2017-08-22

An electric machine, such as an Internal Permanent magnet or Synchronous Reluctance machine, having X phases, that includes a stator assembly, having M slots, with a stator core and stator teeth, that is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface that defines a cavity; and a rotor assembly, having N poles, disposed within the cavity which is configured to rotate about the longitudinal axis, wherein the rotor assembly includes a shaft, a rotor core located circumferentially around the shaft. The machine is configured such that a value k=M/(X*N) wherein k is a non-integer greater than about 1.3. The electric machine may alternatively, or additionally, include a non-uniformed gap between the exterior surface of the rotor spokes and the interior stator surface of the stator.

Disc rotors with permanent magnets for brushless DC motor

Science.gov (United States)

Hawsey, Robert A.; Bailey, J. Milton

1992-01-01

A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

Dovetail spoke internal permanent magnet machine

Science.gov (United States)

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-08-23

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

Levitated Duct Fan (LDF) Aircraft Auxiliary Generator

Science.gov (United States)

Eichenberg, Dennis J.; Emerson, Dawn C.; Gallo, Christopher A.; Thompson, William K.

2011-01-01

This generator concept includes a novel stator and rotor architecture made from composite material with blades attached to the outer rotating shell of a ducted fan drum rotor, a non-contact support system between the stator and rotor using magnetic fields to provide levitation, and an integrated electromagnetic generation system. The magnetic suspension between the rotor and the stator suspends and supports the rotor within the stator housing using permanent magnets attached to the outer circumference of the drum rotor and passive levitation coils in the stator shell. The magnets are arranged in a Halbach array configuration.

Offset-Free Direct Power Control of DFIG Under Continuous-Time Model Predictive Control

DEFF Research Database (Denmark)

Errouissi, Rachid; Al-Durra, Ahmed; Muyeen, S.M.

2017-01-01

This paper presents a robust continuous-time model predictive direct power control for doubly fed induction generator (DFIG). The proposed approach uses Taylor series expansion to predict the stator current in the synchronous reference frame over a finite time horizon. The predicted stator current...... is directly used to compute the required rotor voltage in order to minimize the difference between the actual stator currents and their references over the predictive time. However, as the proposed strategy is sensitive to parameter variations and external disturbances, a disturbance observer is embedded...... into the control loop to remove the steady-state error of the stator current. It turns out that the steady-state and the transient performances can be identified by simple design parameters. In this paper, the reference of the stator current is directly calculated from the desired stator active and reactive powers...

Monocoil reciprocating permanent magnet electric machine with self-centering force

Science.gov (United States)

Bhate, Suresh K. (Inventor); Vitale, Nicholas G. (Inventor)

1989-01-01

A linear reciprocating machine has a tubular outer stator housing a coil, a plunger and an inner stator. The plunger has four axially spaced rings of radially magnetized permanent magnets which cooperate two at a time with the stator to complete first or second opposite magnetic paths. The four rings of magnets and the stators are arranged so that the stroke of the plunger is independent of the axial length of the coil.

Improved Control Strategy for DFIG-based Wind Energy Conversion System during Grid Voltage Disturbances

DEFF Research Database (Denmark)

Zhu, Rongwu

electromagnetic torque during grid faults. Therefore, the virtual damping flux based strategy not only can help the DFIG achieve the LVRT requirement, but also can reduce the mechanical stress on the drive train. On the other hand, on the basis of the decaying characteristic of the stator flux, the passive...... flux based active damping strategy and the stator series resistance based passive damping strategy can help the DFIG to fulfill the LVRT requirement, and improve the DFIG performances. Besides the previous active and passive damping strategies, the modified power converter and DFIG configurations...... of the stator voltage can cause the transient stator flux, and then the transient stator flux may be enlarged due to the effects of the initial value. The amplitude of the transient flux is determined by both the instant and depth of stator voltage variation, and the decaying characteristic of the transient...

In vivo evaluation of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

Science.gov (United States)

Saeed, Diyar; Shalli, Shanaz; Fumoto, Hideyuki; Ootaki, Yoshio; Horai, Tetsuya; Anzai, Tomohiro; Zahr, Roula; Horvath, David J; Massiello, Alex L; Chen, Ji-Feng; Dessoffy, Raymond; Catanese, Jacquelyn; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

2010-06-01

Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14-91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.

High speed internal permanent magnet machine and method of manufacturing the same

Science.gov (United States)

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-09-13

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple permanent magnets for generating a magnetic field, which interacts with the stator magnetic field to produce torque. The permanent magnets are disposed between the stacks. The rotor assembly also includes multiple bottom wedges disposed on the bottom structures of the shaft and configured to hold the multiple stacks and the multiple permanent magnets.

Modeling and Performance of a Self-Excited Two-Phase Reluctance ...

African Journals Online (AJOL)

A self-excited two-phase reluctance generator (SETPRG) with balanced stator winding is presented. A unique balanced two-phase stator winding was designed with emphasis on obtaining a stator MMF waveform with minimum space harmonics. Then a mathematical model by which the dynamic behavior of the generator ...

Performance of claw-poled PM-stepping motor

International Nuclear Information System (INIS)

Liu, C.P.; Jeng, G.R.; Chen, W.C.; Tsai, M.C.; Wu, K.T.; Yao, Y.D.

2007-01-01

Present work is to analyze the performance of a permanent-magnetic (PM) stepping motor with claw poles by using the magnetic-circuit simulation technique. In this paper, we calculate the torque characteristics of the motor, such as the detent and the holding torques, and the step-position error by changing the gap between the upper and the lower stators and the staggered angle between the two stators. Through comparison of numerical data with experiment measurements, we found that the detent torque could be effectively reduced by increasing the stator-to-stator gap and further by decreasing the step-position error. Furthermore, the holding torque could be unchanged as the stator assemblage changed; however, it would be degenerated under the condition of low magnetization

Synthesis of nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} by absorption of ammonia into water-in-oil microemulsion in a rotor–stator reactor

Energy Technology Data Exchange (ETDEWEB)

Li, Yingwen; Wang, Hongrun; Arowo, Moses; Sun, Baochang, E-mail: sunbc@mail.buct.edu.cn; Chen, Jianfeng; Shao, Lei, E-mail: shaol@mail.buct.edu.cn [Beijing University of Chemical Technology, State Key Laboratory of Organic–Inorganic Composites (China)

2015-01-15

A gas-microemulsion reaction precipitation method was employed to prepare nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} by absorption of NH{sub 3} into water-in-oil (W/O) microemulsion in a rotor–stator reactor . The effects of different operating conditions including final pH of the microemulsion, reaction temperature, initial Ce{sup 3+} and Zr{sup 4+} concentration, rotation speed, and gas–liquid volumetric ratio were investigated. Nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} with an average diameter of about 5.5 nm, a specific surface area of 215.6 m{sup 2}/g and a size distribution of 4–8 nm was obtained under the optimum operating conditions. The as-prepared nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} was loaded with Au to prepare nano-Au/Ce{sub 0.5}Zr{sub 0.5}O{sub 2} catalyst which was subsequently used for CO oxidation test. CO conversion rate reached 100 % at room temperature, indicating high catalytic activity of the nano-Au/Ce{sub 0.5}Zr{sub 0.5}O{sub 2} catalyst.

Surface Temperature Measurements from a Stator Vane Doublet in a Turbine Engine Afterburner Flame Using a YAG:Tm Thermographic Phosphor

Science.gov (United States)

Eldridge, J. I.; Walker, D. G.; Gollub, S. L.; Jenkins, T. P.; Allison, S. W.

2015-01-01

Luminescence-based surface temperature measurements were obtained from a YAG:Tm-coated stator vane doublet exposed to the afterburner flame of a J85 test engine at University of Tennessee Space Institute (UTSI). The objective of the testing was to demonstrate that reliable surface temperatures based on luminescence decay of a thermographic phosphor producing short-wavelength emission could be obtained from the surface of an actual engine component in a high gas velocity, highly radiative afterburner flame environment. YAG:Tm was selected as the thermographic phosphor for its blue emission at 456 nm (1D23F4 transition) and UV emission at 365 nm (1D23H6 transition) because background thermal radiation is lower at these wavelengths, which are shorter than those of many previously used thermographic phosphors. Luminescence decay measurements were acquired using a probe designed to operate in the afterburner flame environment. The probe was mounted on the sidewall of a high-pressure turbine vane doublet from a Honeywell TECH7000 turbine engine coated with a standard electron-beam physical vapor deposited (EB-PVD) 200-m-thick TBC composed of yttria-stabilized zirconia (YSZ) onto which a 25-m-thick YAG:Tm thermographic phosphor layer was deposited by solution precursor plasma spray (SPPS). Spot temperature measurements were obtained by measuring luminescence decay times at different afterburner power settings and then converting decay time to temperature via calibration curves. Temperature measurements using the decays of the 456 and 365 nm emissions are compared. While successful afterburner environment measurements were obtained to about 1300C with the 456 nm emission, successful temperature measurements using the 365 nm emission were limited to about 1100C due to interference by autofluorescence of probe optics at short decay times.

Crystallographic and molecular dynamics analysis of loop motions unmasking the peptidoglycan-binding site in stator protein MotB of flagellar motor.

Directory of Open Access Journals (Sweden)

Cyril F Reboul

Full Text Available BACKGROUND: The C-terminal domain of MotB (MotB-C shows high sequence similarity to outer membrane protein A and related peptidoglycan (PG-binding proteins. It is believed to anchor the power-generating MotA/MotB stator unit of the bacterial flagellar motor to the peptidoglycan layer of the cell wall. We previously reported the first crystal structure of this domain and made a puzzling observation that all conserved residues that are thought to be essential for PG recognition are buried and inaccessible in the crystal structure. In this study, we tested a hypothesis that peptidoglycan binding is preceded by, or accompanied by, some structural reorganization that exposes the key conserved residues. METHODOLOGY/PRINCIPAL FINDINGS: We determined the structure of a new crystalline form (Form B of Helicobacter pylori MotB-C. Comparisons with the existing Form A revealed conformational variations in the petal-like loops around the carbohydrate binding site near one end of the β-sheet. These variations are thought to reflect natural flexibility at this site required for insertion into the peptidoglycan mesh. In order to understand the nature of this flexibility we have performed molecular dynamics simulations of the MotB-C dimer. The results are consistent with the crystallographic data and provide evidence that the three loops move in a concerted fashion, exposing conserved MotB residues that have previously been implicated in binding of the peptide moiety of peptidoglycan. CONCLUSION/SIGNIFICANCE: Our structural analysis provides a new insight into the mechanism by which MotB inserts into the peptidoglycan mesh, thus anchoring the power-generating complex to the cell wall.

Piezoelectric wave motor

Science.gov (United States)

Yerganian, Simon Scott

2001-07-17

A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

SSME Seal Test Program: Test results for sawtooth pattern damper seal

Science.gov (United States)

Childs, D. W.

1986-01-01

Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

A finite element-based algorithm for rubbing induced vibration prediction in rotors

Science.gov (United States)

Behzad, Mehdi; Alvandi, Mehdi; Mba, David; Jamali, Jalil

2013-10-01

In this paper, an algorithm is developed for more realistic investigation of rotor-to-stator rubbing vibration, based on finite element theory with unilateral contact and friction conditions. To model the rotor, cross sections are assumed to be radially rigid. A finite element discretization based on traditional beam theories which sufficiently accounts for axial and transversal flexibility of the rotor is used. A general finite element discretization model considering inertial and viscoelastic characteristics of the stator is used for modeling the stator. Therefore, for contact analysis, only the boundary of the stator is discretized. The contact problem is defined as the contact between the circular rigid cross section of the rotor and “nodes” of the stator only. Next, Gap function and contact conditions are described for the contact problem. Two finite element models of the rotor and the stator are coupled via the Lagrange multipliers method in order to obtain the constrained equation of motion. A case study of the partial rubbing is simulated using the algorithm. The synchronous and subsynchronous responses of the partial rubbing are obtained for different rotational speeds. In addition, a sensitivity analysis is carried out with respect to the initial clearance, the stator stiffness, the damping parameter, and the coefficient of friction. There is a good agreement between the result of this research and the experimental result in the literature.

Split Coil Forms for Rotary Transformers

Science.gov (United States)

Mclyman, C. W. T.

1982-01-01

Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.

Calculations of an unsteady flow through a hydraulic axial turbine with reference to interaction between stator and rotor; Instationaere Berechnung einer hydraulischen Axialturbine unter Beruecksichtigung der Interaktion zwischen Leit- und Laufrad

Energy Technology Data Exchange (ETDEWEB)

Bauer, C.

2001-07-01

The objective of this study is the development of an algorithm enabling coupling of nonmatching computational grids to carry out calculations of an unsteady flow through a hydraulic axial turbine with reference to interaction between stator and rotor. The algorithm should offer the possibility to operate the computational grids in a fixed position relative to each other as well as in relative movement. Furthermore, the calculation should be feasible with separate grids in parallel and different frames of reference. Employing selected examples this method is investigated in detail the results are compared with performed measurements. The unsteady numerical examination of the coupling process is carried out with different examples; especially the interaction effects between stator, rotor and draft tube of a hydraulic axial turbine are observed. In addition, the effect of tip clearance of the mean flow is described. Extensive model tests using the axial turbine have been performed at the Institute for Fluid Mechanics and Hydraulic Machinery, IHS. Flow time dependent velocities have been measured with a Laser Doppler Velocimeter placed at midspan of the blading. Periodical changes in static pressure have been recorded at different locations near the wall of the turbine casing. These measurements serve as reference for the comparison with results derived from the unsteady calculations. The confrontation of the time-dependent fluctuations of the flow quantities and the calculation of the efficiency of the turbine resulting from the simulation results allow a comparison in absolute terms. (orig.) [German] Fuer die instationaere Berechnung einer hydraulischen Axialturbine unter Beruecksichtigung der Interaktion zwischen Leit- und Laufrad wird ein Algorithmus zum Koppeln von nichtpassenden Berechnungsnetzen entwickelt. Diese Berechnungsnetze sollen zueinander ortsfest sein oder auch eine Relativbewegung zueinander haben koennen. Sie sollen ausserdem und in unterschiedlichen

Coupled 2-dimensional cascade theory for noise and unsteady aerodynamics of blade row interaction in turbofans. Volume 1: Theory development and parametric studies

Science.gov (United States)

Hanson, Donald B.

1994-01-01

Typical analytical models for interaction between rotor and stator in a turbofan analyze the effect of wakes from the rotor impinging on the stator, producing unsteady loading, and thereby generating noise. Reflection/transmission characteristics of the rotor are sometimes added in a separate calculation. In those models, there is a one-to-one relationship between wake harmonics and noise harmonics; that is, the BPF (blade passing frequency) wake harmonic causes only the BPF noise harmonic, etc. This report presents a more complete model in which flow tangency boundary conditions are satisfied on two cascades in relative motion for several harmonics simultaneously. By an extension of S.N. Smith's code for two dimensional flat plate cascades, the noise generation/frequency scattering/blade row reflection problem is solved in a single matrix inversion. It is found that the BPF harmonic excitation of the stator scatters considerable energy in the higher BPF harmonics due to relative motion between the blade rows. Furthermore, when swirl between the rotor and stator is modeled, a 'mode trapping' effect occurs which explains observations on fans operating at rotational speeds below BFP cuton: the BPF mode amplifies between blade rows by multiple reflections but cannot escape to the inlet and exit ducts. However, energy scattered into higher harmonics does propagate and dominates the spectrum at two and three times BPF. This report presents the complete derivation of the theory, comparison with a previous (more limited) coupled rotor/stator interaction theory due to Kaji and Okazaki, exploration of the mode trapping phenomenon, and parametric studies showing the effects of vane/blade ratio and rotor/stator interaction. For generality, the analysis applies to stages where the rotor is either upstream or downstream of the stator and to counter rotation stages. The theory has been coded in a FORTRAN program called CUP2D, documented in Volume 2 of this report. It is

Mechanics of torque generation in the bacterial flagellar motor.

Science.gov (United States)

Mandadapu, Kranthi K; Nirody, Jasmine A; Berry, Richard M; Oster, George

2015-08-11

The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well established that the passage of ions down a transmembrane gradient through the stator complex provides the energy for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify roles for two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, whereas steric forces comprise the actual "power stroke." Specifically, we propose that ion-induced conformational changes about a proline "hinge" residue in a stator α-helix are directly responsible for generating the power stroke. Our model predictions fit well with recent experiments on a single-stator motor. The proposed model provides a mechanical explanation for several fundamental properties of the flagellar motor, including torque-speed and speed-ion motive force relationships, backstepping, variation in step sizes, and the effects of key mutations in the stator.

Rotating flux compressor for energy conversion

International Nuclear Information System (INIS)

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

Electromagnetic pump

International Nuclear Information System (INIS)

Ito, Koji; Suetake, Norio; Aizawa, Toshie; Nakasaki, Masayoshi

1998-01-01

The present invention provides an electromagnetic pump suitable to a recycling pump for liquid sodium as coolants of an FBR type reactor. Namely, a stator module of the electromagnetic pump of the present invention comprises a plurality of outer laminate iron core units and outer stator modules stacked alternately in the axial direction. With such a constitution, even a long electromagnetic pump having a large number of outer stator coils can be manufactured without damaging electric insulation of the outer stator coils. In addition, the inner circumferential surface of the outer laminate iron cores is urged and brought into contact with the outer circumferential surface of the outer duct by an elastic material. With such a constitution, Joule loss heat generated in the outer stator coils and internal heat generated in the outer laminate iron cores can be released to an electroconductive fluid flowing the inner circumference of the outer duct by way of the outer duct. (I.S.)

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

Science.gov (United States)

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.

Estimation of the iron loss in deep-sea permanent magnet motors considering seawater compressive stress.

Science.gov (United States)

Xu, Yongxiang; Wei, Yanyu; Zou, Jibin; Li, Jianjun; Qi, Wenjuan; Li, Yong

2014-01-01

Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM). The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress.

Estimation of the Iron Loss in Deep-Sea Permanent Magnet Motors considering Seawater Compressive Stress

Directory of Open Access Journals (Sweden)

Yongxiang Xu

2014-01-01

Full Text Available Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM. The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress.

Substantially parallel flux uncluttered rotor machines

Science.gov (United States)

Hsu, John S.

2012-12-11

A permanent magnet-less and brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by polyphase alternating currents. An uncluttered rotor is positioned within the magnetic rotating field and is spaced apart from the stator. An excitation core is spaced apart from the stator and the uncluttered rotor and magnetically couples the uncluttered rotor. The brushless excitation source generates a magnet torque by inducing magnetic poles near an outer peripheral surface of the uncluttered rotor, and the stator currents also generate a reluctance torque by a reaction of the difference between the direct and quadrature magnetic paths of the uncluttered rotor. The system can be used either as a motor or a generator

Hermetically sealed superconducting magnet motor

Science.gov (United States)

DeVault, Robert C.; McConnell, Benjamin W.; Phillips, Benjamin A.

1996-01-01

A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit.

Modélisation du bruit à large bande de soufflantes de turboréacteurs.

OpenAIRE

Reboul , Gabriel

2010-01-01

This report presents several methodologies aiming to predict broadband noise generatedby the interaction between the rotor and the stator of a turbofan. The main objective is toobtain a complete prediction procedure from the acoustic sources generation to the far fieldnoise radiation. As a first step, the rotor-stator mechanism is studied as the interaction betweena homogeneous and isotropic turbulence (HIT) and an isolated airfoil. Then, the ductedrotor/stator interaction case is treated. Fi...

Multiphysics Modeling of an Permanent Magnet Synchronous Machine

Directory of Open Access Journals (Sweden)

MARTIS Claudia

2012-10-01

Full Text Available This paper analyzes the noise and vibration in PMSMs. There are three types of vibrations in electrical machines: electromagnetic,mechanical and aerodynamic. Electromagnetic force are the main cause of noise and vibration in PMSMs. It is very important to calculate precisely the natural frequencies of the stator system. If oneradial force (which are the main cause for electromagnetic vibration has the frequency close to the natural frequency of the stator system for the same order of vibrational mode, then this force canproduce dangerous vibration in the stator system. The natural frequencies for a stator system of a PMSM have been calculated. Finally a Structural Analysis has been made , pointing out the radialdisplacement and stress for the chosen PMSM .

Microgrid Restraining Strategy Based on Improved DC Grid Connected DFIG Torque Ripple

Science.gov (United States)

Fei, Xia; Yang, Zhixiong; Zongze, Xia

2017-05-01

Aiming to the voltage of the stator side is generated by the modulation of the SSC in the improved topology, especially under the circumstance with the asymmTeric fault of stator side, DFIG’s electromagnTeic torque, amplifies ripple of grid-connected power for the grid side. The novel control mTehod suitable to stator side converter and rotor side converter based on reduced-order resonant controller (RORC) is proposed in this thesis, DFIG’s torque and output power performance are improved. Under the RORC control conditions the transfer functions of stator current and torque control system are established, the amplitude characteristic and the system stability of RORC control are analysed. The simulation results in Matlab/Simulink verify the correctness and validity of the proposed mTehod.

Wave propagations of curvilinear motors driven by partially laminated piezoelectric actuators

International Nuclear Information System (INIS)

Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Muensit, Supasarote; Tzou, Horn-Sen

2008-01-01

A piezoelectric arc stator is the key component delivering driving actions to an ultrasonic curvilinear motor. The arc stator drives the rotor along the arc structure to any specific angular position. Usually conventional stators in ultrasonic motors are fully bounded with piezoelectric patch actuators. To reduce production costs while maintaining similar driving characteristics, an arc stator partially bonded with piezoelectric actuators is proposed and its dynamic characteristics are analyzed in this study. The effect of actuator locations on the wave propagation is investigated. Both analytical and finite element results demonstrate similar dynamic responses. That is, the response of the wave propagation depends on specific locations of piezoelectric actuators. One of the two configurations investigated shows that the partially laminated piezoelectric actuator pattern can also generate rather steady traveling waves on the stator with consistent wave amplitude. This implies that the partially laminated actuator technique could be an alternative actuator pattern to the fully laminated actuators in the design of ultrasonic curvilinear motors or other finite-length ultrasonic motors

A New Power-Factor-Based Vector Control Method for Sensorless Drive of Permanent-Magnet Synchronous Motors

Science.gov (United States)

Shinnaka, Shinji

As a simple vector control method for sensorless drives of permanent-magnet synchronous motors, the so-called “Power-Factor-Based (PFB) Vector Control Method” has been proposed. The conventional PFB method directly estimates the phase of the quasi-optimal stator current through a control of the power factor phase, instead of the estimation of the rotor phase. The stator current is controlled in the current reference frame whose secondary axis phase is the same as the stator current phase. This paper proposes a new PEB method where the stator current is controlled in the voltage reference frame whose secondary axis phase is the same as the voltage phase rather than the current phase. It is shown that the similar quasi-optimal stator current control can be attained through the current control with appropriate current commands taking the power factor phase into account. This paper also shows a practical method for generating the current commands and a practical guideline for the design parameters of the new PFB method.

Influence of winding construction on starter-generator thermal processes

Science.gov (United States)

Grachev, P. Yu; Bazarov, A. A.; Tabachinskiy, A. S.

2018-01-01

Dynamic processes in starter-generators features high winding are overcurrent. It can lead to insulation overheating and fault operation mode. For hybrid and electric vehicles, new high efficiency construction of induction machines windings is proposed. Stator thermal processes need be considered in the most difficult operation modes. The article describes construction features of new compact stator windings, electromagnetic and thermal models of processes in stator windings and explains the influence of innovative construction on thermal processes. Models are based on finite element method.

Permanent magnet machine with windings having strand transposition

Science.gov (United States)

Qu, Ronghai; Jansen, Patrick Lee

2009-04-21

This document discusses, among other things, a stator with transposition between the windings or coils. The coils are free from transposition to increase the fill factor of the stator slots. The transposition at the end connections between an inner coil and an outer coil provide transposition to reduce circulating current loss. The increased fill factor reduces further current losses. Such a stator is used in a dual rotor, permanent magnet machine, for example, in a compressor pump, wind turbine gearbox, wind turbine rotor.

Brushless dc motor uses electron beam switching tube as commutator

Science.gov (United States)

Studer, P.

1965-01-01

Electron beam switching tube eliminates physical contact between rotor and stator in brushless dc motor. The tube and associated circuitry control the output of a dc source to sequentially energize the motor stator windings.

Quantitative control of a rotary carbon nanotube motor under temperature stimulus

International Nuclear Information System (INIS)

Cai, Kun; Wan, Jing; Shi, Jiao; Qin, Qing H

2016-01-01

Since a double-walled carbon nanotube (DWCNT)-based rotary motor driven by a uniform temperature field was proposed in 2014, how to control quantitatively the rotation of the rotor is still an open question. In this work, we present a mathematical relationship between the rotor’s speed and interaction energy. Essentially, the increment of interaction energy between the rotor and the stator(s) determines the rotor’s rotational speed, whereas the type of radial deviation of an end carbon atom on the stator determines the rotational direction. The rotational speed of the rotor can be specified by adjusting temperature and radial deviation of an end carbon atom on the stator. It is promising for designing a controllable temperature-driven rotary motor based on DWCNTs with length of few nanometers only. (paper)

Design and analysis of EI core structured transverse flux linear reluctance actuator

OpenAIRE

FENERCİOĞLU, AHMET; AVŞAR, YUSUF

2015-01-01

In this study, an EI core linear actuator is proposed for horizontal movement systems. It is a transverse flux linear switched reluctance motor designed with an EI core structure geometrically. The actuator is configured into three phases and at a 6/4 pole ratio, and it has a stationary active stator along with a sliding passive translator. The stator consists of E cores and the translator consists of I cores. The actuator has a yokeless design because the stator and translator have no back i...

RTOD- RADIAL TURBINE OFF-DESIGN PERFORMANCE ANALYSIS

Science.gov (United States)

Glassman, A. J.

1994-01-01

The RTOD program was developed to accurately predict radial turbine off-design performance. The radial turbine has been used extensively in automotive turbochargers and aircraft auxiliary power units. It is now being given serious consideration for primary powerplant applications. In applications where the turbine will operate over a wide range of power settings, accurate off-design performance prediction is essential for a successful design. RTOD predictions have already illustrated a potential improvement in off-design performance offered by rotor back-sweep for high-work-factor radial turbines. RTOD can be used to analyze other potential performance enhancing design features. RTOD predicts the performance of a radial turbine (with or without rotor blade sweep) as a function of pressure ratio, speed, and stator setting. The program models the flow with the following: 1) stator viscous and trailing edge losses; 2) a vaneless space loss between the stator and the rotor; and 3) rotor incidence, viscous, trailing-edge, clearance, and disk friction losses. The stator and rotor viscous losses each represent the combined effects of profile, endwall, and secondary flow losses. The stator inlet and exit and the rotor inlet flows are modeled by a mean-line analysis, but a sector analysis is used at the rotor exit. The leakage flow through the clearance gap in a pivoting stator is also considered. User input includes gas properties, turbine geometry, and the stator and rotor viscous losses at a reference performance point. RTOD output includes predicted turbine performance over a specified operating range and any user selected flow parameters. The RTOD program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 series computer with a central memory requirement of approximately 100K of 8 bit bytes. The RTOD program was developed in 1983.

Novel maglev pump with a combined magnetic bearing.

Science.gov (United States)

Onuma, Hiroyuki; Murakami, Michiko; Masuzawa, Toru

2005-01-01

The newly developed pump is a magnetically levitated centrifugal blood pump in which active and passive magnetic bearings are integrated to construct a durable ventricular assist device. The developed maglev centrifugal pump consists of an active magnetic bearing, a passive magnetic bearing, a levitated impeller, and a motor stator. The impeller is set between the active magnetic bearing and the motor stator. The active magnetic bearing uses four electromagnets to control the tilt and the axial position of the impeller. The radial movement of the levitated impeller is restricted with the passive stability dependent upon the top stator and the passive permanent magnetic bearing to reduce the energy consumption and the control system complexity. The top stator was designed based upon a magnetic field analysis to develop the maglev pump with sufficient passive stability in the radial direction. By implementing this analysis design, the oscillating amplitude of the impeller in the radial direction was cut in half when compared with the simple shape stator. This study concluded that the newly developed maglev centrifugal pump displayed excellent levitation performance and sufficient pump performance as a ventricular assist device.

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

DEFF Research Database (Denmark)

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

1996-01-01

Methods for estimation of the parameters in the electrical equivalent diagram for the induction motor, based on special designed experiments, are given. In all experriments two of the three phases are given the same potential, i.e., no net torque is generatedand the motor is at standstill. Input...... and 3) the referred rotor rotor resistance and magnetizing inductance. The method developed in the two last experiments is independent of the inverter nonlinearity. New methods for system identification concerning saturation of the magnetic flux are given and a reference value for the flux level...... to the system is the reference values for the stator voltages given as duty cycles for the Pulse With Modulated power device. The system output is the measured stator currents. Three experiments are describedgiving respectively 1) the stator resistance and inverter parameters, 2) the stator transient inductance...

PD-pulse characteristics in rotating machine insulation

DEFF Research Database (Denmark)

Holbøll, Joachim; Henriksen, Mogens; Jensen, A

1994-01-01

In this paper results are presented from investigations on partial discharges (PD) in insulation systems, resembling the stator insulation in high voltage rotating machines. A model, simulating a stator winding in a slot, has been developed, consisting of simple rotating machine insulation test...... bars with epoxy/mica insulation, mounted between steel sheets forming a dot, in order to investigate the fundamental behaviour of PD in insulation defects in epoxy/mica insulation and the characteristics of the resulting electrical pulses. Stator slot couplers (SSC) were used to detect pulses coming...

Double U-Core Switched Reluctance Machine

DEFF Research Database (Denmark)

2016-01-01

The present invention relates to an electrical machine stator comprising a plurality of stator segments (131,132,133), each segment comprises a first U-core and a second U-core wound with a winding, where the winding being arranged with at least one coil turn, each coil turn comprises a first axial......(s), wherein the first U-core and the second U-core are located adjacent to each other, whereby the winding spans the first and second U-cores. The invention also relates to a SRM machine with a stator mentioned above and a rotor....

Modelling and analysis of an open-loop induction motor drive ...

Indian Academy of Sciences (India)

The objective of this paper is to study the influence of inverter dead-time on steady as well as dynamic operation of an .... Modelling of IM drive incorporating dead-time effect. 127 ...... stator resistance in series with the stator reactance). Hence.

A Sensor-less Method for Online Thermal Monitoring of Switched Reluctance Machine

DEFF Research Database (Denmark)

Wang, Chao; Liu, Hui; Liu, Xiao

2015-01-01

Stator winding is one of the most vulnerable parts in Switched Reluctance Machine (SRM), especially under thermal stresses during frequently changing operation circumstances and susceptible heat dissipation conditions. Thus real-time online thermal monitoring of the stator winding is of great sig...

Optimal Design Solutions for Permanent Magnet Synchronous Machines

Directory of Open Access Journals (Sweden)

POPESCU, M.

2011-11-01

Full Text Available This paper presents optimal design solutions for reducing the cogging torque of permanent magnets synchronous machines. A first solution proposed in the paper consists in using closed stator slots that determines a nearly isotropic magnetic structure of the stator core, reducing the mutual attraction between permanent magnets and the slotted armature. To avoid complications in the windings manufacture technology the stator slots are closed using wedges made of soft magnetic composite materials. The second solution consists in properly choosing the combination of pole number and stator slots number that typically leads to a winding with fractional number of slots/pole/phase. The proposed measures for cogging torque reduction are analyzed by means of 2D/3D finite element models developed using the professional Flux software package. Numerical results are discussed and compared with experimental ones obtained by testing a PMSM prototype.

Turbofan noise generation. Volume 1: Analysis

Science.gov (United States)

Ventres, C. S.; Theobald, M. A.; Mark, W. D.

1982-01-01

Computer programs were developed which calculate the in-duct acoustic modes excited by a fan/stator stae operating at subsonic tip speed. Three noise source mechanisms are included: (1) sound generated by the rotor blades interacting with turbulence ingested into, or generated within, the inlet duct; (2) sound generated by the stator vanes interacting with the turbulent wakes of the rotors blades; and (3) sound generated by the stator vanes interacting with the mean velocity deficit wakes of the rotor blades. The fan/stator stage is modeled as an ensemble of blades and vanes of zero camber and thickness enclosed within an infinite hard-walled annular duct. Turbulence drawn into or generated within the inlet duct is modeled as nonhomogeneous and anisotropic random fluid motion, superimposed upon a uniform axial mean flow, and convected with that flow. Equations for the duct mode amplitudes, or expected values of the amplitudes, are derived.

Performance analysis of variable speed multiphase induction motor with pole phase modulation

Directory of Open Access Journals (Sweden)

Liu Huijuan

2016-09-01

Full Text Available The pole phase modulation (PPM technique is an effective method to extend speed range and torque capabilities for an integrated starter and hybrid electric vehicles applications. In this paper, the five pole-phase combination types of a multiphase induction motor (IM with 36 stator slots and 36 stator conductors are presented and compared quantitatively by using the time-stepping finite element method (TS-FEM. The 36 stator conductors of the proposed multiphase IM are fed by a 36 leg inverter and the current phase angle and amplitude of each stator conductor can be controlled independently. This paper focuses on the winding connection, the PPM technique and the performance comparative analysis of each pole-phase combination types of the proposed multiphase IM. The flux distribution, air-gap flux density, output torque, core losses and efficiency of five pole-phase combination types have been investigated.

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, H.S.

1984-07-31

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level. 6 figs.

Dual power, constant speed electric motor system

Science.gov (United States)

Kirschbaum, Herbert S.

1984-01-01

A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level.

Modeling, control and fault diagnosis of an isolated wind energy conversion system with a self-excited induction generator subject to electrical faults

International Nuclear Information System (INIS)

Attoui, Issam; Omeiri, Amar

2014-01-01

Highlights: • A new model of the SEIG is developed to simulate both the rotor and stator faults. • This model takes iron loss, main flux and cross flux saturation into account. • A new control strategy based on Fractional-Order Controller (FOC) is proposed. • The control strategy is developed for the control of the wind turbine speed. • An on-line diagnostic procedure based on the stator currents analysis is presented. - Abstract: In this paper, a contribution to modeling and fault diagnosis of rotor and stator faults of a Self-Excited Induction Generator (SEIG) in an Isolated Wind Energy Conversion System (IWECS) is proposed. In order to control the speed of the wind turbine, while basing on the linear model of wind turbine system about a specified operating point, a new Fractional-Order Controller (FOC) with a simple and practical design method is proposed. The FOC ensures the stability of the nonlinear system in both healthy and faulty conditions. Furthermore, in order to detect the stator and rotor faults in the squirrel-cage self-excited induction generator, an on-line fault diagnostic technique based on the spectral analysis of stator currents of the squirrel-cage SEIG by a Fast Fourier Transform (FFT) algorithm is used. Additionally, a generalized model of the squirrel-cage SEIG is developed to simulate both the rotor and stator faults taking iron loss, main flux and cross flux saturation into account. The efficiencies of generalized model, control strategy and diagnostic procedure are illustrated with simulation results

A class of flux observers for doubly-fed induction generators used in small power wind generation systems

DEFF Research Database (Denmark)

Lascu, C.; Boldea, I.; Blaabjerg, Frede

2013-01-01

This paper investigates a family of stator and rotor flux observers for sensorless operation of doubly-fed induction generators (DFIG). Four stator flux observer topologies are described and compared. All proposed schemes use the voltage and current models connected in parallel or in series...

Torque ripple reduction of brushless DC motor with harmonic current injection based on integral terminal sliding mode control

DEFF Research Database (Denmark)

Boroujeni, Mojtaba Shirvani; Markadeh, Gholamreza Arab; Soltani, Jafar

2018-01-01

Brushless Harmonic current injection to the stator windings is one of the most effective methods for torque ripple reduction of brushless DC motors. Because of multi harmonic contents of the stator currents, the conventional methods based on rotational reference frame cannot be used to calculate...

Self-Commissioning for sensorless Field Oriented Control of PM motors

DEFF Research Database (Denmark)

Rasmussen, Henrik

2004-01-01

currents. Inverter parameters, stator resistance and inductance are measured at stand-still before the initial start-up of the drive. The strength of the permanent magnet is measured during a initial manual start-up of the drive. The measured parameters are used in a field oriented control system......Methods for estimation of the parameters in the inverter and the PM motor, based on special designed experiments, are given. Input to the system is the reference values for the stator voltages given as duty cycles for the Pulse With Modulated power device. The system output is the measured stator...

Self-commisioning for Sensorless Field Oriented Control of PM Motors

DEFF Research Database (Denmark)

Rasmussen, Henrik

2004-01-01

currents. Inverter parameters, stator resistance and inductance are measured at stand-still before the initial start-up of the drive. The strength of the permanent magnet is measured during a initial manual start-up of the drive. The measured parameters are used in a field oriented control system......Methods for estimation of the parameters in the inverter and the PM motor, based on special designed experiments, are given. Input to the system is the reference values for the stator voltages given as duty cycles for the Pulce With Modulated power device. The system output is the measured stator...

Self-commissioning for sensorless Field Oriented Control of PM Motors

DEFF Research Database (Denmark)

Rasmussen, Henrik

2004-01-01

currents. Inverter parameters, stator resistance and inductance are measured at stand-still before the initial start-up of the drive. The strength of the permanent magnet is measured during a initial manual start-up of the drive. The measured parameters are used in a field oriented control system......Methods for estimation of the parameters in the inverter and the PM motor, based on special designed experiments, are given. Input to the system is the reference values for the stator voltages given as duty cycles for the Pulse With Modulated power device. The system output is the measured stator...

Dynamic Thermal Analysis of DFIG Rotor-side Converter during Balanced Grid Fault

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2014-01-01

and the rotor voltage during the balanced grid fault is firstly addressed. By using the traditional demagnetizing control, the damping of the stator flux and the safety operation area are theoretically evaluated with various amounts of demagnetizing current. It is observed that the higher demagnetizing current...... leads to faster stator flux damping and lower induced rotor voltage, but it brings higher loss as well as the thermal cycling of the power device. Based on the simulation of the stator flux evolution and the thermal behavior of each power semiconductor, it is concluded that there is a trade...

Extended Park's transformation for 2×3-phase synchronous machine and converter phasor model with representation of AC harmonics

DEFF Research Database (Denmark)

Knudsen, Hans

1995-01-01

A model of the 2×3-phase synchronous machine is presented using a new transformation based on the eigenvectors of the stator inductance matrix. The transformation fully decouples the stator inductance matrix, and this leads to an equivalent diagram of the machine with no mutual couplings...

An Enhanced LVRT Scheme for DFIG-based WECSs under Both Balanced and Unbalanced Grid Voltage Sags

DEFF Research Database (Denmark)

Mohammadi, Jafar; Afsharnia, Saeed; Ebrahimzadeh, Esmaeil

2017-01-01

reactive power into the grid. The passive compensator is based on a three-phase stator damping resistor (SDR) located in series with the stator windings. The proposed scheme decreases the negative effects of grid voltage sags in the DFIG system including the rotor over-currents, electromagnetic torque...

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Model and performance of current sensor observers for a doubly fed induction generator

DEFF Research Database (Denmark)

Li, Hui; Yang, Chao; Hu, Yaogang

2014-01-01

. A stator and rotor current observer model, which is based on the state-space models of doubly fed induction generators, is then derived by using the stator and rotor voltage signals as inputs. To demonstrate the effectiveness of the proposed current observer, its dynamic performance is simulated using...

Flux Concentration and Pole Shaping in a Single Phase Hybrid Switched Reluctance Motor Drive

DEFF Research Database (Denmark)

Jakobsen, Uffe; Lu, Kaiyuan

2010-01-01

The single phase hybrid switched reluctance motor (HSRM) may be a good candidate for low-cost drives used for pump applications. This paper presents a new design of the HSRM with improved starting torque achieved by stator pole shaping, and a better arrangement of the embedded stator permanent...

Bi Input-extended Kalman filter based estimation technique for speed-sensorless control of induction motors

International Nuclear Information System (INIS)

Barut, Murat

2010-01-01

This study offers a novel extended Kalman filter (EKF) based estimation technique for the solution of the on-line estimation problem related to uncertainties in the stator and rotor resistances inherent to the speed-sensorless high efficiency control of induction motors (IMs) in the wide speed range as well as extending the limited number of states and parameter estimations possible with a conventional single EKF algorithm. For this aim, the introduced estimation technique in this work utilizes a single EKF algorithm with the consecutive execution of two inputs derived from the two individual extended IM models based on the stator resistance and rotor resistance estimation, differently from the other approaches in past studies, which require two separate EKF algorithms operating in a switching or braided manner; thus, it has superiority over the previous EKF schemes in this regard. The proposed EKF based estimation technique performing the on-line estimations of the stator currents, the rotor flux, the rotor angular velocity, and the load torque involving the viscous friction term together with the rotor and stator resistance is also used in the combination with the speed-sensorless direct vector control of IM and tested with simulations under the challenging 12 scenarios generated instantaneously via step and/or linear variations of the velocity reference, the load torque, the stator resistance, and the rotor resistance in the range of high and zero speed, assuming that the measured stator phase currents and voltages are available. Even under those variations, the performance of the speed-sensorless direct vector control system established on the novel EKF based estimation technique is observed to be quite good.

Bi Input-extended Kalman filter based estimation technique for speed-sensorless control of induction motors

Energy Technology Data Exchange (ETDEWEB)

Barut, Murat, E-mail: muratbarut27@yahoo.co [Nigde University, Department of Electrical and Electronics Engineering, 51245 Nigde (Turkey)

2010-10-15

This study offers a novel extended Kalman filter (EKF) based estimation technique for the solution of the on-line estimation problem related to uncertainties in the stator and rotor resistances inherent to the speed-sensorless high efficiency control of induction motors (IMs) in the wide speed range as well as extending the limited number of states and parameter estimations possible with a conventional single EKF algorithm. For this aim, the introduced estimation technique in this work utilizes a single EKF algorithm with the consecutive execution of two inputs derived from the two individual extended IM models based on the stator resistance and rotor resistance estimation, differently from the other approaches in past studies, which require two separate EKF algorithms operating in a switching or braided manner; thus, it has superiority over the previous EKF schemes in this regard. The proposed EKF based estimation technique performing the on-line estimations of the stator currents, the rotor flux, the rotor angular velocity, and the load torque involving the viscous friction term together with the rotor and stator resistance is also used in the combination with the speed-sensorless direct vector control of IM and tested with simulations under the challenging 12 scenarios generated instantaneously via step and/or linear variations of the velocity reference, the load torque, the stator resistance, and the rotor resistance in the range of high and zero speed, assuming that the measured stator phase currents and voltages are available. Even under those variations, the performance of the speed-sensorless direct vector control system established on the novel EKF based estimation technique is observed to be quite good.

Theoretical and Experimental Research of Synchronous Reluctance Motor

Science.gov (United States)

Dobriyan, R.; Vitolina, S.; Lavrinovicha, L.; Dirba, J.

2017-10-01

The paper presents the research on evaluation of accuracy of magnetic field calculations of synchronous reluctance motor in comparison with the results obtained in experiments. Magnetic field calculations are performed with the finite element method to determine values of the magnetic flux and electromagnetic torque according to the current value in motor stator and load angle between the rotor direct-axis and axis of stator magnetomotive force (MMF). Experimental values of magnetic flux and electromagnetic torque are obtained on motor with locked rotor while equivalent direct current is applied to the stator windings. The research shows that the results obtained from the magnetic field calculations coincide well with the experimental data.

Numerical simulation of explosive magnetic cumulative generator EMG-720

Energy Technology Data Exchange (ETDEWEB)

Deryugin, Yu N; Zelenskij, D K; Kazakova, I F; Kargin, V I; Mironychev, P V; Pikar, A S; Popkov, N F; Ryaslov, E A; Ryzhatskova, E G [All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation)

1997-12-31

The paper discusses the methods and results of numerical simulations used in the development of a helical-coaxial explosive magnetic cumulative generator (EMG) with the stator up to 720 mm in diameter. In the process of designing, separate units were numerically modeled, as was the generator operation with a constant inductive-ohmic load. The 2-D processes of the armature acceleration by the explosion products were modeled as well as those of the formation of the sliding high-current contact between the armature and stator`s insulated turns. The problem of the armature integrity in the region of the detonation waves collision was numerically analyzed. 8 figs., 2 refs.

Dynamical analysis of a flywheel-superconducting bearing with a moving magnet support

International Nuclear Information System (INIS)

Sivrioglu, Selim; Nonami, Kenzo

2003-01-01

A lateral stiffness improvement approach based on a moving magnet support is developed to reduce the vibration of a flywheel rotor-high temperature superconductor (HTS) bearing. A flywheel rotor levitated with an HTS bearing is modelled and then analysed with a moving stator magnet placed above the rotor. A dynamic support principle is introduced based on moving the stator magnet in anti-phase with the rotor displacement for small variations. A complete dynamical equation of the flywheel rotor is derived including gyroscopic and imbalance effects. The simulation results showed that the dynamic support of the flywheel rotor with additional stator magnet movements decreases the vibration of the flywheel rotor considerably

characteristics of structural breakdown in plastic concrete and their

African Journals Online (AJOL)

Dr Obe

observed as shearing proceeded. ANALYSIS OF THIXOTROPIC BREAKDOWN OF. CONCRETE. As the cup rotates on application of rotational shear stress, the stator also tends to rotate due to the viscous drag transmitted by the mix. The stator continues to rotate until the resistance registered by the torque arm becomes ...

Variable stator radial turbine

Science.gov (United States)

Rogo, C.; Hajek, T.; Chen, A. G.

1984-01-01

A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

New concepts and new design of permanent maglev rotary artificial heart blood pumps.

Science.gov (United States)

Qian, K X; Zeng, P; Ru, W M; Yuan, H Y

2006-05-01

According to tradition, permanent maglev cannot achieve stable equilibrium. The authors have developed, to the contrary, two stable permanent maglev impeller blood pumps. The first pump is an axially driven uni-ventricular assist pump, in which the rotor with impeller is radially supported by two passive magnetic bearings, but has one point contact with the stator axially at standstill. As the pump raises its rotating speed, the increasing hydrodynamic force of fluid acting on the impeller will make the rotor taking off from contacting point and disaffiliate from the stator. Then the rotor becomes fully suspended. The second pump is a radially driven bi-ventricular assist pump, i.e., an impeller total artificial heart. Its rotor with two impellers on both ends is supported by two passive magnetic bearings, which counteract the attractive force between rotor magnets and stator coil iron core. The rotor is affiliated to the stator radially at standstill and becomes levitated during rotation. Therefore, the rotor keeps concentric with stator during rotation but eccentric at standstill, as is confirmed by rotor position detection with Honeywell sensors. It concludes that the permanent maglev needs action of a non-magnetic force to achieve stability but a rotating magnetic levitator with high speed and large inertia can maintain its stability merely with passive magnetic bearings.

Model Studies of the Dynamics of Bacterial Flagellar Motors

Science.gov (United States)

Bai, Fan; Lo, Chien-Jung; Berry, Richard M.; Xing, Jianhua

2009-01-01

Abstract The bacterial flagellar motor is a rotary molecular machine that rotates the helical filaments that propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation, and switching mechanism of the motor. In a previous article, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here, we further analyze that model, showing that 1), the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with latest experiments; 2), with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, as recently observed; and 3), the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwell-time distribution. The predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental procedures for verification. PMID:19383460

Dynamic model of cage induction motor with number of rotor bars as parameter

Directory of Open Access Journals (Sweden)

Gojko Joksimović

2017-05-01

Full Text Available A dynamic mathematical model, using number of rotor bars as parameter, is reached for cage induction motors through the use of coupled-circuits and the concept of winding functions. The exact MMFs waveforms are accounted for by the model which is derived in natural frames of reference. By knowing the initial motor parameters for a priori adopted number of stator slots and rotor bars model allows change of rotor bars number what results in new model parameters. During this process, the rated machine power, number of stator slots and stator winding scheme remain the same. Although presented model has a potentially broad application area it is primarily suitable for the analysis of the different stator/rotor slot combination on motor behaviour during the transients or in steady-state regime. The model is significant in its potential to provide analysis of dozen of different number of rotor bars in a few tens of minutes. Numerical example on cage rotor induction motor exemplifies this application, including three variants of number of rotor bars.

Model Studies of the Dynamics of Bacterial Flagellar Motors

Energy Technology Data Exchange (ETDEWEB)

Bai, F; Lo, C; Berry, R; Xing, J

2009-03-19

The Bacterial Flagellar Motor is a rotary molecular machine that rotates the helical filaments which propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation and switching mechanism of the motor. In our previous paper, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here we further analyze this model. In this paper we show (1) the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with the latest experiment by Lo et al.; (2) with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, recently observed by Yuan and Berg; (3) the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwelling time distribution. Predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental verification.

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

Science.gov (United States)

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.

X-ray generator

Energy Technology Data Exchange (ETDEWEB)

Zucarias, A; Shepherd, J W

1982-09-08

An X-ray tube has a tubular envelope with a cathode for directing an electron beam onto a focal spot area of a spaced anode target to generate X-rays. The target is mounted for axial rotation on one end of a rotor disposed in an end portion of the envelope and encircled by a stator of an alternating current induction motor. An annular shield of high permeability magnetic material extends transversely between the electron beam and the stator of the induction motor for shunting stray or fringe electromagnetic fields established by the stator away from the electron beam to avoid consequent lateral deflections of the electron and corresponding lateral movements of the focal spot area.

Efficient Propulsion Structure with an Axial Flux Rotary Converter for HEV Drive Unit

Directory of Open Access Journals (Sweden)

Ales Havel

2011-01-01

Full Text Available This paper describes an efficient axial flux arrangement of the four quadrant rotary converter for hybrid electric vehicles. The design of the axial flux wound stator and both axial flux squirrel cage rotors is based on the arrangement of radial air gap induction motor and permanent magnet synchronous motor. The method of constant magnetic circuit volume is utilized for dimensions conversion, which results into basic dimensions of stator and rotor discs in axial flux conception. This allows the creation of real 3D models in the CAD application. Finally, the finite element simulations of electromagnetic induction in the axial flux stator pack are presented in the concluding part of this paper.

Micro grid control strategy of DFIG unit based on improved DC grid connected topology

Science.gov (United States)

Zongze, Xia; Fei, Xia; Zhixiong, Yang

2017-05-01

Aiming to the application of the DFIG connected to DC-Microgrids, an improved topology for the DFIG connected to DC-Microgrids is taken into account in this thesis. The stator side loses the support of voltage and frequency of AC point of common coupling bus. A novel control method suitable to the stator side converter (SSC) and the rotor side converter (RSC) of the topology is proposed. The independent control of stator voltage and frequency, the decoupled control of power and variable speed constant frequency of DFIG are achieved in the doubly-fed induction generator connected to DC-Microgrids. which can enhance the capacity of active power transmission of DFIG during the voltage variation.

Elimination of torque pulsations in a direct drive EV wheel motor

Energy Technology Data Exchange (ETDEWEB)

Hredzak, B.; Gair, S. [Napier Univ., Edinburgh (United Kingdom); Eastham, J.F. [Univ. of Bath (United Kingdom)

1996-09-01

Double sided axial field machines are attractive for direct wheel drives in electric vehicles. This is due to the fact that stator/rotor misalignments can be accommodated. In this case the stator of the machine is envisaged mounted on the chassis of the car while the rotor directly drives the road wheel. Since the wheel is perturbed by the road surface the rotor will move vertically between the outside stator assemblies and thus give rise to torque pulsations. A vector control scheme has been implemented whereby the torque pulsations are eliminated by (i) calculation of the flux variation due to the rotor perturbation and (ii) using this signal for the modulation of the motor input current.

A Field Theory Approach to Modeling Helical FCG's

International Nuclear Information System (INIS)

Fortgang, C.M.

1998-01-01

Often helical flux-compressor generator (FCG) design codes are essentially circuit codes which utilize known equations for parameterizing circuit elements such as armature and stator inductance. The authors present an analytical model that is based more on first principals. The stator inductance is calculated using a definition of inductance in terms of the magnetic vector-potential. The calculation accounts for winding-pitch, bifurcations, and works for any ratio of length to diameter. The currents on the armature are calculated self-consistently and are not assumed to simply 'mirror' the stator currents. Resistive losses and magnetic diffusion losses are calculated less rigorously but they are working on better methods. Details of the model and comparison with experiment will be presented

Doubly fed induction generator based wind turbine systems subject to recurring grid faults

DEFF Research Database (Denmark)

Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan

2014-01-01

New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the Doubly Fed Induction Generator wind turbine system under recurring grid faults is analyzed. The stator natural flux produced by the voltage recovery after the first grid fault...... may be superposed on the stator natural flux produced by the second grid fault, and it may result in large current and voltage transient. The damping of the stator natural flux can be accelerated with a rotor natural current in its opposite direction after voltage recovery, but larger torque....... The performance of DFIG under recurring grid faults is verified by the simulation and experiments....

A robust predictive current controller for healthy and open-circuit faulty conditions of five-phase BLDC drives applicable for wind generators and electric vehicles

International Nuclear Information System (INIS)

Salehi Arashloo, Ramin; Salehifar, Mehdi; Romeral, Luis; Sala, Vicent

2015-01-01

Highlights: • Model predictive deadbeat control of generator stator phase currents. • Fault tolerant control of five-phase BLDC generator. • Control of stator phase currents under normal and open-circuit faulty conditions. • MATLAB simulation and experimental verification of proposed control method. • Verification of robustness and fast respond of proposed controlling method. - Abstract: Fault tolerant control of five-phase brushless direct current (BLDC) machines is gaining more importance in high-safety applications such as offshore wind generators and automotive industries. In many applications, traditional controllers (such as PI controllers) are used to control the stator currents under faulty conditions. These controllers have good performance with dc signals. However, in the case of missing one or two of the phases, appropriate reference currents of these machines have oscillatory dynamics both in phase- and synchronous-reference frames. Non-constant nature of these reference values requires the implication of fast current controllers. In this paper, model predictive deadbeat controllers are proposed to control the stator currents of five-phase BLDC machines under normal and faulty conditions. Open circuit fault is considered for both one and two stator phases, and the behaviour of proposed controlling method is evaluated. This evaluation is generally focused on first, sensitivity of proposed controlling method and second, its speed in following reference current values under transient states. Proposed method is simulated and is verified experimentally on a five-phase BLDC drive

On the Use of Surface Porosity to Reduce Unsteady Lift

Science.gov (United States)

Tinetti, Ana F.; Kelly, Jeffrey J.; Bauer, Steven X. S.; Thomas, Russell H.

2001-01-01

An innovative application of existing technology is proposed for attenuating the effects of transient phenomena, such as rotor-stator and rotor-strut interactions, linked to noise and fatigue failure in turbomachinery environments. A computational study was designed to assess the potential of passive porosity technology as a mechanism for alleviating interaction effects by reducing the unsteady lift developed on a stator airfoil subject to wake impingement. The study involved a typical high bypass fan Stator airfoil (solid baseline and several porous configurations), immersed in a free field and exposed to the effects of a transversely moving wake. It was found that, for the airfoil under consideration, the magnitude of the unsteady lift could be reduced more than 18% without incurring significant performance losses.

Electromagnetic device of the safety screw-nut type

International Nuclear Information System (INIS)

Defaucheux, Jean; Guedj, Freddy.

1981-01-01

System providing for the vertical displacement of nuclear reactor control rods in a non-magnetic and cylindrical leak tight containment. This device is composed of a stator located around the upper part of the containment and, inside this containment, a rotor also in the upper part of this containment, which is free in axial translation along its shaft which it drives rotationally but which is fixed in translation. This shaft drives a threaded rod working in conjunction with a nut and able to slide vertically without turning inside the containment and supporting the reactor control rods. When the stator is not powered, the threaded rod and nut assembly falls to the bottom of the containment and may be easily raised by powering the stator [fr

Fixture for aligning motor assembly

Science.gov (United States)

Shervington, Roger M.; Vaghani, Vallabh V.; Vanek, Laurence D.; Christensen, Scott A.

2009-12-08

An alignment fixture includes a rotor fixture, a stator fixture and a sensor system which measures a rotational displacement therebetween. The fixture precisely measures rotation of a generator stator assembly away from a NULL position referenced by a unique reference spline on the rotor shaft. By providing an adjustable location of the stator assembly within the housing, the magnetic axes within each generator shall be aligned to a predetermined and controlled tolerance between the generator interface mounting pin and the reference spline on the rotor shaft. Once magnetically aligned, each generator is essentially a line replaceable unit which may be readily mounted to any input of a multi-generator gearbox assembly with the assurance that the magnetic alignment will be within a predetermined tolerance.

Special-Purpose High-Torque Permanent-Magnet Motors

Science.gov (United States)

Doane, George B., III

1995-01-01

Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

Three-degree-of-freedom ultrasonic motor using a 5-mm-diameter piezoelectric ceramic tube.

Science.gov (United States)

Mingsen Guo; Junhui Hu; Hua Zhu; Chunsheng Zhao; Shuxiang Dong

2013-07-01

A small three-degree-of-freedom ultrasonic motor has been developed using a simple piezoelectric lead zirconate titanate (PZT)-tube stator (OD 5 mm, ID 3 mm, length 15 mm). The stator drives a ball-rotor into rotational motion around one of three orthogonal (x-, y-, and z-) axes by combing the first longitudinal and second bending vibration modes. A motor prototype was fabricated and characterized; its performance was superior to those of previous motors made with a PZT ceramic/metal composite stator of comparable size. The method for further improving the performance was discussed. The motor can be further miniaturized and it has potential to be applied to medical microrobots, endoscopes or micro laparoscopic devices, and cell manipulation devices.

Investigation of the influence of air gap thickness and eccentricity on the noise of the rotating electrical machine

Directory of Open Access Journals (Sweden)

Donát M.

2013-12-01

Full Text Available This article deals with the numerical modelling of the dynamic response of the rotating electrical machine on the application of the magnetic forces. The special attention is paid to the modelling of the magnetic forces that act on the stator winding of the machine and the computational model of the modal properties of the stator winding. The created computational model was used to investigation of the influence of the nominal air gap thickness and the air gap eccentricity on the sound power radiated by outer surface of the stator of the machine. The obtained results show that the nominal air gap thickness has slightly greater influence on the sound power of the machine than eccentricity of the air gap.

Wind turbine generators having wind assisted cooling systems and cooling methods

Science.gov (United States)

Bagepalli, Bharat [Niskayuna, NY; Barnes, Gary R [Delanson, NY; Gadre, Aniruddha D [Rexford, NY; Jansen, Patrick L [Scotia, NY; Bouchard, Jr., Charles G.; Jarczynski, Emil D [Scotia, NY; Garg, Jivtesh [Cambridge, MA

2008-09-23

A wind generator includes: a nacelle; a hub carried by the nacelle and including at least a pair of wind turbine blades; and an electricity producing generator including a stator and a rotor carried by the nacelle. The rotor is connected to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity. A cooling system is carried by the nacelle and includes at least one ambient air inlet port opening through a surface of the nacelle downstream of the hub and blades, and a duct for flowing air from the inlet port in a generally upstream direction toward the hub and in cooling relation to the stator.

Reluctance device

International Nuclear Information System (INIS)

Claridge, A.N.; Smith, A.J.

1983-01-01

A reluctance device comprises two or more phases, each of which has a rotor mounted for rotation within a tubular member and an annular stator positioned externally of the tubular member. The rotor and the internal surface of the tubular member are each provided with aligned, axially spaced apart annular arrays of teeth, the teeth on the rotor confronting those on the tubular member in radially spaced apart relationship. The stator encloses a coil which, when electrically energised, creates a plurality of magnetic flux paths each of which extends radially between the rotor and stator via the confronting teeth and the tubular member, and axially along both the rotor and the portion of the stator located radially outwardly of the coil. The portion of the tubular member intermediate the teeth thereon is provided with a non-magnetic insert in order to resist the axial passage of magnetic flux therethrough. In one of the claims, the tubular member comprises a portion of a nuclear reactor which is adapted to contain a reactor control rod, the rotor constituting a portion of the drive mechanism for the control rod contained in operation within the tubular member. (author)

Simulation of Casing Treatments of a Transonic Compressor Stage

Directory of Open Access Journals (Sweden)

M. Hembera

2008-01-01

Full Text Available This article presents the study of casing treatments on an axial compressor stage for improving stability and enhancing stall margin. So far, many simulations of casing treatments on single rotor or rotor-stator configurations were performed. But as the application of casing treatments in engines will be in a multistage compressor, in this study, the axial slots are applied to a typical transonic first stage of a high-pressure 4.5-stage compressor including an upstream IGV, rotor, and stator. The unsteady simulations are performed with a three-dimensional time accurate Favre-averaged Navier-stokes flow solver. In order to resolve all important flow mechanisms appearing through the use of casing treatments, a computational multiblock grid consisting of approximately 2.4 million nodes was used for the simulations. The configurations include axial slots in 4 different variations with an axial extension ranging into the blade passage of the IGV. Their shape is semicircular with no inclination in circumferential direction. The simulations proved the effectiveness of casing treatments with an upstream stator. However, the results also showed that the slots have to be carefully positioned relative to the stator location.

Comparative FEM-based Analysis of Multiphase Induction Motor

Directory of Open Access Journals (Sweden)

Leonard Livadaru

2014-09-01

Full Text Available This paper presents a comparative study of multiphase induction motor, which has alternately three-, five- and six-phase stator winding. The machine has been designed particularly for this purpose and has individual ring coils placed in each stator slot. The study consists in FEM analyses and mainly looks for the particularities of magnetic quantities such as air-gap flux density and electromagnetic torque.

Equipment improvements for performance enhancement

International Nuclear Information System (INIS)

Gaestel, P.; Guesnon, H.; Sauze, G.

1994-01-01

In order to enhance the reactor availability, several improvements on reactor equipment have been developed: design optimization for stator maintenance replacement in the main alternator; adjustment modification of stator coils in the main alternator for an easier maintenance; improvement of the fuel handling line (pole crane, transfer equipment, loading machine); development of a loose part trapping system in the steam generator secondary circuit. 1 tab

Source of seismic signals

Energy Technology Data Exchange (ETDEWEB)

Frankovskii, B.A.; Khor' yakov, K.A.

1980-08-30

Patented is a source of seismic signals consisting of a shock generator with a basic low-voltage and auxillary high-voltage stator coils, a capacitive transformer and control switches. To increase the amplitude of signal excitation a condensor battery and auxillary commutator are introduced into the device, which are connected in parallel and serially into the circuit of the main low-voltage stator coil.

Removable bearing arrangement for a wind turbine generator

Science.gov (United States)

Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

2010-06-15

A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

the impact of machine geometries on the average torque of dual ...

African Journals Online (AJOL)

HOD

Keywords: average torque, dual start, machine geometry, optimal value, PM machines. 1. ... permanent magnet length, back-iron size etc. were ..... e (N m. ) Stator tooth width/stator slot pitch. 4. 5. 7. 8. 10. 11. 13. 14. Number of rotor poles. 0. 1. 2. 3. 4. 5. 6. 0. 2. 4. 6. 8. 10. 12. T orq u e (Nm. ) Back-iron thickness (mm). 4. 5. 7.

Analysis of the NASA White Sands Test Facility (WSTF) Test System for Friction-Ignition of Metallic Materials

Science.gov (United States)

Shoffstall, Michael S.; Wilson, D. Bruce; Stoltzfus, Joel M.

2000-01-01

Friction is a known ignition source for metals in oxygen-enriched atmospheres. The test system developed by the NASA White Sands Test Facility in response to ASTM G-94 has been used successfully to determine the relative ignition from friction of numerous metallic materials and metallic materials pairs. These results have been ranked in terms of a pressure-velocity product (PV) as measured under the prescribed test conditions. A high value of 4.1(exp 8) watts per square meter for Inconel MA 754 is used to imply resistance to friction ignition, whereas a low value of 1.04(exp 8) watts per square meter for stainless steel 304 is taken as indicating material susceptible to friction ignition. No attempt has been made to relate PV values to other material properties. This work reports the analysis of the WSTF friction-ignition test system for producing fundamental properties of metallic materials relating to ignition through friction. Three materials, aluminum, titanium, and nickel were tested in the WSTF frictional ignition instrument system under atmospheres of oxygen or nitrogen. Test conditions were modified to reach a steady state of operation, that is applied, the force was reduced and the rotational speed was reduced. Additional temperature measurements were made on the stator sample. The aluminum immediately galled on contact (reproducible) and the test was stopped. Titanium immediately ignited as a result of non-uniform contact of the stator and rotor. This was reproducible. A portion of the stator sampled burned, but the test continued. Temperature measurements on the stator were used to validate the mathematical model used for estimating the interface (stator/rotor) temperature. These interface temperature measurements and the associate thermal flux into the stator were used to distinguish material-phase transitions, chemical reaction, and mechanical work. The mechanical work was used to analyze surface asperities in the materials and to estimate a

Improved Electromagnetic Brake

Science.gov (United States)

Martin, Toby B.

2004-01-01

A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may

Analysis and control of excitation, field weakening and stability in direct torque controlled electrically excited synchronous motor drives

Energy Technology Data Exchange (ETDEWEB)

Pyrhoenen, O

1999-12-31

Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor`s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque

Analysis and control of excitation, field weakening and stability in direct torque controlled electrically excited synchronous motor drives

Energy Technology Data Exchange (ETDEWEB)

Pyrhoenen, O.

1998-12-31

Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor`s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque

Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flights Conditions

Science.gov (United States)

Elliott, David M.; Woodward, Richard P.; Podboy, Gary G.

2010-01-01

Two novel fan noise reduction technologies, over the rotor acoustic treatment and soft stator vane technologies, were tested in an ultra-high bypass ratio turbofan model in the NASA Glenn Research Center s 9- by 15-Foot Low-Speed Wind Tunnel. The performance of these technologies was compared to that of the baseline fan configuration, which did not have these technologies. Sideline acoustic data and hot film flow data were acquired and are used to determine the effectiveness of the various treatments. The material used for the over the rotor treatment was foam metal and two different types were used. The soft stator vanes had several internal cavities tuned to target certain frequencies. In order to accommodate the cavities it was necessary to use a cut-on stator to demonstrate the soft vane concept.

Reactive power generation in high speed induction machines by continuously occurring space-transients

Science.gov (United States)

Laithwaite, E. R.; Kuznetsov, S. B.

1980-09-01

A new technique of continuously generating reactive power from the stator of a brushless induction machine is conceived and tested on a 10-kw linear machine and on 35 and 150 rotary cage motors. An auxiliary magnetic wave traveling at rotor speed is artificially created by the space-transient attributable to the asymmetrical stator winding. At least two distinct windings of different pole-pitch must be incorporated. This rotor wave drifts in and out of phase repeatedly with the stator MMF wave proper and the resulting modulation of the airgap flux is used to generate reactive VA apart from that required for magnetization or leakage flux. The VAR generation effect increases with machine size, and leading power factor operation of the entire machine is viable for large industrial motors and power system induction generators.

Clocking In Turbines: Remarks On Physical Nature And Geometric Requirements

Directory of Open Access Journals (Sweden)

Swirydczuk Jerzy

2015-04-01

Full Text Available The article discusses two issues relating to the clocking phenomenon in turbines, which are the physical course of stator wake deformation in rotor passages and its further interaction with downstream stator blades, and turbine geometry parameters which are believed to be most favourable for clocking. In both cases, the results presented in the article have made it possible to verify and reformulate the previously accepted opinions.

Development of Maglev and linear drive technology for transportation in Japan

Energy Technology Data Exchange (ETDEWEB)

Masada, Eisuke [Tokyo Univ. (Germany)

1996-12-31

In order to realise guided ground transportation systems with superspeed, better riding comforts and environmental effects two types of maglev transports, JR-Maglev and HSST have been developed since 20 years in Japan. JR-Maglev is bases on a electro-dynamic suspension system and driven by long-stator linear synchronous motors. HSST is an electromagnetic suspension system with short-stator linear induction motor. Both systems are presented. (HW)

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Flux estimation algorithms for electric drives: a comparative study

OpenAIRE

Koteich , Mohamad

2016-01-01

International audience; This paper reviews the stator flux estimation algorithms applied to the alternating current motor drives. The so-called voltage model estimation, which consists of integrating the back-electromotive force signal, is addressed. However, in practice , the pure integration is prone to drift problems due to noises, measurement error, stator resistance uncertainty and unknown initial conditions. This limitation becomes more restrictive at low speed operation. Several soluti...

Influence of the braking power control of the traction asynchronous machine in the voltage vector control system under DC

Directory of Open Access Journals (Sweden)

Юлія Олександрівна Слободенюк

2016-11-01

Full Text Available At braking the traction motors are transferred to generator mode and produce electrical energy which passes to the contact mains or storage device in the DC mains for further use. Such braking is called regenerative. The resulting electrical energy can be spent by trains in traction mode. Regenerative braking reduces the consumption of electric power for traction. In electric railways of our country more than 3% of the consumed electrical energy is given back to contact mains annually. As this takes place there arises the task to control the braking of the traction motors with minimal impact on electric power quality and maintaining proper braking performance. Based on the analysis of the characteristics of the brake traction of an electric locomotive with asynchronous electric machines the main braking modes have been chosen: at a constant sliding speed and the stator constant voltage; at constant braking power and the stator constant voltage; at a power value more than the nominal braking power; at a constant load torque; at a constant frequency of the stator. The vector control system with the formation of the reactive component of the stator current and the EMF regulator was chosen, basing on the working conditions characteristics in the electric braking mode (recuperation; namely, that the characteristics are defined by the laws regulating the frequency and voltage across the stator windings. This control system can fully reproduce any predetermined trajectory of traction and braking performance and adjust braking power. The offered system with recuperation can be used as a means of compensation in emergency situations with a power failure

Impact of fluorescent protein fusions on the bacterial flagellar motor.

Science.gov (United States)

Heo, M; Nord, A L; Chamousset, D; van Rijn, E; Beaumont, H J E; Pedaci, F

2017-10-03

Fluorescent fusion proteins open a direct and unique window onto protein function. However, they also introduce the risk of perturbation of the function of the native protein. Successful applications of fluorescent fusions therefore rely on a careful assessment and minimization of the side effects, but such insight is still lacking for many applications. This is particularly relevant in the study of the internal dynamics of motor proteins, where both the chemical and mechanical reaction coordinates can be affected. Fluorescent proteins fused to the stator of the Bacterial Flagellar Motor (BFM) have previously been used to unveil the motor subunit dynamics. Here we report the effects on single motors of three fluorescent proteins fused to the stators, all of which altered BFM behavior. The torque generated by individual stators was reduced while their stoichiometry remained unaffected. MotB fusions decreased the switching frequency and induced a novel bias-dependent asymmetry in the speed in the two directions. These effects could be mitigated by inserting a linker at the fusion point. These findings provide a quantitative account of the effects of fluorescent fusions to the stator on BFM dynamics and their alleviation- new insights that advance the use of fluorescent fusions to probe the dynamics of protein complexes.

Experience on tangent delta norms adopted for repaired generator

International Nuclear Information System (INIS)

Misra, N.N.; Sood, D.K.

2005-01-01

The repair techniques of the generators are very crucial for avoiding prolonged forced outages. The crucial decisions based on sound knowledge and judgement becomes essential in many cases. The unit under discussions had failed on account of flash over in the Exciter end overhang windings. The failure resulted in damaged to the stator bars as well as generator core. The damaged end packets of the stator core were replaced at site. The total winding bars were removed from stator core and damaged bars were replaced with new bars. The rest of the bars were tested for tangent delta tests for reuse. Acceptance norms of 0.6% tip up from 0.2pu to 0.6pu of rated stator voltage were adopted. Some of the bars outside the acceptable limits of tangent delta were shifted close to neutral so that the standard norms of tan delta are met. This was felt necessary because lead-time for procurement of new bars was more than six months. The above-adopted norms for tangent delta will be of much use for the operating utilities. The unit under discussions was of 67.5 MW operating at 50 Hz, 0.85 pf lag and had logged 66160.46 operating hours before failure. (author)

Analysis of mechanical behavior and hysteresis heat generating mechanism of PDM motor

Energy Technology Data Exchange (ETDEWEB)

Shi, Changshuai; Zhu, Xiaohua; Tang, Liping [Southwest Petroleum University, Chengdu (China); Deng, Juan [Avic Chengdu Engine (Group) Co.,Ltd, Chengdu (China)

2017-03-15

Positive displacement motor (PDM), which is prone to high temperature fatigue failure, can be weakened in its application in deep and superdeep well. In order to study the forced state, deformation regularity and thermal hysteresis of PDM motor, the paper established the three-dimensional thermal-mechanical coupled Finite element model (FEM). Based on the theoretical research, experimental study and numerical simulation, the study found that the displacement of stator lining shows a sinusoidal variation under internal pressure, when adapting the general form of sine function to fitting inner contour line deformation function. Then the paper analyzed the hysteresis heat generating mechanism of the motor, learning that hysteresis thermogenous of stator lining occurs due to the viscoelastic of rubber material and cyclic loading of stator lining. A heartburn happens gradually in the center of the thickest part of the stator lining as temperature increases, which means work efficiency and service life of PDM will be decreased when used in deep or superdeep well. In this paper, we established a theory equation for the choice of interference fit and motor line type optimization design, showing hysteresis heat generating analyzing model and method are reasonable enough to significantly improve PDM’s structure and help better use PDM in deep and surdeep well.

Optimal Design of an Axial-Flux Permanent-Magnet Middle Motor Integrated in a Cycloidal Reducer for a Pedal Electric Cycle

Directory of Open Access Journals (Sweden)

Yee-Pien Yang

2015-12-01

Full Text Available This paper proposes an optimal design of a middle motor integrated into a mid-drive unit for pedal electric cycles. This middle motor is an axial-flux permanent magnet brushless DC motor with a stator plate. Facing this plate is a rotor plate that acts as an eccentric component of a cycloidal reducer next to the stator. Both the middle motor and cycloidal reducer are easily installed on the same axle of the bike crankset. In the preliminary design, driving requirements are used to make the middle motor specifications. The numbers of stator slots and magnet poles on the rotor were chosen to achieve the best winding factor, and the winding layout was determined accordingly. A one-dimensional magnetic circuit model of the middle motor was built, and its shape was optimized utilizing a multifunctional optimization system tool. Finally, the resulting design was verified and refined by a finite element analysis. A prototype of the middle motor was fabricated with a stator made of a soft magnetic composite and integrated with a cycloidal reducer. Experimental results show that the motor has a sinusoidal back electromotive force. Additionally, it is easily controlled by sinusoidal currents with acceptable torque and speed curves.

Analysis of mechanical behavior and hysteresis heat generating mechanism of PDM motor

International Nuclear Information System (INIS)

Shi, Changshuai; Zhu, Xiaohua; Tang, Liping; Deng, Juan

2017-01-01

Positive displacement motor (PDM), which is prone to high temperature fatigue failure, can be weakened in its application in deep and superdeep well. In order to study the forced state, deformation regularity and thermal hysteresis of PDM motor, the paper established the three-dimensional thermal-mechanical coupled Finite element model (FEM). Based on the theoretical research, experimental study and numerical simulation, the study found that the displacement of stator lining shows a sinusoidal variation under internal pressure, when adapting the general form of sine function to fitting inner contour line deformation function. Then the paper analyzed the hysteresis heat generating mechanism of the motor, learning that hysteresis thermogenous of stator lining occurs due to the viscoelastic of rubber material and cyclic loading of stator lining. A heartburn happens gradually in the center of the thickest part of the stator lining as temperature increases, which means work efficiency and service life of PDM will be decreased when used in deep or superdeep well. In this paper, we established a theory equation for the choice of interference fit and motor line type optimization design, showing hysteresis heat generating analyzing model and method are reasonable enough to significantly improve PDM’s structure and help better use PDM in deep and surdeep well

A Robust Sensorless Direct Torque Control of Induction Motor Based on MRAS and Extended Kalman Filter

Directory of Open Access Journals (Sweden)

Mustapha MESSAOUDI

2008-06-01

Full Text Available In this paper, the classical Direct Torque Control (DTC of Induction Motor (IM using an open loop pure integration suffers from the well-known problems of integration especially in the low speed operation range is detailed. To tackle this problem, the IM variables and parameters estimation is performed using a recursive non-linear observer known as EKF. This observer is used to estimate the stator currents, the rotor flux linkages, the rotor speed and the stator resistance. The main drawback of the EKF in this case is that the load dynamics has to be known which is not usually possible. Therefore, a new method based on the Model Reference Adaptive System (MRAS is used to estimate the rotor speed. The two different nonlinear observers applied to sensorless DTC of IM, are discussed and compared to each other. The rotor speed estimation in DTC technique is affected by parameter variations especially the stator resistance due to temperature particularly at low speeds. Therefore, it is necessary to compensate this parameter variation in sensorless induction motor drives using an online adaptation of the control algorithm by the estimated stator resistance. A simulation work leads to the selected results to support the study findings.

Rotor-stator spinning disc reactor

NARCIS (Netherlands)

Meeuwse, M.

2011-01-01

The chemical industry is continuously working to make the production more efficient and safer. Process intensification is the trend in which new equipment and processing methods are developed, which require less energy, are safer and produce less waste products. The main improvements can be made by

Rotatable seal assembly

International Nuclear Information System (INIS)

Garibaldi, J.L.; Logan, C.M.

1982-01-01

An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an oring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers

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

Directory of Open Access Journals (Sweden)

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.

Film riding seals for rotary machines

Science.gov (United States)

Bidkar, Rahul Anil; Sarawate, Neelesh Nandkumar; Wolfe, Christopher Edward; Ruggiero, Eric John; Raj Mohan, Vivek Raja

2017-03-07

A seal assembly for a rotary machine is provided. The seal assembly includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the segments includes a shoe plate with a forward-shoe section and an aft-shoe section having one or more labyrinth teeth therebetween facing the rotor. The sealing device includes a stator interface element having a groove or slot for allowing disposal of a spline seal for preventing segment leakages. The sealing device segment also includes multiple bellow springs or flexures connected to the shoe plate and to the stator interface element. Further, the sealing device segments include a secondary seal integrated with the stator interface element at one end and positioned about the multiple bellow springs or flexures and the shoe plate at the other end.

Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

Energy Technology Data Exchange (ETDEWEB)

Monteiro, Jose Roberto Boffino de Almeida

1997-07-01

The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

EXPERIMENTATION OF THREE PHASE OUTER ROTATING SWITCHED RELUCTANCE MOTOR WITH SOFT MAGNETIC COMPOSITE MATERIALS

Directory of Open Access Journals (Sweden)

N. C. LENIN

2017-01-01

Full Text Available This paper presents the application of Soft Magnetic Composite (SMC material in Outer Rotating Switched Reluctance Motor (ORSRM. The presented stator core of the Switched Reluctance Motor was made of two types of material, the classical laminated silicon steel sheet and the soft magnetic composite material. First, the stator core made of laminated steel has been analysed. The next step is to analyse the identical geometry SRM with the soft magnetic composite material, SOMALOY for its stator core. The comparisons of both cores include the calculated torque and torque ripple, magnetic conditions, simplicity of fabrication and cost. The finite element method has been used to analyse the magnetic conditions and the calculated torque. Finally, tested results shows that SMC is a better choice for SRM in terms of torque ripple and power density.

Design Analysis of Taper Width Variations in Magnetless Linear Machine for Traction Applications

Directory of Open Access Journals (Sweden)

Saadha Aminath

2018-01-01

Full Text Available Linear motors are being used in a different application with a huge popularity in the use of transport industry. With the invention of maglev trains and other high-speed trains, linear motors are being used for the translation and braking applications for these systems. However, a huge drawback of the linear motor design is the cogging force, low thrust values, and voltage ripples. This paper aims to study the force analysis with change in taper/teeth width of the motor stator and mover to understand the best teeth ratio to obtain a high flux density and a high thrust. The analysis is conducted through JMAG software and it is found that the optimum teeth ratio for both the stator and mover gives an increase of 94.4% increases compared to the 0.5mm stator and mover width.

Influence of parameters detuning on induction motor NFO shaft-sensorless scheme

Directory of Open Access Journals (Sweden)

KULIC, F.

2010-11-01

Full Text Available In this paper, the parameter sensitivity analysis of shaft-sensorless induction motor drive with natural field orientation (NFO scheme is performed. NFO scheme calculates rotor flux position using the rotor flux vector reference only, does not require significant processor power and therefore it is suitable for low cost shaft sensorless drives. This concept also eliminates the need for sensitive stator voltage vector integration and it is usable in low rotor speed range. However, low speeds are coupled with low stator voltage amplitudes, which inflate the NFO scheme sensitivity to an error in stator resistance parameter. Similar problems can also take place if mutual inductance parameter is detuned, but this time in whole speed range. This paper investigates the influence of each parameter error on the NFO control steady state characteristics and dynamic performance.

The Rocket Electric Field Sounding (REFS) Program: Prototype Design and Successful First Launch

Science.gov (United States)

1992-01-15

insulators surrounding the stators, and stator edges themselves, are fully covered by the rotor , so that any effects of charge on the insulators are...Jumper performed a separate analysis of the aerodynamics (primarily the " Magnus effect ") induced by the relative rotation of rocket body and shell. The...significant advantages over an aircraft in simplicity and calibration. A single cylindrical rotor covering most of the payload acts as the shutter for all

Update of super-speed ground transportation technology development status and performance capabilities. CIGGT report No. 89-16

Energy Technology Data Exchange (ETDEWEB)

Hayes, W F

1990-01-01

This report presents an update of the Phase II assessment of development status and performance capabilities for four candidate super-speed ground transportation system alternatives for the Las Vegas-Southern California corridor. The four alternatives considered are the TGV wheel-on-rail technology, the Transrapid TR- 07 long-stator Electromagnetic Maglev (EMS) technology, the Japan Railways MLU Electrodynamic Maglev (EDS) technology, and the HSST Corp. HSST-400 short-stator Electromagnetic Maglev technology.

Direct Fuel Injector Power Drive System Optimization

Science.gov (United States)

2014-04-01

solenoid coil to create magnetic field in the stator. Then, the stator pulls the pintle to open the injector nozzle . This pintle movement occurs when the...that typically deal with power strategies to the injector solenoid coil. Numerical simulation codes for diesel injection systems were developed by...Laboratory) for providing the JP-8 test fuel. REFERENCES 1. Digesu, P. and Laforgia D., “ Diesel electro- injector : A numerical simulation code”. Journal of

A Self-Propelled Wheel for Wheeled Vehicles.

Science.gov (United States)

1996-09-05

embodiments of both types, in 16 general the axial permanent magnet motors feature a stator disk, 17 or drum, with a central opening and electrical...6 In general, in radial permanent magnet motors , the stator is 7 annularly-shaped and is concentrically disposed around a 8 generally cylindrically...is to provide a motor 6 assembly which is more efficient than the presently available 7 axial permanent magnet motors and radial permanent magnet motors 8

Relay protection coordination with generator capability curve, excitation system limiters and power system relay protections settings

OpenAIRE

Buha Danilo; Buha Boško; Jačić Dušan; Gligorov Saša; Božilov Marko; Marinković Savo; Milosavljević Srđan

2016-01-01

The relay protection settings performed in the largest thermal powerplant (TE "Nikola Tesla B") are reffered and explained in this paper. The first calculation step is related to the coordination of the maximum stator current limiter settings, the overcurrent protection with inverse characteristics settings and the permitted overload of the generator stator B1. In the second calculation step the settings of impedance generator protection are determined, and the methods and criteria according ...

INTENSITY SETTER FOR A DEVICE OF SMOOTH START OF SUBMERSIBLE PUMP ELECTRIC MOTOR

Directory of Open Access Journals (Sweden)

V.I. Lobov

2016-06-01

Full Text Available Purpose. Development of an intensity setter, which in a rational law changes the opening thyristor the voltage regulator and effectively to changing power supply voltage stator windings of the electric pump deepening, ensuring a smooth start in a wide range. Methodology. Electric submersible pump belongs to the small inertia electric, since it is not significant total moment of inertia, not exceeding two moments of inertia of the motor and static moment on the shaft does not exceed forty percent of the nominal torque. For technical requirements that electric acceleration time should have no less than twenty seconds or more. Office starting modes of electric submersible pumps economically justified using thyristor voltage regulator by forming the dial changes the intensity of the necessary legislation in time voltage feeding the stator windings. This ensures a smooth start right rotor of the electric submersible pump. Results. A block diagram of the intensity setter that is: with control unit, two units that form the exponential voltage supply emitter follower and regulatory elements. The mathematical expressions for voltage at the stator windings of the motor, changing exponentially, opening the angle of thyristor power unit thyristor the voltage regulator, which is determined through the initial angle of opening. Provided formula for pick-up voltage and minimum voltage, time constants, which are determined from the basic equations of motion and mechanical characteristics of the electric motor. Analytical investigated by the voltage dependence violation by changing the time constant flowing and growing exhibitor supply voltage stator electric circuit deepening pump. Originality. Proposed in the initial time on the stator windings of the electric pick-up voltage is applied. Under the influence of this voltage, motor rotor begins to accelerate. At the same time, pick-up voltage decreases the minimum startup voltage varies exponentially in which

System and method to determine electric motor efficiency using an equivalent circuit

Science.gov (United States)

Lu, Bin [Kenosha, WI; Habetler, Thomas G [Snellville, GA

2011-06-07

A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.

Core compressor exit stage study. Volume 3: Data and performance report for screening test configurations

Science.gov (United States)

Wisler, D. C.

1980-01-01

Rear stage blading designs that have lower losses in their endwall boundary layer regions were developed. Test data and performance results for rotor B, stator B, and stator C - blading designs that offer promise of reducing endwall losses relative to the baseline are given. A low speed research compressor was the principal investigative tool. The tests were conducted using four identical stages of blading so that the test data would be obtained in a true multistage environment.

Concepts for using trapped-flux bulk high-temperature superconductor in motors and generators

International Nuclear Information System (INIS)

Hull, John R; Strasik, Michael

2010-01-01

We review previous concepts for using bulk high-temperature superconductors (HTSs) in motors and generators and discuss methods for using trapped-flux (TF) HTSs in motors and generators that have been recently investigated in our laboratory. We examine the expected performance of a brushless motor/generator that uses TF bulk HTSs to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium for the stator and rotor cores.

Electric fluid pump

Science.gov (United States)

Van Dam, Jeremy Daniel; Turnquist, Norman Arnold; Raminosoa, Tsarafidy; Shah, Manoj Ramprasad; Shen, Xiaochun

2015-09-29

An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.

DESIGN EVALUATIONS OF DOUBLE ROTOR SWITCHED RELUCTANCE MACHINE

Directory of Open Access Journals (Sweden)

C.V. ARAVIND

2016-02-01

Full Text Available The absence of magnets makes the reluctance machine typical for low cogging operations with the torque depending on the stator rotor interaction area. The air gap between stator pole and rotor pole gives a huge effect on the reluctance variation. The primitive double rotor switched reluctance machine lags to improvise the effect of the ripple value though the torque density is higher compared to conventional machines. An optimised circular hole position and dimensioned in the stator pole of lowers the torque ripple and reduce the acoustic noise as presented in this paper. A comparative evaluation of the conventional double rotor machine with this improved structure is done through numerical design and evaluations for the same sizing. It is found that the motor constant square density. It is found that the double rotor switched reluctance machine is improved by 140% to conventional machine.

A novel proposal of cooperation between a cage induction generator and the three-phase grid

Directory of Open Access Journals (Sweden)

Szular Zbigniew

2016-01-01

Full Text Available In the paper, a new concept of the cooperation between a cage induction generator and the three-phase grid is presented. The induction generator is excited by a capacitor battery connected to the stator winding terminals. In order to ensure a stable operation, the battery capacity should be continuously adjusted. Three appropriate selected capacitors are connected to the stator winding terminals by means of two bi-directional controlled switches. The generator output voltage is stabilized by a suitable control of these switches. The stator winding terminals are also connected to the diode bridge rectifier. Energy in the DC bus is converted to the parameters of the three-phase grid (400 V, 50 Hz by means of a three-phase voltage source inverter. Examples of numerical calculation results of the proposed energy generation system are presented in the end part of the paper.

Permanent-magnet switched-flux machine

Science.gov (United States)

Trzynadlowski, Andrzej M.; Qin, Ling

2010-01-12

A permanent-magnet switched-flux (PMSF) device has a ferromagnetic outer stator mounted to a shaft about a central axis extending axially through the PMSF device. Pluralities of top and bottom stator poles are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the ferromagnetic outer stator. A ferromagnetic inner rotor is coupled to the shaft and has i) a rotor core having a core axis co-axial with the central axis; and ii) first and second discs having respective outer edges with first and second pluralities of permanent magnets (PMs) mounted in first and second circles, radially outwardly from the rotor core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

Permanent-magnet-less machine having an enclosed air gap

Science.gov (United States)

Hsu, John S [Oak Ridge, TN

2012-02-07

A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

A new digital ground-fault protection system for generator-transformer unit

Energy Technology Data Exchange (ETDEWEB)

Zielichowski, Mieczyslaw; Szlezak, Tomasz [Institute of Electrical Power Engineering, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50370 Wroclaw (Poland)

2007-08-15

Ground faults are one of most often reasons of damages in stator windings of large generators. Under certain conditions, as a result of ground-fault protection systems maloperation, ground faults convert into high-current faults, causing severe failures in power system. Numerous publications in renowned journals and magazines testify about ground-fault matter importance and problems reported by exploitators confirm opinions, that some issues concerning ground-fault protection of large generators have not been solved yet or have been solved insufficiently. In this paper a new conception of a digital ground-fault protection system for stator winding of large generator was proposed. The process of intermittent arc ground fault in stator winding has been briefly discussed and actual ground-fault voltage waveforms were presented. A new relaying algorithm, based on third harmonic voltage measurement was also drawn and the methods of its implementation and testing were described. (author)

Piezoelectric micromotor using a metal-ceramic composite structure.

Science.gov (United States)

Koc, B; Bouchilloux, P; Uchino, K

2000-01-01

This paper presents a new piezoelectric micromotor design, in which a uniformly electroded piezoelectric ring bonded to a metal ring is used as the stator. Four inward arms at the inner circumference of the metal ring transfer radial displacements into tangential displacements. The rotor ends in a truncated cone shape and touches the tips of the arms. A rotation takes place by exciting coupled modes of the stator element, such as a radial mode and a second bending mode of the arms. The behavior of the free stator was analyzed using the ATILA finite element software. Torque vs. speed relationship was measured from the transient speed change with a motor load. A starting torque of 17 microNm was obtained at 20 Vrms. The main features of this motor are low cost and easy assembly because of a simple structure and small number of components.

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

Science.gov (United States)

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.

Doubly Fed Induction Generator Wind Turbine Systems Subject to Recurring Symmetrical Grid Faults

DEFF Research Database (Denmark)

Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan

2016-01-01

New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the doubly Ffed induction generator (DFIG) wind turbine system under recurring symmetrical grid faults is analyzed. The mathematical model of the DFIG under recurring symmetrical...... grid faults is established. The analysis is based on the DFIG wind turbine system with the typical low-voltage ride-through strategy-with rotor-side crowbar. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced...... by the second grid fault, so that the transient rotor and stator current and torque fluctuations under the second grid fault may be influenced by the characteristic of the first grid fault, including the voltage dips level and the grid fault angle, as well as the duration between two faults. The mathematical...

Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

Science.gov (United States)

Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

2017-12-01

The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

Loss of life of induction motors under various operating anomalies

International Nuclear Information System (INIS)

Chugh, Tarun; Varde, P.V.

2016-01-01

Reliability studies conducted to study the various failure modes of all induction motors shows that one of failure modes i.e. winding failure is quite prevalent and accounts for high percentage of failures of motors. Thus, there is a pivotal need to understand the theory of winding failure and know how it can be prognosticated based on the input parameters, current operating environment and maintenance history of a motor. This paper defines loss of motor life as the loss of stator winding insulation life due to thermal and environmental stresses. From the thermal point of view, the stator winding insulation is the weakest part of a squirrel cage induction motor, and equations are developed to estimate the insulation Iife and hence the motor life. In this regard, an integrated model consisting of an electrical model, thermal model and insulation ageing model is developed to evaluate the effect of various anomalies/stressors e.g. overvoltage and voltage unbalance on the life of a motor. This model is used to quantify the loss of life of a 2.3 kW, 415 V induction motor. The electrical model is developed by conducting Open Circuit and Blocked Rotor Test on the motor and thereby deriving its equivalent circuit. Using the model, the stator winding losses are calculated and given as an input to the thermal model to find the temperature rise in the stator winding. The steady state temperature of the stator winding is given as an input to the insulation aging model which predicts the loss of life. This work presents a simple technique for calculating thermal parameters based on motor testing rather than from motor design data. The insulation ageing model is developed based on Eyring Equation considering temperature and humidity as stressors. (author)

Numerical Investigation on the Effects of Self-Excited Tip Flow Unsteadiness and Blade Row Interactions on the Performance Predictions of Low Speed and Transonic Compressor Rotors

Science.gov (United States)

Lee, Daniel H.

The impact blade row interactions can have on the performance of compressor rotors has been well documented. It is also well known that rotor tip clearance flows can have a large effect on compressor performance and stall margin and recent research has shown that tip leakage flows can exhibit self-excited unsteadiness at near stall conditions. However, the impact of tip leakage flow on the performance and operating range of a compressor rotor, relative to other important flow features such as upstream stator wakes or downstream potential effects, has not been explored. To this end, a numerical investigation has been conducted to determine the effects of self-excited tip flow unsteadiness, upstream stator wakes, and downstream blade row interactions on the performance prediction of low speed and transonic compressor rotors. Calculations included a single blade-row rotor configuration as well as two multi-blade row configurations: one where the rotor was modeled with an upstream stator and a second where the rotor was modeled with a downstream stator. Steady-state and time accurate calculations were performed using a RANS solver and the results were compared with detailed experimental data obtained in the GE Low Speed Research Compressor and the Notre Dame Transonic Rig at several operating conditions including near stall. Differences in the performance predictions between the three configurations were then used to determine the effect of the upstream stator wakes and the downstream blade row interactions. Results obtained show that for both the low speed and transonic research compressors used in this investigation time-accurate RANS analysis is necessary to accurately predict the stalling character of the rotor. Additionally, for the first time it is demonstrated that capturing the unsteady tip flow can have a larger impact on rotor performance predictions than adjacent blade row interactions.

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

Directory of Open Access Journals (Sweden)

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.

Three Level Diode Clamped Inverter Fed Induction Motor with Dtc-Svm

OpenAIRE

V. Ranjith Kumar

2013-01-01

This project presents a three-level diode-clamped inverter feeding an asynchronous motor drive with direct torque control (DTC). The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a diode-clamped inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel c...

Switching algorithm for maglev train double-modular redundant positioning sensors.

Science.gov (United States)

He, Ning; Long, Zhiqiang; Xue, Song

2012-01-01

High-resolution positioning for maglev trains is implemented by detecting the tooth-slot structure of the long stator installed along the rail, but there are large joint gaps between long stator sections. When a positioning sensor is below a large joint gap, its positioning signal is invalidated, thus double-modular redundant positioning sensors are introduced into the system. This paper studies switching algorithms for these redundant positioning sensors. At first, adaptive prediction is applied to the sensor signals. The prediction errors are used to trigger sensor switching. In order to enhance the reliability of the switching algorithm, wavelet analysis is introduced to suppress measuring disturbances without weakening the signal characteristics reflecting the stator joint gap based on the correlation between the wavelet coefficients of adjacent scales. The time delay characteristics of the method are analyzed to guide the algorithm simplification. Finally, the effectiveness of the simplified switching algorithm is verified through experiments.

Influence of magnetic saturation effects on the fault detection of induction motors

Directory of Open Access Journals (Sweden)

Drozdowski Piotr

2014-09-01

Full Text Available In this paper, the influence of impact damage to the induction motors on the zero-sequence voltage and its spectrum is presented. The signals detecting the damages result from a detailed analysis of the formula describing this voltage component which is induced in the stator windings due to core magnetic saturation and the discrete displacement of windings. Its course is affected by the operation of both the stator and the rotor. Other fault detection methods, are known and widely applied by analysing the spectrum of stator currents. The presented method may be a complement to other methods because of the ease of measurements of the zero voltage for star connected motors. Additionally, for converter fed motors the zero sequence voltage eliminates higher time harmonics displaced by 120 degrees. The results of the method application are presented through measurements and explained by the use of a mathematical model of the slip-ring induction motor

Advanced Electrical Machines and Machine-Based Systems for Electric and Hybrid Vehicles

Directory of Open Access Journals (Sweden)

Ming Cheng

2015-09-01

Full Text Available The paper presents a number of advanced solutions on electric machines and machine-based systems for the powertrain of electric vehicles (EVs. Two types of systems are considered, namely the drive systems designated to the EV propulsion and the power split devices utilized in the popular series-parallel hybrid electric vehicle architecture. After reviewing the main requirements for the electric drive systems, the paper illustrates advanced electric machine topologies, including a stator permanent magnet (stator-PM motor, a hybrid-excitation motor, a flux memory motor and a redundant motor structure. Then, it illustrates advanced electric drive systems, such as the magnetic-geared in-wheel drive and the integrated starter generator (ISG. Finally, three machine-based implementations of the power split devices are expounded, built up around the dual-rotor PM machine, the dual-stator PM brushless machine and the magnetic-geared dual-rotor machine. As a conclusion, the development trends in the field of electric machines and machine-based systems for EVs are summarized.

On Stability of Open-Loop Operation without Rotor Information for Brushless DC Motors

Directory of Open Access Journals (Sweden)

Zhong Wu

2014-01-01

Full Text Available Open-loop operation mode is often used to control the Brushless DC Motors (BLDCMs without rotor position sensors when the back electromotive force (EMF is too weak due to the very low rotor velocity. The rotor position information is not necessary in this mode and the stator windings are supplied with voltages under a certain ratio of the amplitude to the frequency. However, the rotor synchronization will be destroyed once if the commutation instant is inappropriate. In order to improve the reliability of the open-loop operation mode, a dynamic equation is established to represent the synchronization error between the rotor and the stator. Thereafter, the stability of the open-loop control mode is analyzed by using Lyapunov indirect method. Theoretical analysis indicates that the open-loop control mode is asymptotically stable only when the commutation instant of the stator current lags behind the ideal one suitably. Finally, theoretical analysis is verified through the experimental results of a certain BLDCM.

Halbach array DC motor/generator

Science.gov (United States)

Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

1998-01-06

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

Progress in development of high capacity magnetic HTS bearings

International Nuclear Information System (INIS)

Kummeth, P.; Nick, W.; Neumueller, H.-W.

2005-01-01

HTS magnetic bearings are inherently stable without an active feedback system. They provide low frictional losses, no wear and allow operation at high rotational speed without lubrication. So they are very promising for use in motors, generators and turbines. We designed and constructed an HTS radial bearing for use with a 400 kW HTS motor. It consists of alternating axially magnetized permanent magnet rings on the rotor and a segmented YBCO stator. Stator cooling is performed by liquid nitrogen, the temperature of the stator can be adjusted by varying the pressure in the cryogenic vessel. At 68 K maximum radial forces of more than 3.7 kN were found. These results range within the highest radial bearing capacities reported worldwide. The encouraging results lead us to develop a large heavy load HTS radial bearing. Currently a high magnetic gradient HTS bearing for a 4 MVA synchronous HTS generator is under construction

Halbach array DC motor/generator

Science.gov (United States)

Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

1998-01-01

A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

Direct-phase-variable model of a synchronous reluctance motor including all slot and winding harmonics

International Nuclear Information System (INIS)

Obe, Emeka S.; Binder, A.

2011-01-01

A detailed model in direct-phase variables of a synchronous reluctance motor operating at mains voltage and frequency is presented. The model includes the stator and rotor slot openings, the actual winding layout and the reluctance rotor geometry. Hence, all mmf and permeance harmonics are taken into account. It is seen that non-negligible harmonics introduced by slots are present in the inductances computed by the winding function procedure. These harmonics are usually ignored in d-q models. The machine performance is simulated in the stator reference frame to depict the difference between this new direct-phase model including all harmonics and the conventional rotor reference frame d-q model. Saturation is included by using a polynomial fitting the variation of d-axis inductance with stator current obtained by finite-element software FEMAG DC (registered) . The detailed phase-variable model can yield torque pulsations comparable to those obtained from finite elements while the d-q model cannot.

A Novel Dual-Permanent-Magnet-Excited Machine with Flux Strengthening Effect for Low-Speed Large-Torque Applications

Directory of Open Access Journals (Sweden)

Yujun Shi

2018-01-01

Full Text Available This paper proposes a novel dual-permanent-magnet-excited (DPME machine. It employs two sets of permanent magnets (PMs. One is on the rotor, the other is on the stator with PM arrays. When compared with the existing DPME machines, not all of the PMs are located in the slots formed by the iron teeth. Specifically, the radially magnetized PMs in the arrays are located under the short iron teeth, while the tangentially magnetized PMs are located in the slots formed by the long stator iron teeth and the radially magnetized PMs. Each long stator iron tooth is sandwiched by two tangentially magnetized PMs with opposite directions, thus resulting in the flux strengthening effect. The simulation analysis indicates that the proposed machine can offer large back EMF with low THD and large torque density with low torque ripple when compared with Machine I from a literature. Meanwhile, by comparison, the proposed machine has great potential in improving the power factor and efficiency.

Operation and design selection of high temperature superconducting magnetic bearings

International Nuclear Information System (INIS)

Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

2004-01-01

Axial and radial high temperature superconducting (HTS) magnetic bearings are evaluated by their parameters. Journal bearings possess advantages over thrust bearings. High magnetic gradients in a multi-pole permanent magnet (PM) configuration, the surrounding melt textured YBCO stator and adequate designs are the key features for increasing the overall bearing stiffness. The gap distance between rotor and stator determines the specific forces and has a strong impact on the PM rotor design. We report on the designing, building and measuring of a 200 mm prototype 100 kg HTS bearing with an encapsulated and thermally insulated melt textured YBCO ring stator. The encapsulation requires a magnetically large-gap (4-5 mm) operation but reduces the cryogenic effort substantially. The bearing requires 3 l of LN 2 for cooling down, and about 0.2 l LN 2 h -1 under operation. This is a dramatic improvement of the efficiency and in the practical usage of HTS magnetic bearings

Non-linear control of a doubly fed induction machine; Commande non-lineaire d'une machine asynchrone a double alimentation

Energy Technology Data Exchange (ETDEWEB)

Vidal, P.E.

2004-12-15

This study deals with linear and non-linear control strategies applied to the rotation speed feedback of a doubly fed induction machine (DFIM), whose stator and rotor windings are connected to two Pulse Width Modulation voltage source inverters. We choose to distribute the active powers between the stator and the rotor following a certain proportionality ratio. This leads to guarantee, in steady state operation, a stator and rotor angular frequencies sharing. This distribution is initially assured by two shared angular frequencies controllers, and in a second time by the means of the Park transformation angles directly. Two models are established: the first express the currents, and the second is linked with the fluxes. The simulations results of the linear control (field oriented control), and non-linear control (sliding mode control), show a good independence between the main flux and the torque. An experimental validation is also presented. The results presented show the satisfactory DFIM flux control. Special attention is paid to the active power dispatching. (author)

PZT Thin Film Piezoelectric Traveling Wave Motor

Science.gov (United States)

Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

1995-01-01

With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

Switching Algorithm for Maglev Train Double-Modular Redundant Positioning Sensors

Directory of Open Access Journals (Sweden)

Song Xue

2012-08-01

Full Text Available High-resolution positioning for maglev trains is implemented by detecting the tooth-slot structure of the long stator installed along the rail, but there are large joint gaps between long stator sections. When a positioning sensor is below a large joint gap, its positioning signal is invalidated, thus double-modular redundant positioning sensors are introduced into the system. This paper studies switching algorithms for these redundant positioning sensors. At first, adaptive prediction is applied to the sensor signals. The prediction errors are used to trigger sensor switching. In order to enhance the reliability of the switching algorithm, wavelet analysis is introduced to suppress measuring disturbances without weakening the signal characteristics reflecting the stator joint gap based on the correlation between the wavelet coefficients of adjacent scales. The time delay characteristics of the method are analyzed to guide the algorithm simplification. Finally, the effectiveness of the simplified switching algorithm is verified through experiments.

Development and characterization of magnetic HTS bearings for a 400 kW synchronous HTS motor

International Nuclear Information System (INIS)

Kummeth, P; Ries, G; Nick, W; Neumueller, H-W

2004-01-01

Promising results of static and dynamic investigations on various journal type test bearings encouraged us to develop a scaled-up HTS bearing, able to carry the HTS rotor of a 400 kW superconducting motor. The stator, a YBCO hollow cylinder of 203 mm inner diameter and 250 mm length, is cooled by liquid nitrogen. Permanent magnet rings with a diameter of 200 mm were mounted on a shaft with alternating polarity. Characterization of the bearing capacity was performed with three different YBCO stators at temperatures between 66 and 86 K in a test set-up. A significant influence of the temperature was found. At a stator temperature of 72 K and a rotation frequency of 25 Hz (corresponding to nominal motor speed) a radial bearing force of 2700 N was measured for the shaft at centre position. Under rotation of the shaft the bearing capacity is reduced. At present our results range within the highest radial bearing capacities reported world-wide

A Novel Approach for Multi Class Fault Diagnosis in Induction Machine Based on Statistical Time Features and Random Forest Classifier

Science.gov (United States)

Sonje, M. Deepak; Kundu, P.; Chowdhury, A.

2017-08-01

Fault diagnosis and detection is the important area in health monitoring of electrical machines. This paper proposes the recently developed machine learning classifier for multi class fault diagnosis in induction machine. The classification is based on random forest (RF) algorithm. Initially, stator currents are acquired from the induction machine under various conditions. After preprocessing the currents, fourteen statistical time features are estimated for each phase of the current. These parameters are considered as inputs to the classifier. The main scope of the paper is to evaluate effectiveness of RF classifier for individual and mixed fault diagnosis in induction machine. The stator, rotor and mixed faults (stator and rotor faults) are classified using the proposed classifier. The obtained performance measures are compared with the multilayer perceptron neural network (MLPNN) classifier. The results show the much better performance measures and more accurate than MLPNN classifier. For demonstration of planned fault diagnosis algorithm, experimentally obtained results are considered to build the classifier more practical.

Wind turbine/generator set having a stator cooling system located between stator frame and active coils

Science.gov (United States)

Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

2012-11-13

A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

Performance of a Folded-Strip Toroidally Wound Induction Machine

DEFF Research Database (Denmark)

Jensen, Bogi Bech; Jack, Alan G.; Atkinson, Glynn J.

2011-01-01

This paper presents the measured experimental results from a four-pole toroidally wound induction machine, where the stator is constructed as a pre-wound foldable strip. It shows that if the machine is axially restricted in length, the toroidally wound induction machine can have substantially...... shorter stator end-windings than conventionally wound induction machines, and hence that a toroidally wound induction machine can have lower losses and a higher efficiency. The paper also presents the employed construction method, which emphasizes manufacturability, and highlights the advantages...

The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

Science.gov (United States)

Antonovičs, Uldis; Bražis, Viesturs; Greivulis, Jānis

2009-01-01

The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

Robot-operated quality control station based on the UTT method

Science.gov (United States)

Burghardt, Andrzej; Kurc, Krzysztof; Szybicki, Dariusz; Muszyńska, Magdalena; Nawrocki, Jacek

2017-03-01

This paper presents a robotic test stand for the ultrasonic transmission tomography (UTT) inspection of stator vane thickness. The article presents the method of the test stand design in Autodesk Robot Structural Analysis Professional 2013 software suite. The performance of the designed test stand solution was simulated in the RobotStudio software suite. The operating principle of the test stand measurement system is presented with a specific focus on the measurement strategy. The results of actual wall thickness measurements performed on stator vanes are presented.

Impact of cyclostationarity on fan broadband noise prediction

Science.gov (United States)

Wohlbrandt, A.; Kissner, C.; Guérin, S.

2018-04-01

One of the dominant noise sources of modern Ultra High Bypass Ratio (UHBR) engines is the interaction of the rotor wakes with the leading edges of the stator vanes in the fan stage. While the tonal components of this noise generation mechanism are fairly well understood by now, the broadband components are not. This calls to further the understanding of the broadband noise generation in the fan stage. This article introduces a new extension to the Random Particle Mesh (RPM) method, which accommodates in-depth studies of the impact of cyclostationary wake characteristics on the broadband noise in the fan stage. The RPM method is used to synthesize a turbulence field in the stator domain using a URANS simulation characterized by time-periodic turbulence and mean flow. The rotor-stator interaction noise is predicted by a two-dimensional CAA computation of the stator cascade. The impact of cyclostationarity is decomposed into various effects, which are separately investigated. This leads to the finding that the periodic turbulent kinetic energy (TKE) and periodic flow have only a negligible effect on the radiated sound power. The impact of the periodic integral length scale (TLS) is, however, substantial. The limits of a stationary representation of the TLS are demonstrated making this new extension to the RPM method indispensable when background and wake TKE are of comparable level. Good agreement of the predictions with measurements obtained from the 2015 AIAA Fan Broadband Noise Prediction Workshop are also shown.

Gyro-effect stabilizes unstable permanent maglev centrifugal pump.

Science.gov (United States)

Qian, Kun-Xi

2007-03-01

According to Earnshaw's Theorem (1839), the passive maglev cannot achieve stable equilibrium and thus an extra coil is needed to make the rotor electrically levitated in a heart pump. The author had developed a permanent maglev centrifugal pump utilizing only passive magnetic bearings, to keep the advantages but to avoid the disadvantages of the electric maglev pumps. The equilibrium stability was achieved by use of so-called "gyro-effect": a rotating body with certain high speed can maintain its rotation stably. This pump consisted of a rotor (driven magnets and an impeller), and a stator with motor coil and pump housing. Two passive magnetic bearings between rotor and stator were devised to counteract the attractive force between the motor coil iron core and the rotor driven magnets. Bench testing with saline demonstrated a levitated rotor under preconditions of higher than 3,250 rpm rotation and more than 1 l/min pumping flow. Rotor levitation was demonstrated by 4 Hall sensors on the stator, with evidence of reduced maximal eccentric distance from 0.15 mm to 0.07 mm. The maximal rotor vibration amplitude was 0.06 mm in a gap of 0.15 mm between rotor and stator. It concluded that Gyro-effect can help passive maglev bearings to achieve stabilization of permanent maglev pump; and that high flow rate indicates good hydraulic property of the pump, which helps also the stability of passive maglev pump.

The high voltage homopolar generator

Science.gov (United States)

Price, J. H.; Gully, J. H.; Driga, M. D.

1986-11-01

System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

Hybrid vehicle motor alignment

Science.gov (United States)

Levin, Michael Benjamin

2001-07-03

A rotor of an electric motor for a motor vehicle is aligned to an axis of rotation for a crankshaft of an internal combustion engine having an internal combustion engine and an electric motor. A locator is provided on the crankshaft, a piloting tool is located radially by the first locator to the crankshaft. A stator of the electric motor is aligned to a second locator provided on the piloting tool. The stator is secured to the engine block. The rotor is aligned to the crankshaft and secured thereto.

Advanced Noise Control Fan: A 20-Year Retrospective

Science.gov (United States)

Sutliff, Dan

2016-01-01

The ANCF test bed is used for evaluating fan noise reduction concepts, developing noise measurement technologies, and providing a database for Aero-acoustic code development. Rig Capabilities: 4 foot 16 bladed rotor @ 2500 rpm, Auxiliary air delivery system (3 lbm/sec @ 6/12 psi), Variable configuration (rotor pitch angle, stator count/position, duct length), synthetic acoustic noise generation (tone/broadband). Measurement Capabilities: 112 channels dynamic data system, Unique rotating rake mode measuremen, Farfield (variable radius), Duct wall microphones, Stator vane microphones, Two component CTA w/ traversing, ESP for static pressures.

Permanent-magnet-less synchronous reluctance system

Science.gov (United States)

Hsu, John S

2012-09-11

A permanent magnet-less synchronous system includes a stator that generates a magnetic revolving field when sourced by an alternating current. An uncluttered rotor is disposed within the magnetic revolving field and spaced apart from the stator to form an air gap relative to an axis of rotation. The rotor includes a plurality of rotor pole stacks having an inner periphery biased by single polarity of a north-pole field and a south-pole field, respectively. The outer periphery of each of the rotor pole stacks are biased by an alternating polarity.

Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces

Science.gov (United States)

McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.

2004-01-01

A magnetic circuit model is developed for a PM motor for flywheel applications. A sample motor is designed and modeled. Motor configuration and selection of materials is discussed, and the choice of winding configuration is described. A magnetic circuit model is described, which includes the stator back iron, rotor yoke, permanent magnets, air gaps and the stator teeth. Iterative solution of this model yields flux linkages, back EMF, torque, power, and radial force at the rotor caused by eccentricity. Calculated radial forces are then used to determine motor negative stiffness.

A Study on the Evaluation of Life and Development of Diagnosis System of Generator

Energy Technology Data Exchange (ETDEWEB)

Ji, P.S.; Ju, Y.H.; Park, J.J.; Kim, H.D. [Korea Electric Power Research Insitute, Taejeon (Korea, Republic of); Kim, Y.J.; Kim, J.B.; Hwang, D.H. [Korea Electrotechnology Research Institute, Changweon (Korea, Republic of)

1997-12-31

The following Research and Development activities have been performed by KEPRI and KERI for the safe and realiable operation of generators. They can also help to establish the economical scheduling for commissioning and to extend the lives of generators. (1) The optimal diagnosis system and techniques which can be applied to a generator while running are developed. (2) The novel criterion for degradation of stator winding insulation is established. (3) The database for stator winding diagnosis and development of expert system for life assessment is built. (author). 86 refs., 239 figs., 86 tabs.

Detection of Failure in Asynchronous Motor Using Soft Computing Method

Science.gov (United States)

Vinoth Kumar, K.; Sony, Kevin; Achenkunju John, Alan; Kuriakose, Anto; John, Ano P.

2018-04-01

This paper investigates the stator short winding failure of asynchronous motor also their effects on motor current spectrums. A fuzzy logic approach i.e., model based technique possibly will help to detect the asynchronous motor failure. Actually, fuzzy logic similar to humanoid intelligent methods besides expected linguistic empowering inferences through vague statistics. The dynamic model is technologically advanced for asynchronous motor by means of fuzzy logic classifier towards investigate the stator inter turn failure in addition open phase failure. A hardware implementation was carried out with LabVIEW for the online-monitoring of faults.

Cogging Torque Reduction in Brushless DC Motors Using Slot-Opening Shift

Directory of Open Access Journals (Sweden)

SAIED, S. A.

2009-02-01

Full Text Available In this paper, two new methods for the stator skew are introduced. In contrary with the conventional stator skew, this paper is concentrate on the slot-opening skew. The simula-tion result by finite element shows a considerable reduction in the cogging torque of the motors, the new methods are applied to. Moreover the simulations justify that the back-EMF shape remains trapezoidal for various skew angles in contrary with that in the conventional skew, this fact makes the method highly applicable in BLDC motors.

Development of Interior Permanent Magnet Motors with Concentrated Windings for Reducing Magnet Eddy Current Loss

Science.gov (United States)

Yamazaki, Katsumi; Kanou, Yuji; Fukushima, Yu; Ohki, Shunji; Nezu, Akira; Ikemi, Takeshi; Mizokami, Ryoichi

In this paper, we present the development of interior magnet motors with concentrated windings, which reduce the eddy current loss of the magnets. First, the mechanism of the magnet eddy current loss generation is investigated by a simple linear magnetic circuit. Due to the consideration, an automatic optimization method using an adaptive finite element method is carried out to determine the stator and rotor shapes, which decrease the eddy current loss of the magnet. The determined stator and rotor are manufactured in order to proof the effectiveness by the measurement.

None of the Rotor Residues of F1-ATPase Are Essential for Torque Generation

Science.gov (United States)

Chiwata, Ryohei; Kohori, Ayako; Kawakami, Tomonari; Shiroguchi, Katsuyuki; Furuike, Shou; Adachi, Kengo; Sutoh, Kazuo; Yoshida, Masasuke; Kinosita, Kazuhiko

2014-01-01

F1-ATPase is a powerful rotary molecular motor that can rotate an object several hundred times as large as the motor itself against the viscous friction of water. Forced reverse rotation has been shown to lead to ATP synthesis, implying that the mechanical work against the motor’s high torque can be converted into the chemical energy of ATP. The minimal composition of the motor protein is α3β3γ subunits, where the central rotor subunit γ turns inside a stator cylinder made of alternately arranged α3β3 subunits using the energy derived from ATP hydrolysis. The rotor consists of an axle, a coiled coil of the amino- and carboxyl-terminal α-helices of γ, which deeply penetrates the stator cylinder, and a globular protrusion that juts out from the stator. Previous work has shown that, for a thermophilic F1, significant portions of the axle can be truncated and the motor still rotates a submicron sized bead duplex, indicating generation of up to half the wild-type (WT) torque. Here, we inquire if any specific interactions between the stator and the rest of the rotor are needed for the generation of a sizable torque. We truncated the protruding portion of the rotor and replaced part of the remaining axle residues such that every residue of the rotor has been deleted or replaced in this or previous truncation mutants. This protrusionless construct showed an unloaded rotary speed about a quarter of the WT, and generated one-third to one-half of the WT torque. No residue-specific interactions are needed for this much performance. F1 is so designed that the basic rotor-stator interactions for torque generation and control of catalysis rely solely upon the shape and size of the rotor at very low resolution. Additional tailored interactions augment the torque to allow ATP synthesis under physiological conditions. PMID:24853745

Radial electromagnetic force calculation of induction motor based on multi-loop theory

Directory of Open Access Journals (Sweden)

HE Haibo

2017-12-01

Full Text Available [Objectives] In order to study the vibration and noise of induction motors, a method of radial electromagnetic force calculation is established on the basis of the multi-loop model.[Methods] Based on the method of calculating air-gap magneto motive force according to stator and rotor fundamental wave current, the analytic formulas are deduced for calculating the air-gap magneto motive force and radial electromagnetic force generated in accordance with any stator winding and rotor conducting bar current. The multi-loop theory and calculation method for the electromagnetic parameters of a motor are introduced, and a dynamic simulation model of an induction motor built to achieve the current of the stator winding and rotor conducting bars, and obtain the calculation formula of radial electromagnetic force. The radial electromagnetic force and vibration are then estimated.[Results] The experimental results indicate that the vibration acceleration frequency and amplitude of the motor are consistent with the experimental results.[Conclusions] The results and calculation method can support the low noise design of converters.

Static Eccentricity Fault Recognition in Three-Phase Line Start Permanent Magnet Synchronous Motor Using Finite Element Method

Directory of Open Access Journals (Sweden)

Mahdi Karami

2014-01-01

Full Text Available This paper is dedicated to investigating static eccentricity in a three-phase LSPMSM. The modeling of LSPMSM with static eccentricity between stator and rotor is developed using finite element method (FEM. The analytical expression for the permeance and flux components of nonuniform air-gap due to static eccentricity fault is discussed. Various indexes for static eccentricity detection using stator current signal of IM and permanent magnet synchronous motor (PMSM are presented. Since LSPMSM is composed of a rotor which is a combination of these two motors, the ability of these features is evaluated for static eccentricity diagnosis in LSPMSM. The simulated stator current signal of LSPMSM in the presence of static eccentricity is analyzed in frequency domain using power spectral density (PSD. It is demonstrated that static eccentricity fault generates a series of low frequency harmonic components in the form of sidebands around the fundamental frequency. Moreover, the amplitudes of these components increase in proportion to the fault severity. According to the mentioned observations, an accurate frequency pattern is specified for static eccentricity detection in three-phase LSPMSM.

Gearless wind power generator

Energy Technology Data Exchange (ETDEWEB)

Soederlund, L.; Ridanpaeae, P.; Vihriaelae, H.; Peraelae, R. [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism

1998-10-01

In the project a 100 kW axial flux permanent magnet wind power generator has been designed. The toroidal stator with air gap winding is placed between two rotating discs with permanent magnets. The magnet material is NdBFe due to its excellent magnetic properties compared to other materials. This type of topology enables a very large number of poles compared to conventional machine of the same size. A large number of poles is required to achieve a low rotational speed and consequently a direct driven system. The stator winding is formed by rectangular coils. The end winding is very short leading to small resistive losses. On the other hand, the absence of iron teeth causes eddy current losses in the conductors. These can be restricted to an acceptable level by keeping the wire diameter and flux density small. This means that the number of phases should be large. Several independent three phase systems may be used. The toothless stator also means that the iron losses are small and there exists no cogging torque

Analytical prediction of the unsteady lift on a rotor caused by downstream struts

Science.gov (United States)

Taylor, A. C., III; Ng, W. F.

1987-01-01

A two-dimensional, inviscid, incompressible procedure is presented for predicting the unsteady lift on turbomachinery blades caused by the upstream potential disturbance of downstream flow obstructions. Using the Douglas-Neumann singularity superposition potential flow computer program to model the downstream flow obstructions, classical equations of thin airfoil theory are then employed, to compute the unsteady lift on the upstream rotor blades. The method is applied to a particular geometry which consists of a rotor, a downstream stator, and downstream struts which support the engine casing. Very good agreement between the Douglas-Neumann program and experimental measurements was obtained for the downstream stator-strut flow field. The calculations for the unsteady lift due to the struts were in good agreement with the experiments in showing that the unsteady lift due to the struts decays exponentially with increased axial separation of the rotor and the struts. An application of the method showed that for a given axial spacing between the rotor and the strut, strut-induced unsteady lift is a very weak function of the axial or circumferential position of the stator.

Aerodynamic Analysis and Three-Dimensional Redesign of a Multi-Stage Axial Flow Compressor

Directory of Open Access Journals (Sweden)

Tao Ning

2016-04-01

Full Text Available This paper describes the introduction of three-dimension (3-D blade designs into a 5-stage axial compressor with multi-stage computational fluid dynamic (CFD methods. Prior to a redesign, a validation study is conducted for the overall performance and flow details based on full-scale test data, proving that the multi-stage CFD applied is a relatively reliable tool for the analysis of the follow-up redesign. Furthermore, at the near stall point, the aerodynamic analysis demonstrates that significant separation exists in the last stator, leading to the aerodynamic redesign, which is the focus of the last stator. Multi-stage CFD methods are applied throughout the three-dimensional redesign process for the last stator to explore their aerodynamic improvement potential. An unconventional asymmetric bow configuration incorporated with leading edge re-camber and re-solidity is employed to reduce the high loss region dominated by the mainstream. The final redesigned version produces a 13% increase in the stall margin while maintaining the efficiency at the design point.

Amorphous and Nanocomposite Materials for Energy-Efficient Electric Motors

Science.gov (United States)

Silveyra, Josefina M.; Xu, Patricia; Keylin, Vladimir; DeGeorge, Vincent; Leary, Alex; McHenry, Michael E.

2016-01-01

We explore amorphous soft-magnetic alloys as candidates for electric motor applications. The Co-rich system combines the benefits of low hysteretic and eddy-current losses while exhibiting negligible magnetostriction and robust mechanical properties. The amorphous precursors can be devitrified to form nanocomposite magnets. The superior characteristics of these materials offer the advantages of ease of handling in the manufacturing processing and low iron losses during motor operation. Co-rich amorphous ribbons were laser-cut to build a stator for a small demonstrator permanent-magnet machine. The motor was tested up to ~30,000 rpm. Finite-element analyses proved that the iron losses of the Co-rich amorphous stator were ~80% smaller than for a Si steel stator in the same motor, at 18,000 rpm (equivalent to an electric frequency of 2.1 kHz). These low-loss soft magnets have great potential for application in highly efficient high-speed electric machines, leading to size reduction as well as reduction or replacement of rare earths in permanent-magnet motors. More studies evaluating further processing techniques for amorphous and nanocomposite materials are needed.

Design of a Modular E-Core Flux Concentrating Axial Flux Machine: Preprint

Energy Technology Data Exchange (ETDEWEB)

Husain, Tausif; Sozer, Yilmaz; Husain, Iqbal; Muljadi, Eduard

2015-08-24

In this paper a novel E-Core axial flux machine is proposed. The machine has a double-stator, single-rotor configuration with flux-concentrating ferrite magnets and pole windings across each leg of an E-Core stator. E-Core stators with the proposed flux-concentrating rotor arrangement result in better magnet utilization and higher torque density. The machine also has a modular structure facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis. facilitating simpler construction. This paper presents a single-phase and a three-phase version of the E-Core machine. Case studies for a 1.1-kW, 400-rpm machine for both the single-phase and three-phase axial flux machines are presented. The results are verified through 3D finite element analysis.

A supersonic fan equipped variable cycle engine for a Mach 2.7 supersonic transport

Science.gov (United States)

Tavares, T. S.

1985-01-01

The concept of a variable cycle turbofan engine with an axially supersonic fan stage as powerplant for a Mach 2.7 supersonic transport was evaluated. Quantitative cycle analysis was used to assess the effects of the fan inlet and blading efficiencies on engine performance. Thrust levels predicted by cycle analysis are shown to match the thrust requirements of a representative aircraft. Fan inlet geometry is discussed and it is shown that a fixed geometry conical spike will provide sufficient airflow throughout the operating regime. The supersonic fan considered consists of a single stage comprising a rotor and stator. The concept is similar in principle to a supersonic compressor, but differs by having a stator which removes swirl from the flow without producing a net rise in static pressure. Operating conditions peculiar to the axially supersonic fan are discussed. Geometry of rotor and stator cascades are presented which utilize a supersonic vortex flow distribution. Results of a 2-D CFD flow analysis of these cascades are presented. A simple estimate of passage losses was made using empirical methods.

A Review of Online Partial Discharge Measurement of Large Generators

Directory of Open Access Journals (Sweden)

Yuanlin Luo

2017-10-01

Full Text Available Online partial discharge (PD measurements have long been used as an effective means to assess the condition of the stator windings of large generators. An increase in the use of PD online measurement systems during the last decade is evident. Improvements in the detection capabilities are partly the reason for the increased popularity. Another reason has been the development of digital signal processing techniques. In addition, rapid progress is being made in automated single PD source classification. However, there are still some factors hindering wider application of the system, such as the complex PD mechanism and PD pulse propagation in stator windings, the presence of detrimental noise and disturbances on-site, and multiple PD sources occurring simultaneously. To avoid repetition of past work and to provide an overview for fresh researchers in this area, this paper presents a comprehensive survey of the state-of-the-art knowledge on PD mechanism, PD pulse propagation in stator windings, PD signal detection methods and signal processing techniques. Areas for further research are also presented.

Study of an electromagnetic pump in a sodium cooled reactor. Design study of secondary sodium main pumps (Joint research)

International Nuclear Information System (INIS)

Chikazawa, Yoshitaka; Kisohara, Naoyuki; Hishida, Masahiko; Fujii, Tadashi; Konomura, Mamoru; Ara, Kuniaki; Hori, Toru; Uchida, Akihito; Nishiguchi, Youhei; Nibe, Nobuaki

2006-07-01

In the feasibility study on commercialized fast breeder cycle system, a medium scale sodium cooled reactor with 750 MW electricity has been designed. In this study, EMPs are applied to the secondary sodium main pump. The EMPs type is selected to be an annular linear induction pump (ALIP) type with double stators which is used in the 160 m 3 /min EMP demonstration test. The inner structure and electromagnetic features are decided reviewing the 160 m 3 /min EMP. Two dimensional electromagnetic fluid analyses by EAGLE code show that Rms (magnetic Reynolds number times slip) is evaluated to be 1.08 which is less than the stability limit 1.4 confirmed by the 160 m 3 /min EMP test, and the instability of the pump head is evaluated to be 3% of the normal operating pump head. Since the EMP stators are cooled by contacting coolant sodium duct, reliability of the inner structures are confirmed by temperature distribution and stator-duct contact pressure analyses. Besides, a power supply system, maintenance and repair feature and R and D plan of EMP are reported. (author)

H(+) and Na(+) are involved in flagellar rotation of the spirochete Leptospira.

Science.gov (United States)

Islam, Md Shafiqul; Morimoto, Yusuke V; Kudo, Seishi; Nakamura, Shuichi

2015-10-16

Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H(+) is used in Escherichia coli, and Na(+) is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H(+) is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na(+), though it vigorously moved even under Na(+)-free conditions. These results suggest that H(+) is preferentially used and that Na(+) is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. Copyright © 2015 Elsevier Inc. All rights reserved.

Apparatus for cooling an electric machine

Science.gov (United States)

Palafox, Pepe; Gerstler, William Dwight; Shen, Xiaochun; El-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Salasoo, Lembit

2013-07-16

Provided is an apparatus, for example, for use with a rotating electric machine, that includes a housing. The housing can include a housing main portion and a housing end portion. The housing main portion can be configured to be disposed proximal to a body portion of a stator section of an electric machine. The housing main portion can define a main fluid channel that is configured to conduct fluid therethrough. The housing end portion can receive fluid from said main fluid channel and direct fluid into contact with a winding end portion of a conductive winding of the stator section.

DESIGN METHODOLOGY OF SELF-EXCITED ASYNCHRONOUS GENERATOR

Directory of Open Access Journals (Sweden)

Berzan V.

2012-04-01

Full Text Available The paper sets out the methodology of designing an asynchronous generator with capacitive self-excitation. It is known that its design is possible on the basis of serial synchronous motor with squirrel cage rotor. With this approach, the design reworked only the stator winding of electrical machines, making it cost-effectively implement the creation of the generator. Therefore, the methodology for the design, optimization calculations, the development scheme and the stator winding excitation system gain, not only of practical interest, and may also be useful for specialists in the field of electrical machines in the design of asynchronous generators.

Generalized two axes model of a squirrel-cage induction motor for rotor fault diagnosis

Directory of Open Access Journals (Sweden)

Samir Hamdani

2008-01-01

Full Text Available A generalized two axes model of a squirrel-cage induction motor is developed This model is based on a winding function approach and the coupled magnetic circuit theory and takes into account the stator and the rotor asymmetries due to faults. This paper presents a computer simulation and experimental dynamic characteristics for a healthy induction machine, machine with one broken bar and a machine with two broken bars. The results illustrate good agreement between both simulated and experimental results. Also, the power spectral density PSD was performed to obtain a stator current spectrum.

Dynamic response of a rub-impact rotor system under axial thrust

Energy Technology Data Exchange (ETDEWEB)

An, Xueli; Zhou, Jianzhong; Xiang, Xiuqiao; Li, Chaoshun; Luo, Zhimeng [Huazhong University of Science andTechnology, College of Hydroelectric and Digitalization Engineering, Wuhan, Hubei (China)

2009-11-15

A model of a rigid rotor system under axial thrust with rotor-to-stator is developed based on the classic impact theory and is analyzed by the Lagrangian dynamics. The rubbing condition is modeled using the elastic impact-contact idealization, which consists of normal and tangential forces at the rotor-to-stator contact point. Mass eccentricity and rotating speed are used as control parameters to simulate the response of rotor system. The motions of periodic, quasi-periodic and chaotic are found in the rotor system response. Mass eccentricity plays an important role in creating chaotic phenomena. (orig.)

Propagation of Partial Discharge and Noise Pulses in Turbine Generators

DEFF Research Database (Denmark)

Henriksen, Mogens; Stone, G. C.; Kurtz, M.

1986-01-01

Changes with time in the partial discharge (PD) activity originating in a generator stator's insulation system provide information about the electrical integrity of the stator winding. It is desirable to measure PD during normal service to minimize costs. To do this successfully, the influence...... of electrical interference must be reduced. Tests are reported which characterize the nature of discharge and noise pulses when using capacitive couplers mounted on each of the phase leads and an RF current transformer mounted on the neutral lead for signal detection. Significant differences between PD...... and electrical noise have been observed....

A novel excitation assistance switched reluctance wind power generator

DEFF Research Database (Denmark)

Liu, Xiao; Park, Kiwoo; Chen, Zhe

2014-01-01

The high inductance of a general switched reluctance generator (SRG) may prevent the excitation of the magnetic field from being quickly established enough, which may further limit the output power of the SRG. A novel excitation assistance SRG (EASRG) for wind power generation is proposed...... in this paper to solve the above problem. C-shape stator cores are employed in a modular design concept for quick maintenance or replacement, and a ring-shape excitation assistant coil is sandwiched in the space between the modular stator cores. The magnetization and torque characteristics are simulated by 3-D...

Wet bar detection by using water absorption detector

International Nuclear Information System (INIS)

Kim, Hee Soo; Bae, Yong Chae; Kee, Chang Doo

2008-01-01

Water leaks in water-cooled generator stator windings can generate serious accidents such as insulation breakdown and result in unexpected sudden outages. Thus, it is important to diagnose their water absorption for effective operation of the power plant. Especially, since the capacitance values that are measured for diagnosis are very small so special diagnosis methods like stochastic theory are needed. KEPRI developed a more advanced water absorption detector and diagnosis technology for it. They were applied to a real system and the results of the water absorption test for stator windings agree with the water leak test

Implementation of an Automatic System for the Monitoring of Start-up and Operating Regimes of the Cooling Water Installations of a Hydro Generator

Directory of Open Access Journals (Sweden)

Ioan Pădureanu

2015-07-01

Full Text Available The safe operation of a hydro generator depends on its thermal regime, the basic conditions being that the temperature in the stator winding fall within the limits of the insulation class. As the losses in copper depend on the square current in the stator winding, it is necessary that the cooling water debit should be adapted to the values of these losses, so that the winding temperature falls within the range of the values prescribed in the specifications. This paper presents an efficient solution of commanding and monitoring the water cooling installations of two high-power hydro generators.

Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor

Science.gov (United States)

Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.

2016-06-01

Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.

Preliminary Experimental Results for Indirect Vector-Control of Induction Motor Drives with Forced Dynamics

Directory of Open Access Journals (Sweden)

Jan Vittek

2003-01-01

Full Text Available The contribution presents an extension of indirect vector control of electric drives employing induction motors to 'Forced Dynamic Control'. This method of control offers an accurate realisation of dynamic response profiles, which can be selected by the user. The developed system can be integrated into a drive with a shaft position encoder or a shaft sensoriess drive, in which only the stator currents are measured. The applied stator voltages are determined by a computed inverter switching algorithm. Simulation results and preliminary experimental results for indirect vector control of an idle running induction motor indicate good agreement with the theoretical predictions.

Study of blade aspect ratio on a compressor front stage aerodynamic and mechanical design report

Science.gov (United States)

Burger, G. D.; Lee, D.; Snow, D. W.

1979-01-01

A single stage compressor was designed with the intent of demonstrating that, for a tip speed and hub-tip ratio typical of an advanced core compressor front stage, the use of low aspect ratio can permit high levels of blade loading to be achieved at an acceptable level of efficiency. The design pressure ratio is 1.8 at an adiabatic efficiency of 88.5 percent. Both rotor and stator have multiple-circular-arc airfoil sections. Variable IGV and stator vanes permit low speed matching adjustments. The design incorporates an inlet duct representative of an engine transition duct between fan and high pressure compressor.

Design and Performance Test of Axial Halbach Brushless DC Motor with Power Density 1.5 Kw/Kg

Directory of Open Access Journals (Sweden)

Kevin Dwi Prasetio

2017-01-01

Full Text Available Progress of technology on electric vehicle component sector is one reason the emergence of electric vehicles at the moment. Starting from battery which has a great current density up to the automatic control systems on electric vehicles. But there are still some shortcomings of this electric vehicle components, one of which is the low value of power density of existing electric motor in the market today.On vehicles such as electric cars when Race Car Contest, energy saving problems about power density of the driving motor is very vital. This is because the total weight of the vehicle has a huge influence on the vehicle efficiency is against it. The issue is one of the reasons of the research task. In this final task is done making the design, simulation, and architecture of the Axial Halbach Brushless DC Motor. Use of system configuration on the halbach magnet to avoid the use of iron as a material cantilever rotor. By changing the material of the cantilever rotor with lighter materials such as aluminum or even carbon fibre, the value of power density electric motors can be increased. Then using the litz wire on coil stator to reduce loss-power loss due to the barriers on the coil. Coreless stator on the system and to avoid the phenomenon of cogging at the time due to low rpm style attraction magnet with iron in the core material. While the creation process begins by determining the specifications of the Axial Halbach Brushless DC motors. Then go into the design phase of the mechanical and electrical design. Who then conducted simulations to help determine other parameters such as air gap, slot turn, and magnetic orientation. The process of making a component of stator and rotor after the simulation is completed. After all the components of the rotor and stator on assembly, mounting the hall sensor is carried out to the right to position obtained by reading the signals. After the motor can spin with good motor performance, testing can be done

Experimental investigation on sandwich structure ring-type ultrasonic motor.

Science.gov (United States)

Peng, Taijiang; Shi, Hongyan; Liang, Xiong; Luo, Feng; Wu, Xiaoyu

2015-02-01

This paper presents a manufacture method for a sandwich structure Ultrasonic Motor (USM) and experiment. Two pieces of rotor clamped on a stator, and a stainless steel disk-spring is bonded on the hollow rotor disk to provide the press by a nut assembled on the shaft. The stator is made of a double-side Printed-Circuit Board (PCB) which is sawed out the ring in the center and connected on the board with three legs. On each side of the ring surface, there are electrodes connected at the same position via through hole. The three layer drive circuit for sine, cosine, and ground signal is connected on the board through each leg. There are many piezoelectric components (PZT) bonded between two electrodes and fill soldering tin on each electrode. Then PZT is welded on PCB by reflow soldering. Finally, rub the gibbous soldering tin down to the position of PZT surface makes sure the surface contacts with rotor evenly. The welding process can also be completed by Surface Mounted Technology (SMT). A prototype motor is manufactured by this method. Two B03 model shapes of the stator are obtained by the finite element analysis and the optimal frequency of the motor is 56.375 kHz measured by impedance instrument. The theoretical analysis is conducted for the relationship between the revolving speed of the USM and thickness of stator ring, number of the travelling waves, PZT amplitude, frequency and the other parameters. The experiment result shows that the maximum revolving speed is 116 RPM and the maximum torque is 25 N mm, when the actuate voltage is 200 VAC. Copyright © 2014 Elsevier B.V. All rights reserved.

Fast and accurate spectral estimation for online detection of partial broken bar in induction motors

Science.gov (United States)

Samanta, Anik Kumar; Naha, Arunava; Routray, Aurobinda; Deb, Alok Kanti

2018-01-01

In this paper, an online and real-time system is presented for detecting partial broken rotor bar (BRB) of inverter-fed squirrel cage induction motors under light load condition. This system with minor modifications can detect any fault that affects the stator current. A fast and accurate spectral estimator based on the theory of Rayleigh quotient is proposed for detecting the spectral signature of BRB. The proposed spectral estimator can precisely determine the relative amplitude of fault sidebands and has low complexity compared to available high-resolution subspace-based spectral estimators. Detection of low-amplitude fault components has been improved by removing the high-amplitude fundamental frequency using an extended-Kalman based signal conditioner. Slip is estimated from the stator current spectrum for accurate localization of the fault component. Complexity and cost of sensors are minimal as only a single-phase stator current is required. The hardware implementation has been carried out on an Intel i7 based embedded target ported through the Simulink Real-Time. Evaluation of threshold and detectability of faults with different conditions of load and fault severity are carried out with empirical cumulative distribution function.

Complete modeling of rotary ultrasonic motors actuated by traveling flexural waves

Science.gov (United States)

Bao, Xiaoqi; Bar-Cohen, Yoseph

2000-06-01

Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors are being adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and analytical tools for the design of efficient motors are being developed. A hybrid analytical model was developed to address a complete ultrasonic motor as a system. Included in this model is the influence of the rotor dynamics, which was determined experimentally to be important to the motor performance. The analysis employs a 3D finite element model to express the dynamic characteristics of the stator with piezoelectric elements and the rotor. The details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. are included to support practical USM designs. A brush model is used for the interface layer and Coulomb's law for the friction between the stator and the rotor. The theoretical predictions were corroborated experimentally for the motor. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.

A new two-phase homopolar switched reluctance motor for electric vehicle applications

Science.gov (United States)

Tsai, Mi-Ching; Huang, Chien-Chin; Huang, Zheng-Yi

2003-12-01

This paper presents a novel 2-phase homopolar switched reluctance motor (SRM), whose design successfully avoids dead-zone problems that afflict low cost 1- and/or 2-phase SRMs. Unlike conventional radial-winding-radial-gap motors, the proposed SRM has an interior stator that is of the pancake type with axial winding. Such a design allows for a high slot-fill factor and is suitable for implementation as a flat pancake-shaped stator. An efficient, compact prototype was produced with TMS320F240 DSP driving control unit. Experimental results indicate that the present SRM design has the potential to be used for electric bicycles and scooters.

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

Directory of Open Access Journals (Sweden)

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.

Axial gap rotating electrical machine

Science.gov (United States)

None

2016-02-23

Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.

A Theoretical Investigation on Rectifying Performance of a Single Motor Molecular Device

International Nuclear Information System (INIS)

Lei Hui; Tan Xun-Qiong

2015-01-01

We report ab initio calculations of the transport behavior of a phenyl substituted molecular motor. The calculated results show that the transport behavior of the device is sensitive to the rotation degree of the rotor part. When the rotor part is parallel with the stator part, a better rectifying performance can be found in the current-voltage curve. However, when the rotor part revolves to vertical with the stator part, the currents in the positive bias region decrease slightly. More importantly, the rectifying performance disappears. Thus this offers us a new method to modulate the rectifying behavior in molecular devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Unsteady effects at the interface between impeller-vaned diffuser in a low pressure centrifugal compressor

Directory of Open Access Journals (Sweden)

Mihai Leonida NICULESCU

2013-03-01

Full Text Available In this paper, Proper Orthogonal Decomposition (POD is applied to the analysis of the unsteady rotor-stator interaction in a low-pressure centrifugal compressor. Numerical simulations are carried out through finite volumes method using the Unsteady Reynolds-Averaged Navier-Stokes Equations (URANS model. Proper Orthogonal Decomposition allows an accurate reconstruction of flow field using only a small number of modes; therefore, this method is one of the best tools for data storage. The POD results and the data obtained by the Adamczyk decomposition are compared. Both decompositions show the behavior of unsteady rotor-stator interaction, but the POD modes allow quantifying better the numerical errors.

A novel permanent maglev rotary LVAD with passive magnetic bearings.

Science.gov (United States)

Qian, K X; Yuan, H Y; Zeng, P; Ru, W M

2005-01-01

It has been widely acknowledged that permanent maglev cannot achieve stability; however, the authors have discovered that stable permanent maglev is possible under the effect of a combination of passive magnetic and nonmagnetic forces. In addition, a rotary left ventricular assist device (LVAD) with passive magnetic bearings has been developed. It is a radially driven impeller pump, having a rotor and a stator. The rotor consists of driven magnets and impeller; the motor coil and pump housing form the stator. Two passive magnetic bearings counteract the attractive force between motor coil iron core and rotor magnets; the rotor thereafter can be disaffiliated from the stator and become levitated under the action of passive magnetic and haemodynamic forces. Because of the pressure difference between the outlet and the inlet of the pump, there is a small flow passing through the gap of rotor and stator, and then entering the lower pressure area along the central hole of the rotor. This small flow comes to a full washout of all blood contacting surfaces in the motor. Moreover, a decreased Bernoulli force in the larger gap with faster flow produces a centring force that leads to stable levitation of the rotor. Resultantly, neither mechanical wear nor thrombosis will occur in the pump. The rotor position detection reveals that the precondition of levitation is a high rotating speed (over 3250 rpm) and a high flow rate (over 1 l min(-1)). Haemodynamic tests with porcine blood indicate that the device as a LVAD requires a rotating speed between 3500 and 4000 rpm for producing a blood flow of 4 - 6 l min(-1) against 100 mmHg mean pressure head. The egg-sized device has a weight of 200 g and an O.D. of 40 mm at its largest point.

H+ and Na+ are involved in flagellar rotation of the spirochete Leptospira

International Nuclear Information System (INIS)

Islam, Md. Shafiqul; Morimoto, Yusuke V.; Kudo, Seishi; Nakamura, Shuichi

2015-01-01

Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H + is used in Escherichia coli, and Na + is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H + is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na + , though it vigorously moved even under Na + -free conditions. These results suggest that H + is preferentially used and that Na + is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. - Highlights: • This is a study on input energy for motility in the spirochete Leptospira. • Leptospira biflexa exhibited active motility in acidic to alkaline pH. • Both H + and Na + are involved in flagellar rotation in Leptospira. • H + is a primary energy source, but Na + can secondarily enhance motility.

Numerical simulation of the unsteady and turbulent flow in a high-pressure turbine stage; Simulation numerique de l'ecoulement instationnaire et turbulent dans un etage de turbine haute pression

Energy Technology Data Exchange (ETDEWEB)

Bastin, G.

2004-09-15

The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional stator. Because the slot is represented by meshes overlapping the mesh of the smooth blade, the Chimera method is chosen. This method makes it possible computations with overlapping meshes. The comparison with the experimental data, on these two first computations has validated this strategy to represent such slots. The tridimensional simulation of a single stator with taking account of the cooling is then realized. It showed the complex and tridimensional aspects of the main flow with focus on the influence of the cooling system. Finally two steady computations, without and with cooling, and an unsteady computation without cooling are carried out on a high pressure turbine stage. The comparison with the experimental data obtained in the frame of the European Brite-Euram program is made. These results make it possible to determine the effect of the cooling on the flow in a turbine stage. (authors)

H{sup +} and Na{sup +} are involved in flagellar rotation of the spirochete Leptospira

Energy Technology Data Exchange (ETDEWEB)

Islam, Md. Shafiqul [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Morimoto, Yusuke V. [Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874 (Japan); Graduate School of Frontier BioSciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kudo, Seishi [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Nakamura, Shuichi, E-mail: naka@bp.apph.tohoku.ac.jp [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Graduate School of Frontier BioSciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2015-10-16

Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H{sup +} is used in Escherichia coli, and Na{sup +} is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H{sup +} is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na{sup +}, though it vigorously moved even under Na{sup +}-free conditions. These results suggest that H{sup +} is preferentially used and that Na{sup +} is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. - Highlights: • This is a study on input energy for motility in the spirochete Leptospira. • Leptospira biflexa exhibited active motility in acidic to alkaline pH. • Both H{sup +} and Na{sup +} are involved in flagellar rotation in Leptospira. • H{sup +} is a primary energy source, but Na{sup +} can secondarily enhance motility.

Actuating mechanism and design of a cylindrical traveling wave ultrasonic motor using cantilever type composite transducer.

Directory of Open Access Journals (Sweden)

Yingxiang Liu

Full Text Available BACKGROUND: Ultrasonic motors (USM are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS: A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the outside surface of cylinder, four longitudinal PZT ceramics are set between the cantilevers, and four bending PZT ceramics are set on each outside surface of cantilevers. Two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder are excited by the composite transducer. In this new design, a single transducer can excite a flexural traveling wave in the cylinder. Thus, elliptical motions are achieved on the teeth. The actuating mechanism of proposed motor was analyzed. The stator was designed with FEM. The two vibration modes of stator were degenerated. Transient analysis was developed to gain the vibration characteristic of stator, and results indicate the motion trajectories of nodes on the teeth are nearly ellipses. CONCLUSIONS: The study results verify the feasibility of the proposed design. The wave excited in the cylinder isn't an ideal traveling wave, and the vibration amplitudes are inconsistent. The distortion of traveling wave is generated by the deformation of bending vibration mode of cylinder, which is caused by the coupling effect between the cylinder and transducer. Analysis results also prove that the objective motions of nodes on the teeth are three-dimensional vibrations. But, the vibration in axial direction is minute compared with the vibrations in circumferential and radial direction. The results of this paper can guide the development of this new type of motor.

Actuating mechanism and design of a cylindrical traveling wave ultrasonic motor using cantilever type composite transducer.

Science.gov (United States)

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

2010-04-02

Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the outside surface of cylinder, four longitudinal PZT ceramics are set between the cantilevers, and four bending PZT ceramics are set on each outside surface of cantilevers. Two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder are excited by the composite transducer. In this new design, a single transducer can excite a flexural traveling wave in the cylinder. Thus, elliptical motions are achieved on the teeth. The actuating mechanism of proposed motor was analyzed. The stator was designed with FEM. The two vibration modes of stator were degenerated. Transient analysis was developed to gain the vibration characteristic of stator, and results indicate the motion trajectories of nodes on the teeth are nearly ellipses. The study results verify the feasibility of the proposed design. The wave excited in the cylinder isn't an ideal traveling wave, and the vibration amplitudes are inconsistent. The distortion of traveling wave is generated by the deformation of bending vibration mode of cylinder, which is caused by the coupling effect between the cylinder and transducer. Analysis results also prove that the objective motions of nodes on the teeth are three-dimensional vibrations. But, the vibration in axial direction is minute compared with the vibrations in circumferential and radial direction. The results of this paper can guide the development of this new type of motor.

Transonic Axial Splittered Rotor Tandem Stator Stage

Science.gov (United States)

2016-12-01

Wennerstrom [3] admits, “It might be possible to do a credible job of optimizing splitter-vane geometry analytically by one of the time- dependent or...section were saved as a .stl file. This file was transferred to the Repetier software and printer configuration preferences were entered. A detailed...Exponent 2.0000e+00 Reference Volume Mean Control Volume Reference Pressure 1.0000e+00 [atm] Heat Transfer Model Total Energy Include Viscous

An experimental evaluation of the performance deficit of an aircraft engine starter turbine

Science.gov (United States)

Haas, J. E.; Roelke, R. J.; Hermann, P.

1980-01-01

An experimental investigation is presented to determine the aerodynamic performance deficit of a 13.5 - centimeter-tip-diameter aircraft engine starter turbine. The two-phased evaluation comprised both the stator and the stage performance, and the experimental design is described in detail. Data obtained from the investigation of three honeycomb shrouds clearly showed that the filled honeycomb reached a total efficiency of 0.868, 8.2 points higher than the open honeycomb shroud, at design equivalent conditions of speed and blade-jet speed ratio. It was concluded that the use of an open honeycomb shroud caused the large performance deficit for the starter turbine. Further research is suggested to ascertain stator inlet boundary layer measurements.

A Comparative Analysis of Digital and Passive Filters for IFOC based Induction Motor Drive (EV) fed through ZSI

Science.gov (United States)

Bedi, Tarun; Heema, Dave; Singh, Dheerendra

2018-03-01

It is known that harmonics are generated in any power electronics based application. Since presence of harmonics is not desirable, it is necessary to remove the harmonics. The IFOC is based on stator current regulation, and the stator currents are sensed and used in the speed control algorithm. The current needs to be free from noise and harmonics for accurate further processing. In this paper, a passive analog filter, as well as a 50th order FIR filter is designed in MATLAB and implemented in Code Composer Studio to remove noise and distortion, and a comparative analysis has been done, for the speed control of an induction motor fed through ZSI, for electric vehicle application.

Direct measurement of A$_{b}$ and A$_{c}$ at the Z$^{0}$ pole using a lepton tag

CERN Document Server

Abe, K; Adam, I; Akagi, T; Allen, N J; Arodzero, A; Ash, William W; Aston, D; Baird, K G; Baltay, C; Band, H R; Barakat, M B; Bardon, O; Barklow, Timothy L; Bashindzhagian, G L; Bauer, J M; Bellodi, G; Ben-David, R; Benvenuti, Alberto C; Bilei, G M; Bisello, D; Blaylock, G; Bogart, J R; Bolen, B D; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Byrne, R M; Calcaterra, A; Calloway, D H; Camanzi, B; Carpinelli, M; Cassell, R; Castaldi, R; Castro, A; Cavalli-Sforza, M; Chou, A; Church, E; Cohn, H O; Coller, J A; Covery, M R; Cook, V; Cotton, R; Cowan, R F; Coyne, D G; Crawford, G; Damerell, C J S; Danielson, M N; Daoudi, M; De Groot, N; Dell'Orso, R; Dervan, P J; De Sangro, R; Dima, M; de Oliveira, A; Dong, D N; Doser, Michael; Dubois, R; Eisenstein, B I; Eschenburg, V; Etzion, E; Fahey, S; Falciai, D; Fan, C; Fernández, J P; Fero, M J; Flood, K; Frey, R; Gillman, T; Gladding, G; González, S; Goodman, E R; Hart, E L; Harton, J L; Hasan, A; Hasuko, K; Hedges, S J; Hertzbach, S S; Hildreth, M D; Huber, J; Huffer, M E; Hughes, E W; Huynh, X; Hwang, H; Iwasaki, M; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Johnson, R A; Junk, T R; Kajikawa, R; Kalelkar, M S; Kamyshkov, Yu A; Kang, H J; Karliner, I; Kawahara, H; Kim, Y D; King, R; King, M E; Kofler, R R; Krishna, N M; Kroeger, R S; Langston, M; Lath, A; Leith, D W G S; Lia, V; Lin, C J S; Liu, X; Liu, M X; Loreti, M; Lu, A; Lynch, H L; Ma, J; Mahjouri, M; Mancinelli, G; Manly, S L; Mantovani, G C; Markiewicz, T W; Maruyama, T; Masuda, H; Mazzucato, E; McKemey, A K; Meadows, B T; Menegatti, G; Messner, R; Mockett, P M; Moffeit, K C; Moore, T B; Morii, M; Müller, D; Murzin, V S; Nagamine, T; Narita, S; Nauenberg, U; Neal, H; Nussbaum, M; Oishi, N; Onoprienko, D V; Osborne, L S; Panvini, R S; Park, H; Park, C H; Pavel, T J; Peruzzi, I; Piccolo, M; Piemontese, L; Pieroni, E; Pitts, K T; Plano, R J; Prepost, R; Prescott, C Y; Punkar, G D; Quigley, J; Ratcliff, B N; Reeves, T W; Reidy, J; Reinertsen, P L; Rensing, P E; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T L; Schindler, R H; Schumm, B A; Schwiening, J; Sen, S; Serbo, V V; Shaevitz, M H; Shank, J T; Shapiro, G; Sherden, D J; Shmakov, K D; Simopoulos, C; Sinev, N B; Smith, S R; Smy, M B; Snyder, J A; Stängle, H; Stahl, A; Stamer, P E; Steiner, R; Steiner, H; Strauss, M G; Su, D; Suekane, F; Sugiyama, A; Suzuki, S; Swartz, M; Szumilo, A; Takahashi, T; Taylor, F E; Thom, J; Torrence, E; Toumbas, N K; Usher, T; Vannini, C; Vagvra, J; Vella, E N; Venuti, J P; Verdier, R; Verdini, P G; Wagner, S R; Wagner, D L; Waite, A P; Walston, S; Wang, J; Ward, C P; Watts, S J; Weidemann, A W; Weiss, E R; Whitaker, J S; White, S L; Wickens, F J; Williams, B; Williams, D C; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Wittlin, J L; Woods, M; Word, G B; Wright, T R; Wyss, J; Yamamoto, R K; Yamartino, J M; Yang, X; Yashima, J; Yellin, S J; Young, C C; Yuta, H; Zapalac, G H; Zdarko, R W; Zhou, J

1999-01-01

The parity violation parameters A/sub b/ and A/sub c/ of the Zbb and Zcc couplings have been measured directly, using the polar angle dependence of the Z/sup 0/-pole polarized cross sections. Bottom and charmed hadrons were tagged via semileptonic decays. Both the muon and electron identification algorithms take advantage of new multivariate techniques, incorporating for the first time information from the SLD Cerenkov ring imaging detector. Based on the 1993-1995 SLD sample of 150000 Z/sup 0/ decays produced with highly polarized electron beams, we measure A/sub b/=0.910+or-0.068(stat)+or- 0.037(syst), A/sub c /=0.642+or-0.110(stat)+or-0.063(syst). (20 refs).

Gas turbine engine with supersonic compressor

Science.gov (United States)

Roberts, II, William Byron; Lawlor, Shawn P.

2015-10-20

A gas turbine engine having a compressor section using blades on a rotor to deliver a gas at supersonic conditions to a stator. The stator includes one or more of aerodynamic ducts that have converging and diverging portions for deceleration of the gas to subsonic conditions and to deliver a high pressure gas to combustors. The aerodynamic ducts include structures for changing the effective contraction ratio to enable starting even when designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of two to one (2:1) or more, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

Device for district heating with utilization of waste heat from power plants

International Nuclear Information System (INIS)

Korek, J.

1976-01-01

In order to utilize the waste heat developing in power plants - especially in nuclear power plants - the author suggests to lead the waste heat of the coolers for oil (which the bearings are lubricated with), hydrogen (which serves for the stator rotor-cooling), and the stator cooling water to the circulating district heating water and to arrange these heat exchangers one behind another or parallel to each other in the water circuit of the district heating system. The oil cooler of the engine transformer is also connected with the circulation of the district heating water. The runback water of the district heating network could thus be heated from approx. 40 0 C up to 65 0 C. (UA) [de

Check valve

Science.gov (United States)

Upton, H.A.; Garcia, P.

1999-08-24

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs.

Numerical and Computational Analysis of a New Vertical Axis Wind Turbine, Named KIONAS

Directory of Open Access Journals (Sweden)

Eleni Douvi

2017-01-01

Full Text Available This paper concentrates on a new configuration for a wind turbine, named KIONAS. The main purpose is to determine the performance and aerodynamic behavior of KIONAS, which is a vertical axis wind turbine with a stator over the rotor and a special feature in that it can consist of several stages. Notably, the stator is shaped in such a way that it increases the velocity of the air impacting the rotor blades. Moreover, each stage’s performance can be increased with the increase of the total number of stages. The effects of wind velocity, the various numbers of inclined rotor blades, the rotor diameter, the stator’s shape and the number of stages on the performance of KIONAS were studied. A FORTRAN code was developed in order to predict the power in several cases by solving the equations of continuity and momentum. Subsequently, further knowledge on the flow field was obtained by using a commercial Computational Fluid Dynamics code. Based on the results, it can be concluded that higher wind velocities and a greater number of blades produce more power. Furthermore, higher performance was found for a stator with curved guide vanes and for a KIONAS configuration with more stages.

Investigation of flow in axial turbine stage without shroud-seal

Directory of Open Access Journals (Sweden)

Straka Petr

2015-01-01

Full Text Available This article deals with investigation of the influence of the radial gaps on the efficiency of the axial turbine stage. The investigation was carried out for the axial stage of the low-power turbine with the drum-type rotor without the shroud. In this configuration the flow through the radial gap under the hub-end of the stator blades and above the tip-end of the rotor blades leads to generation of the strong secondary flows, which decrease the efficiency of the stage. This problem was studied by experiment as well as by numerical modelling. The experiment was performed on the test rig equipped with the water brake dynamometer, torque meter and rotatable stator together with the linear probe manipulator. Numerical modelling was carried out for both the steady flow using the ”mixing plane” interface and the unsteady flow using the ”sliding mesh” interface between the stator and rotor wheels. The influence of the radial gap was studied in two configuration a positive and b negative overlapping of the tip-ends of the rotor blades. The efficiency of the axial stage in dependence on the expansion ratio, velocity ratio and the configuration as well as the details of the flow fields are presented in this paper.

Influence of delayed excitation on vibrations of turbine blades couple

Directory of Open Access Journals (Sweden)

Půst L.

2013-06-01

Full Text Available In the presented paper, the computational model of the turbine blade couple is investigated with the main attention to the influence two harmonic excitation forces, having the same frequency and amplitude but with moderate delay in time. Time delay between the exciting harmonic forces depends on the revolutions of bladed disk, on the number of blades on a rotating disk and on the number of stator blades. The reduction of resonance vibrations realized by means of dry friction between the shroud blade-heads increases roughly proportional to the difference of stator and rotor blade-numbers and also to the magnitude of dry friction force. From the analysis of blade couple with direct contact it was proved that the increase of friction forces causes decrease of resonance peaks, but the influence of elastic micro-deformations in the contact surfaces (modeled e.g. by the modified Coulomb dry friction law is rather small. Analysis of a blade couple with a friction element shows that the lower number of stator blades has negligible influence on the amplitudes of both blades, but decreases amplitudes of the friction element oscillations. Similarly the increase of friction forces causes a decrease of resonance peaks, but an increase of friction element amplitudes.

Upgrading primary heat transport pump seals

International Nuclear Information System (INIS)

Graham, T.; Metcalfe, R.; Rhodes, D.; McInnes, D.

1995-01-01

Changes in the operating environment at the Bruce-A Nuclear Generating Station created the need for an upgraded Primary Heat Transport Pump (PHTP) seal. In particular, the requirement for low pressure running during more frequent start-ups exposed a weakness of the CAN2 seal and reduced its reliability. The primary concern at Bruce-A was the rotation of the CAN2 No. 2 stators in their holders. The introduction of low pressure running exacerbated this problem, giving rapid wear of the stator back face, overheating, and thermocracking. In addition, the resulting increase in friction between the stator and its holder increased stationary-side hysteresis and thereby changed the seal characteristic to the point where interseal pressure oscillations became prevalent. The resultant increased hysteresis also led to hard rubbing of the seal faces during temperature transients. An upgraded seal was required for improved reliability to avoid forced outages and to reduce maintenance costs. This paper describes this upgraded 'replacement seal' and its performance history. In spite of the 'teething' problems detailed in this paper, there have been no forced outages due to the replacement seal, and in the words of a seal maintenance worker at Bruce-A, 'it allows me to go home and sleep at night instead of worrying about seal failures.' (author)

Stability Analysis and Control of DFIG Based Wind Turbine Using FBC Strategy

Directory of Open Access Journals (Sweden)

Majid Tavoosi

2013-10-01

Full Text Available Doubly fed induction generator has numerous advantages in wind power generation over other types of generators. Once a DFIG is subjected to a large voltage dip, a large rotor voltage induces in the rotor windings. This leads to a large transient current in rotor circuit and the dc-link overvoltage, and may block power electronic converter operation. This paper first discusses dynamic modeling of DFIG wind turbines with the stator flux orientation. Then, by small signal analysis, it is found that the dynamic behavior of the DFIG based WT during voltage dip, is strongly affected by the stator dynamics. Next, a nonlinear control strategy based on flatness is proposed to improve the DFIG transient performance. The main interest of this control method is the possibility to define the behavior of the state variable system in the steady state as well as in transients. Since the DFIG electrical dynamics are nonlinear; better control performance is achieved with nonlinear control, compared with the linear control scheme. The proposed approach stabilizes the stator dynamics through rotor and grid side filter voltage control. The results of time domain simulations validate the effectiveness the nonlinear control strategy during voltage dip of generator terminal.

Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

Directory of Open Access Journals (Sweden)

Fan Xiao

2015-09-01

Full Text Available During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs.

A double-superconducting axial bearing system for an energy storage flywheel model

Science.gov (United States)

Deng, Z.; Lin, Q.; Ma, G.; Zheng, J.; Zhang, Y.; Wang, S.; Wang, J.

2008-02-01

The bulk high temperature superconductors (HTSCs) with unique flux-pinning property have been applied to fabricate two superconducting axial bearings for an energy storage flywheel model. The two superconducting axial bearings are respectively fixed at two ends of the vertical rotational shaft, whose stator is composed of seven melt-textured YBa2Cu3O7-x (YBCO) bulks with diameter of 30 mm, height of 18 mm and rotor is made of three cylindrical axial-magnetized NdFeB permanent magnets (PM) by superposition with diameter of 63 mm, height of 27 mm. The experimental results show the total levitation and lateral force produced by the two superconducting bearings are enough to levitate and stabilize the 2.4 kg rotational shaft. When the two YBCO stators were both field cooled to the liquid nitrogen temperature at respective axial distances above or below the PM rotor, the shaft could be automatically levitated between the two stators without any contact. In the case of a driving motor, it can be stably rotated along the central axis besides the resonance frequency. This double-superconducting axial bearing system can be used to demonstrate the flux-pinning property of bulk HTSC for stable levitation and suspension and the principle of superconducting flywheel energy storage system to visitors.

A novel in-plane mode rotary ultrasonic motor

Directory of Open Access Journals (Sweden)

Lu Xiaolong

2014-04-01

Full Text Available Ultrasonic motors have the merits of high ratio of torque to volume, high positioning precision, intrinsic holding torque, etc., compared to the conventional electromagnetic motors. There have been several potential applications for this type of motor in aerospace exploration, but bearings and bonding mechanism of the piezoelectric ring in the motors limit the performance of them in the space operation conditions. It is known that the Langevin type transducer has excellent energy efficiency and reliability. Hence using the Langevin type transducer in ultrasonic motors may improve the reliability of piezoelectric motors for space applications. In this study, a novel in-plane mode rotary ultrasonic motor is designed, fabricated, and characterized. The proposed motor operates in in-plane vibration mode which is excited by four Langevin-type bending vibrators separately placed around a ring-shaped stator. Two tapered rotors are assembled to the inner ring of the stator and clamped together by a screw nut. In order to make the motor more stable and convenient to fix, a thin cylindrical support is placed under the stator ring. Due to its no-bearing structure and Langevin transducer excitation, the prototype ultrasonic motor may operate well in aeronautic and astronautic environments.

Optimal Power Flow Control by Rotary Power Flow Controller

Directory of Open Access Journals (Sweden)

KAZEMI, A.

2011-05-01

Full Text Available This paper presents a new power flow model for rotary power flow controller (RPFC. RPFC injects a series voltage into the transmission line and provides series compensation and phase shifting simultaneously. Therefore, it is able to control the transmission line impedance and the active power flow through it. An RPFC is composed mainly of two rotary phase shifting transformers (RPST and two conventional (series and shunt transformers. Structurally, an RPST consists of two windings (stator and rotor windings. The rotor windings of the two RPSTs are connected in parallel and their stator windings are in series. The injected voltage is proportional to the vector sum of the stator voltages and so its amplitude and angle are affected by the rotor position of the two RPSTs. This paper, describes the steady state operation and single-phase equivalent circuit of the RPFC. Also in this paper, a new power flow model, based on power injection model of flexible ac transmission system (FACTS controllers, suitable for the power flow analysis is introduced. Proposed model is used to solve optimal power flow (OPF problem in IEEE standard test systems incorporating RPFC and the optimal settings and location of the RPFC is determined.

Free piston linear generator for low grid power generation

Directory of Open Access Journals (Sweden)

Abdalla Izzeldin

2017-01-01

Full Text Available Generating power is of great importance nowadays across the world. However, recently, the world became aware of the climatic changes due to the greenhouse effect caused by CO2 emissions and began seeking solutions to reduce the negative impact on the environment. Besides, the exhaustion of fossil fuels and their environmental impact, make it is crucial to develop clean energy sources, and efforts are focused on developing and improving the efficiency of all energy consuming systems. The tubular permanent magnet linear generators (TPMLGs are the best candidate for energy converters. Despite being suffering problem of attraction force between permanent magnets and stator teeth, to eliminate such attraction force, ironless-stator could be considered. Thus, they could waive the presence of any magnetic attraction between the moving and stator part. This paper presents the design and analysis of ironless -cored TPMLG for low grid power generation. The main advantages of this generator are the low cogging force and high efficiency. Therefore, the magnetic field computation of the proposed generator has been performed by applying a magnetic vector potential and utilizing a 2-D finite element analysis (FEA. Moreover, the experimental results for the current profile, pressure profile and velocity profile have been presented.

Experimental and Numerical Investigations of Air Cooling for a Large-Scale Motor

Directory of Open Access Journals (Sweden)

Chih-Chung Chang

2009-01-01

Full Text Available This article experimentally and numerically investigates the thermal performance of a 2350-kW completely enclosed motor, which is cooled through an air-to-air heat exchanger. The air in the heat exchanger includes external and internal flow paths. The external air driven by the rotation of the centrifugal fan goes through the heat exchanger mounted on the top of the frame. The internal air absorbs heat released from the stator and the rotor and then transfers the heat to the heat exchanger through the motion of two axial fans and the rotor. Several test rigs have been set up to measure the performance of the fan and the motor. The Fluent software package is adopted to analyze the complicated thermal-fluid interactions among the centrifugal fan, two axial fans, heat exchanger, stator, and rotor. The measured data, including the fan performance curves and the temperature profiles of the heat exchanger and the stator, show good agreement with the simulated results. The numerical calculations also show that the nonuniform external flow distribution through the heat exchanger and the air leakage between the axial fan and the rotor reduces the cooling ability of the motor. A detailed discussion is also included to improve the motor cooling performance.

Temperature estimation of induction machines based on wireless sensor networks

Directory of Open Access Journals (Sweden)

Y. Huang

2018-04-01

Full Text Available In this paper, a fourth-order Kalman filter (KF algorithm is implemented in the wireless sensor node to estimate the temperatures of the stator winding, the rotor cage and the stator core in the induction machine. Three separate wireless sensor nodes are used as the data acquisition systems for different input signals. Six Hall sensors are used to acquire the three-phase stator currents and voltages of the induction machine. All of them are processed to root mean square (rms in ampere and volt. A rotary encoder is mounted for the rotor speed and Pt-1000 is used for the temperature of the coolant air. The processed signals in the physical unit are transmitted wirelessly to the host wireless sensor node, where the KF is implemented with fixed-point arithmetic in Contiki OS. Time-division multiple access (TDMA is used to make the wireless transmission more stable. Compared to the floating-point implementation, the fixed-point implementation has the same estimation accuracy at only about one-fifth of the computation time. The temperature estimation system can work under any work condition as long as there are currents through the machine. It can also be rebooted for estimation even when wireless transmission has collapsed or packages are missing.

Pulse width modulation inverter with battery charger

Science.gov (United States)

Slicker, James M.

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Check valve

International Nuclear Information System (INIS)

Upton, H.A.; Garcia, P.

1999-01-01

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs

Effect of Reynolds Number on Separation Bubbles on Controlled-Diffusion Compressor Blades in Cascade

National Research Council Canada - National Science Library

Hobson, Garth

2001-01-01

A detailed experimental investigation of second- generation, controlled-diffusion, compressor stator blades at an off-design inlet-flow angle was performed in a low-speed cascade wind tunnel primarily...

Sensitivity of Mission Energy Consumption to Turboelectric Distributed Propulsion Design Assumptions on the N3-X Hybrid Wing Body Aircraft

Science.gov (United States)

Felder, James L.; Tong, Michael T.; Chu, Julio

2012-01-01

In a previous study by the authors it was shown that the N3-X, a 300 passenger hybrid wing body (HWB) aircraft with a turboelectric distributed propulsion (TeDP) system, was able to meet the NASA Subsonic Fixed Wing (SFW) project goal for N+3 generation aircraft of at least a 60% reduction in total energy consumption as compared to the best in class current generation aircraft. This previous study combined technology assumptions that represented the highest anticipated values that could be matured to technology readiness level (TRL) 4-6 by 2030. This paper presents the results of a sensitivity analysis of the total mission energy consumption to reductions in each key technology assumption. Of the parameters examined, the mission total energy consumption was most sensitive to changes to total pressure loss in the propulsor inlet. The baseline inlet internal pressure loss is assumed to be an optimistic 0.5%. An inlet pressure loss of 3% increases the total energy consumption 9%. However changes to reduce inlet pressure loss can result in additional distortion to the fan which can reduce fan efficiency or vice versa. It is very important that the inlet and fan be analyzed and optimized as a single unit. The turboshaft hot section is assumed to be made of ceramic matrix composite (CMC) with a 3000 F maximum material temperature. Reducing the maximum material temperature to 2700 F increases the mission energy consumption by only 1.5%. Thus achieving a 3000 F temperature in CMCs is important but not central to achieving the energy consumption objective of the N3-X/TeDP. A key parameter in the efficiency of superconducting motors and generators is the size of the superconducting filaments in the stator. The size of the superconducting filaments in the baseline model is assumed to be 10 microns. A 40 micron filament, which represents current technology, results in a 200% increase in AC losses in the motor and generator stators. This analysis shows that for a system with 40

Unsteady Aerodynamics & Aeromechanics of Multi-Stage Turbomachinery Blading

National Research Council Canada - National Science Library

Fleeter, Sanford

2002-01-01

.... A benchmark-standard multistage transonic research compressor was developed by modifying the Purdue High-Speed Axial Compressor to feature new IGV and stator rows representative of modern high pressure compressors...

Electronically commutated motors for vehicle applications

Science.gov (United States)

Echolds, E. F.

1980-02-01

Two permanent magnet electronically commutated motors for electric vehicle traction are discussed. One, based on existing technology, produces 23 kW (peak) at 26,000 rpm, and 11 kW continuous at 18,000 rpm. The motor has a conventional design: a four-pole permanent magnet rotor and a three-phase stator similar to those used on ordinary induction motors. The other, advanced technology motor, is rated at 27 kW (peak) at 14,000 rpm, and 11 kW continuous at 10,500 rpm. The machine employs a permanent magnet rotor and a novel ironless stator design in an axial air gap, homopolar configuration. Comparison of the new motors with conventional brush type machines indicates potential for substantial cost savings.

Integration of a finite element generator model into a simulated HVDC connected system

Energy Technology Data Exchange (ETDEWEB)

Preston, T W; Sturgess, J P [GEC Alsthom Engineering Research Center, Stafford (United Kingdom)

1994-12-31

Within most system analysis programs generators and motors are represented by an equivalent circuit model either a 2-axis model for both stators and rotor or a three-phase model of the stator and a two-axis model of the rotor. This may be adequate under certain operating conditions such as steady-state or some symmetrical faults but for inverter-fed motors or generators feeding into a rectified load a more rigorous model of the machine is required. This paper describes the theory and development of such a model, its integration with the power electronics and application to 6-pulse and 12-pulse converters, the latter being appropriate in systems similar to HVDC unit connection. (author) 5 refs., 16 figs.

The Virtual Resistance Control Strategy for HVRT of Doubly Fed Induction Wind Generators Based on Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Zhen Xie

2014-01-01

Full Text Available Grid voltage swell will cause transient DC flux component in the doubly fed induction generator (DFIG stator windings, creating serious stator and rotor current and torque oscillation, which is more serious than influence of the voltage dip. It is found that virtual resistance manages effectively to suppress rotor current and torque oscillation, avoid the operation of crowbar circuit, and enhance its high voltage ride through technology capability. In order to acquire the best virtual resistance value, the excellent particle library (EPL of dynamic particle swarm optimization (PSO algorithm is proposed. It takes the rotor voltage and rotor current as two objectives, which has a fast convergence performance and high accuracy. Simulation and experimental results verify the effectiveness of the virtual resistance control strategy.

Vertical hydraulic generators experience with dynamic air gap monitoring

International Nuclear Information System (INIS)

Pollock, G.B.; Lyles, J.F.

1992-01-01

Until recently, dynamic monitoring of the rotor to stator air gap of hydraulic generators was not practical. Cost effective and reliable dyamic air gap monitoring equipment has been developed in recent years. Dynamic air gap monitoring was originally justified because of the desire of the owner to minimize the effects of catastrophic air gap failure. However, monitoring air gaps on a time basis has been shown to be beneficial by assisting in the assessment of hydraulic generator condition. The air gap monitor provides useful information on rotor and stator condition and generator vibration. The data generated by air gap monitors will assist managers in the decision process with respect to the timing and extent of required maintenance for a particular generating unit

A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

Science.gov (United States)

Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

2014-05-01

This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

Efficient operation of anisotropic synchronous machines for wind energy systems

International Nuclear Information System (INIS)

Eldeeb, Hisham; Hackl, Christoph M.; Kullick, Julian

2016-01-01

This paper presents an analytical solution for the Maximum-Torque-per-Ampere (MTPA) operation of synchronous machines (SM) with anisotropy and magnetic cross-coupling for the application in wind turbine systems and airborne wind energy systems. For a given reference torque, the analytical MTPA solution provides the optimal stator current references which produce the desired torque while minimizing the stator copper losses. From an implementation point of view, the proposed analytical method is appealing in terms of its fast online computation (compared to classical numerical methods) and its efficiency enhancement of the electrical drive system. The efficiency of the analytical MTPA operation, with and without consideration of cross-coupling, is compared to the conventional method with zero direct current. (paper)

Experimental Investigation of Vortex Shedding in Flow Over Second-Generation, Controlled-Diffusion, Compressor Blades in Cascade

National Research Council Canada - National Science Library

Brown, Peter

2002-01-01

An investigation of vortex shedding downstream of a cascade of second-generation, controlled-diffusion, compressor stator blades, at off-design inlet-flow angles of 31, 33 and 35 degrees and Reynolds...

Low AC-Loss Superconducting Cable Technology for Electric Aircraft Propulsion, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The availability of low AC loss magnesium diboride (MgB2) superconducting wires enables much lighter weight superconducting stator coils than with any other metal or...

Lightweight linear alternators with and without capacitive tuning

Science.gov (United States)

Niedra, Janis M.

1993-06-01

Permanent magnet excited linear alternators rated tens of kW and coupled to free-piston Stirling engines are presently viewed as promising candidates for long term generation of electric power in both space and terrestrial applications. Series capacitive cancellation of the internal inductive reactance of such alternators was considered a viable way to both increase power extraction and to suppress unstable modes of the thermodynamic oscillation. Idealized toroidal and cylindrical alternator geometries are used for a comparative study of the issues of specific mass and capacitive tuning, subject to stability criteria. The analysis shows that the stator mass of an alternator designed to be capacitively tuned is always greater than the minimum achievable stator mass of an alternator designed with no capacitors, assuming equal utilization of materials ratings and the same frequency and power to a resistive load. This conclusion is not substantially altered when the usually lesser masses of the magnets and of any capacitors are added. Within the reported stability requirements and under circumstances of normal materials ratings, this study finds no clear advantage to capacitive tuning. Comparative plots of the various constituent masses are presented versus the internal power factor taken as a design degree of freedom. The explicit formulas developed for stator core, coil, capacitor, and magnet masses and for the degree of magnet utilization provide useful estimates of scaling effects.

Temperature Dependences of Torque Generation and Membrane Voltage in the Bacterial Flagellar Motor

Science.gov (United States)

Inoue, Yuichi; Baker, Matthew A.B.; Fukuoka, Hajime; Takahashi, Hiroto; Berry, Richard M.; Ishijima, Akihiko

2013-01-01

In their natural habitats bacteria are frequently exposed to sudden changes in temperature that have been shown to affect their swimming. With our believed to be new methods of rapid temperature control for single-molecule microscopy, we measured here the thermal response of the Na+-driven chimeric motor expressed in Escherichia coli cells. Motor torque at low load (0.35 μm bead) increased linearly with temperature, twofold between 15°C and 40°C, and torque at high load (1.0 μm bead) was independent of temperature, as reported for the H+-driven motor. Single cell membrane voltages were measured by fluorescence imaging and these were almost constant (∼120 mV) over the same temperature range. When the motor was heated above 40°C for 1–2 min the torque at high load dropped reversibly, recovering upon cooling below 40°C. This response was repeatable over as many as 10 heating cycles. Both increases and decreases in torque showed stepwise torque changes with unitary size ∼150 pN nm, close to the torque of a single stator at room temperature (∼180 pN nm), indicating that dynamic stator dissociation occurs at high temperature, with rebinding upon cooling. Our results suggest that the temperature-dependent assembly of stators is a general feature of flagellar motors. PMID:24359752

CALCULATION OF INDUCTANCE OF THE INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR

Directory of Open Access Journals (Sweden)

Phyong Le Ngo

2017-01-01

Full Text Available Interior permanent magnet synchronous motor (IPMSM refers to salient-pole synchronous motors, characterized by inequality of inductances of longitudinal (d and transverse (q axes. Electromagnetic torque of IPMSM consists of two components: active torque and reactive torque; the latter depends on inductances of d and q axes. An analytical method to calculate own inductances and mutual inductances of a three-phase IPMSM is presented. Distributed windings of the stator are substituted by equivalent sine distributed windings. An interior permanent magnets rotor is substituted by an equivalent salient-pole rotor. Sections of a magnetic circuit comprising interior permanent magnets, air barriers and steel bridges are substituted by equivalent air-gap. The expressions of the magnetic induction created by current of the stator windings at each point of the air gap as well as of magnetic flux linkage of the stator windings have been obtained. The equations of the self-inductances of phases A, B, C, and of inductance of mutual induction are determined from magnetic flux linkage. The inductance of the d and q axes have been obtained as a result of transformation of the axes abc–dq. The results obtained with the use of the proposed analytical method and the finite element method are presented in the form of a graph; the calculations that have been obtained by these two methods were compared. 

A Complete Design of a Rare Earth Metal-Free Permanent Magnet Generator

Directory of Open Access Journals (Sweden)

Petter Eklund

2014-05-01

Full Text Available The price of rare-earth metals used in neodymium-iron-boron (NdFeB permanent magnets (PMs has fluctuated greatly recently. Replacing the NdFeB PMs with more abundant ferrite PMs will avoid the cost insecurity and insecurity of supply. Ferrite PMs have lower performance than NdFeB PMs and for similar performance more PM material has to be used, requiring more support structure. Flux concentration is also necessary, for example, by a spoke-type rotor. In this paper the rotor of a 12 kW NdFeB PM generator was redesigned to use ferrite PMs, reusing the existing stator and experimental setup. Finite element simulations were used to calculate both electromagnetic and mechanical properties of the design. Focus was on mechanical design and feasibility of construction. The result was a design of a ferrite PM rotor to be used with the old stator with some small changes to the generator support structure. The new generator has the same output power at a slightly lower voltage level. It was concluded that it is possible to use the same stator with either a NdFeB PM rotor or a ferrite PM rotor. A ferrite PM generator might require a larger diameter than a NdFeB generator to generate the same voltage.

Performance Comparison of Conventional Synchronous Reluctance Machines and PM-Assisted Types with Combined Star–Delta Winding

Directory of Open Access Journals (Sweden)

Mohamed Nabil Fathy Ibrahim

2017-09-01

Full Text Available This paper compares four prototype Synchronous Reluctance Motors (SynRMs having an identical geometry of iron lamination stacks in the stator and rotor. Two different stator winding layouts are employed: a conventional three-phase star connection and a combined star–delta winding. In addition, two rotors are considered: a conventional rotor without magnets and a rotor with ferrite magnets. The performance of the four SynRMs is evaluated using a two-dimensional (2D Finite Element Model (FEM. For the same copper volume and current, the combined star–delta-connected stator with Permanent Magnets (PMs in the rotor corresponds to an approximately 22% increase in the output torque at rated current and speed compared to the conventional machine. This improvement is mainly thanks to adding ferrite PMs in the rotor as well as to the improved winding factor of the combined star–delta winding. The torque gain increases up to 150% for low current. Moreover, the rated efficiency is 93.60% compared to 92.10% for the conventional machine. On the other hand, the impact on the power factor and losses of SynRM when using the star–delta windings instead of the star windings is merely negligible. The theoretical results are experimentally validated using four identical prototype machines with identical lamination stacks but different rotors and winding layouts.

Unobstructed particle image velocimetry measurements within an axial turbo-pump using liquid and blades with matched refractive indices

Science.gov (United States)

Uzol, O.; Chow, Y.-C.; Katz, J.; Meneveau, C.

2002-08-01

Performing PIV measurements within complex turbomachinery with multiple blade rows is difficult due to the optical obstruction to the illuminating sheet and to the camera caused by the blades. This paper introduces a refractive index matched facility that overcomes this problem. The rotor and stator blades are made of transparent acrylic, and the working fluid has the same optical refractive index as the blades. A 64% by weight solution of sodium iodide in water is used for this purpose. This liquid has a kinematic viscosity of about 1.1×10-6 m2/s, which is almost the same as that of water enabling operation at high Reynolds numbers. Issues related to operating with this fluid such as chemical stability, variations in transmittance and solutions to these problems are discussed. This setup allows full optical access to the entire rotor and stator passages both to the laser sheet and the camera. The experiments are conducted at different streamwise locations covering the entire flow fields around the rotor, the stator, the gap between them, and the wakes behind. Vector maps of the instantaneous and phase-averaged flow fields as well as the distribution of turbulent kinetic energy are obtained. Measurements at different magnifications enable us to obtain an overview of the flow structure, as well as detailed velocity distributions in the boundary layers and in the wakes.

Aerodynamic bases and effects of new wind turbines

International Nuclear Information System (INIS)

Vrsalovic, I.; Vrsalovic, I.

2000-01-01

Wind is a clean and renewable energy sources, however having one failure: low profitability in zones of weaker potential. However, by using a new type of wind turbine built in regulable mantle's nozzle, which replaces the free air stream of wind into into programmed i.e. regulated and partially concentrated one it is possible to generate more quantities of energy from weaker and medium winds. As a result, their efficiency will be multiplied. This article will describe and show the basic elements of aerodynamical construction, stators profiles and control blades of new wind turbines, mechanism of automatic stator regulation (beside rotor regulation) as well as modified diagram of raised medium wind speeds. power calculations and diagrams are showing that new wind turbines in nozzle, of the same diameter of rotor and at same wind speeds, due to aerodynamic activity of nozzle and 'square-cube' relation in that transformation are giving 4,3 times more electric energy than the standard types. The wind speed on rotor is raising according to square of outer diameter (dv 2 ) of stator mantle while power of new turbine in nozzle is growing with cube (v 3 ) of raised speed for normal working area. The costs of construction and operation will rise like speed according square of diameter while the production and profits, like the power, are growing with cube of raised speed. (author)

Experience of decontaminating of the ventilation system electric motors and main circulation and waterside pump drive electric motors in conditions of the Chernobyl' NPP

International Nuclear Information System (INIS)

Denisov, V.I.; Karataev, B.A.; Platonov, A.I.; Potekhin, V.B.; Ryumin, G.V.; Sorokin, N.M.; Fenogenov, V.A.; Cheremshin, P.I.

1989-01-01

The ventilation system electric motor decontamination is described. In decontaminating waterside pump rotors and stators with high level of contamination was developed a procedure, eliminating corrosion action and damage of electric isolation coatings

sizing of wind powered axial flux permanent magnet alternator using

African Journals Online (AJOL)

user

2016-10-04

Oct 4, 2016 ... Keywords: Wind-Power, Axial flux, Axial Flux Permanent Machines (AFPM), Axial Flux Permanent Magnet ... energy for power generation, a high constraint is the .... arrangements as Single-Rotor Single-Stator Structure.

Experimental and numerical investigation of hydro power generator ventilation

Science.gov (United States)

Jamshidi, H.; Nilsson, H.; Chernoray, V.

2014-03-01

Improvements in ventilation and cooling offer means to run hydro power generators at higher power output and at varying operating conditions. The electromagnetic, frictional and windage losses generate heat. The heat is removed by an air flow that is driven by fans and/or the rotor itself. The air flow goes through ventilation channels in the stator, to limit the electrical insulation temperatures. The temperature should be kept limited and uniform in both time and space, avoiding thermal stresses and hot-spots. For that purpose it is important that the flow of cooling air is distributed uniformly, and that flow separation and recirculation are minimized. Improvements of the air flow properties also lead to an improvement of the overall efficiency of the machine. A significant part of the windage losses occurs at the entrance of the stator ventilation channels, where the air flow turns abruptly from tangential to radial. The present work focuses exclusively on the air flow inside a generator model, and in particular on the flow inside the stator channels. The generator model design of the present work is based on a real generator that was previously studied. The model is manufactured taking into consideration the needs of both the experimental and numerical methodologies. Computational Fluid Dynamics (CFD) results have been used in the process of designing the experimental setup. The rotor and stator are manufactured using rapid-prototyping and plexi-glass, yielding a high geometrical accuracy, and optical experimental access. A special inlet section is designed for accurate air flow rate and inlet velocity profile measurements. The experimental measurements include Particle Image Velocimetry (PIV) and total pressure measurements inside the generator. The CFD simulations are performed based on the OpenFOAM CFD toolbox, and the steady-state frozen rotor approach. Specific studies are performed, on the effect of adding "pick-up" to spacers, and the effects of the

Low eddy loss axial hybrid magnetic bearing with gimballing control ability for momentum flywheel

International Nuclear Information System (INIS)

Tang, Jiqiang; Sun, Jinji; Fang, Jiancheng; Shuzhi Sam, Ge

2013-01-01

For a magnetically suspended momentum flywheel (MSMF), the spinning rotor can be tilted by a pair of the presented axial hybrid magnetic bearing (AHMB) with eight poles and rotates around the radial axes to generate a large torque to maneuver the spacecraft. To improve the control performance and gimballing control ability of the AHMB, characteristics such as magnetic suspension force, angular stiffness and tilting momentum are researched. These segmented stator poles cause the magnetic density in the thrust rotor plate to be uneven unavoidably and the rotational loss is large at high speed, but we optimized the stator poles configuration and caused the thrust rotor plate formed by bulk DT4C and laminated material to make the magnetic density in the thrust rotor plate change less and be smoother. Laminated material such as 1J50 film with a thickness of 0.1 mm can make the variation of the magnetic density in DT4C become very small and the eddy loss of it be negligible, but the stress produced in the “O” shape stacks by reeling has a bad effect on its power loss. Nanocrystalline can reduce eddy losses and is not affected by the reeling process. Based on the AHBM consisting of the stator with eight improved poles and the presented thrust rotor plate with DT4 and nanocrystalline, the rotational loss of 5-DOF magnetically suspended momentum flywheel with angular momentum of 15 N m s at 5000 rpm has reduced from 23.4 W to 3.2 W, which proved that this AHMB has low eddy loss for the gimballing control ability. - Highlights: ► Control methods of rotor driven by AHMBs and their characteristics are researched. ► Optimized stator and rotor of AHMB reduce its eddy losses greatly. ► Presented the factors affecting the eddy losses of AHMBs. ► The good performances of AHMB with low eddy loss are proved by experiments.

Single-current-sensor-based active front-end-converter-fed four ...

Indian Academy of Sciences (India)

Joseph Kiran Banda

Keywords. Field-oriented control; vector control of induction motor; active front end converter; power factor correction .... sinusoidal three-phase input currents applied to the stator. ... with necessary feed-forward terms are employed to control.

Induced Voltage Self-Excitation for a Switched-Reluctance Generator. Experimental Verification of Concept

National Research Council Canada - National Science Library

Lipo, Thomas

2000-01-01

.... One means to excite the machine in a "self-starting" mode is to attach permanent magnets to the machine stator, so that rotor rotation will cause the magnet's field to induce electric current within...

State variable participation in the limit cycle of induction motor

Indian Academy of Sciences (India)

2National Institute of Technical Teachers' Training and Research, Kolkata 700 106, India. ∗ ... nonsymmetrical two stator windings named as the main winding and the auxiliary wind- ... These qualitative changes in the system's dynamics.

Cutting-in control of the variable speed constant frequency wind power generator based on internal model controller

Energy Technology Data Exchange (ETDEWEB)

Guo Jindong; Xu Honghua; Zhao Dongli [Inst. of Electrical Engineering, CAS, BJ (China)

2008-07-01

The no-impact-current cutting-in-network control is the key of variable speed constant frequency (VSCF) wind power control system. Based on the stator flux linkage oriented control theory of doubly fed induction generator (DFIG), the field-oriented vector control technique and the internal model controller (IMC) are transplanted into the voltage control of DFIG and a novel cutting-in control strategy is obtained. The strategy does not need the exact inductor generator model, and has perfect performance without overshoot. The structure of the controller is simple, and the only parameter to be adjusted is directly related to system performance, so the strategy is easy to realize. Finally the strategy is studied by simulation using Matlab, the results of the simulation show that the control strategy can effectively control the stator voltage. (orig.)

Super-twisting sliding mode direct torque contol of induction machine drives

DEFF Research Database (Denmark)

Lascu, Cristian; Blaabjerg, Frede

2014-01-01

This paper presents a new super-twisting sliding modes direct torque and flux controller (STSM-DTC) for induction motor (IM) drives. The STSM is a second-order (type two) variable-structure control which operates without high-frequency chattering. The proposed STSM scheme is a torque and stator...... flux magnitude controller implemented in the stator flux reference frame, and it does not employ current controllers as in conventional vector control. This controller contains a design parameter that allows the designer to balance its operation between a linear PI-like behavior and a constant......-DTC control, design and implementation details, and relevant experimental results for a sensorless IM drive. The scheme is compared to a second-order sliding mode controller and a linear PI controller. A robustness assessment against the PI controller is also included....

A Comprehensive Review of Permanent Magnet Transverse Flux Machines for Direct Drive Applications

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Husain, Tausif [University of Akron; Hasan, Iftekhar [University of Akron; Sozer, Yilmaz [University of Akron; Husain, Iqbal [North Carolina State University

2017-11-07

The use of direct drive machines in renewable and industrial applications are increasing at a rapid rate. Transverse flux machines (TFM) are ideally suited for direct drive applications due to their high torque density. In this paper, a comprehensive review of the permanent magnet (PM) TFMs for direct drive applications is presented. The paper introduces TFMs and their operating principle and then reviews the different type of TFMs proposed in the literature. The TFMs are categorized according to the number of stator sides, types of stator cores and magnet arrangement in the rotor. The review covers different design topologies, materials used for manufacturing, structural and thermal analysis, modeling and design optimization and cogging torque minimization in TFMs. The paper also reviews various applications and comparisons for TFMs that have been presented in the literature.

Eigenvector/eigenvalue analysis of a 3D current referential fault detection and diagnosis of an induction motor

International Nuclear Information System (INIS)

Pires, V. Fernao; Martins, J.F.; Pires, A.J.

2010-01-01

In this paper an integrated approach for on-line induction motor fault detection and diagnosis is presented. The need to insure a continuous and safety operation for induction motors involves preventive maintenance procedures combined with fault diagnosis techniques. The proposed approach uses an automatic three step algorithm. Firstly, the induction motor stator currents are measured which will give typical patterns that can be used to identify the fault. Secondly, the eigenvectors/eigenvalues of the 3D current referential are computed. Finally the proposed algorithm will discern if the motor is healthy or not and report the extent of the fault. Furthermore this algorithm is able to identify distinct faults (stator winding faults or broken bars). The proposed approach was experimentally implemented and its performance verified on various types of working conditions.

Broken Bar Fault Detection in IM Operating Under No-Load Condition

Directory of Open Access Journals (Sweden)

RELJIC, D.

2016-11-01

Full Text Available This paper presents a novel method for broken rotor bar detection in a squirrel-cage induction motor (IM. The proposed method applies a single-phase AC voltage as a test signal on motor terminals, resulting in a stator backward-rotating magnetic field. The field ultimately causes additional current components in the stator windings whose magnitudes depend on the broken bar fault severity, even if the motor is unloaded. This allows robust broken bar fault detection based only on standard motor current signature analysis (MCSA technique. The proposed fault detection method is at first verified via simulations, using an IM model based on finite element analysis (FEA and multiple coupled circuit approach (MCCA. The subsequent experimental investigations have shown good agreement with both theoretical predictions and simulation results.

High performance fuzzy sliding mode control of DFIG supplied by seven level NPC inverter

Directory of Open Access Journals (Sweden)

Mohamed BENKAHLA

2017-09-01

Full Text Available This article presents the powers control of a variable speed wind turbine (WT based on a doubly fed induction generator (DFIG because of their advantages in terms of economy and control. The considered system consists of a double fed induction generator whose stator is connected directly to the network and its rotor is supplied by seven-level inverter with structure NPC are well used to minimize the harmonics absorbed by the DFIG. In order to control the power flowing between the stator of the DFIG and the grid. Have been studied and compared two types of controllers : Sliding Mode Control (SMC and Fuzzy SMC (FSMC. Their respective performances are compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations.

A New Torque Control System of Permanent Magnet Synchronous Motor

Directory of Open Access Journals (Sweden)

Evstratov Andrey

2017-01-01

Full Text Available The article describes a new approach to control of permanent magnet synchronous motor drive based on the analysis of the electromechanical transformation. The proposed control system provides quick response and low ripple of the motor torque and flux. To synthesis this control system, the authors put the electromagnetic torque and the modulus of stator flux vector as controlled values and use the Lyapunov’s second method. In addition, the stator voltage constriction and ability of low-pass filtration are taken into account. The investigation of the proposed control system has carried out with the simulation and the experimental research which have confirmed that the proposed control system correspond to all above-mentioned control tasks and the permanent magnet synchronous motor controlled under this system may be recommended to use in robotics.

Approach to Computer Implementation of Mathematical Model of 3-Phase Induction Motor

Science.gov (United States)

Pustovetov, M. Yu

2018-03-01

This article discusses the development of the computer model of an induction motor based on the mathematical model in a three-phase stator reference frame. It uses an approach that allows combining during preparation of the computer model dual methods: means of visual programming circuitry (in the form of electrical schematics) and logical one (in the form of block diagrams). The approach enables easy integration of the model of an induction motor as part of more complex models of electrical complexes and systems. The developed computer model gives the user access to the beginning and the end of a winding of each of the three phases of the stator and rotor. This property is particularly important when considering the asymmetric modes of operation or when powered by the special circuitry of semiconductor converters.

Simplified Hybrid-Secondary Uncluttered Machine And Method

Science.gov (United States)

Hsu, John S [Oak Ridge, TN

2005-05-10

An electric machine (40, 40') has a stator (43) and a rotor (46) and a primary air gap (48) has secondary coils (47c, 47d) separated from the rotor (46) by a secondary air gap (49) so as to induce a slip current in the secondary coils (47c, 47d). The rotor (46, 76) has magnetic brushes (A, B, C, D) or wires (80) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments. A method of providing a slip energy controller is also disclosed.

Perspectives of application of synthetic diamonds in polyurethane compositions for development of new high thermal conductivity system of isolation of powerful turbogenerators

International Nuclear Information System (INIS)

Kensits'kij, O.G.; Vigovs'kij, O.V.; Khvalyin, D.Yi.

2017-01-01

Reviewed and analyzed components of modern high-voltage insulation of electrical machines. The expediency of increasing of heat-conducting properties of the system of isolation of stator winding of powerful turbogenerators is justified. The main ways of improving heat transfer in the insulation system the stator windings of the turbogenerators are presented and analyzed. Perspectives of application of composite material based on polyurethane with additives of synthetic diamonds for development of new high thermal conductivity system of isolation of powerful electrical machines are analyzed. The technology by which was created the prototype of the insulating material with the application of diamond powder in a polyurethane composition is described. Executed laboratory experimental researches of the electrophysical parameters of the sample developed insulating material. That showed the perspective of this direction of perfection of isolation.

Detection of Partial Demagnetization Fault in PMSMs Operating under Nonstationary Conditions

DEFF Research Database (Denmark)

Wang, Chao; Delgado Prieto, Miguel; Romeral, Luis

2016-01-01

Demagnetization fault detection of in-service Permanent Magnet Synchronous Machines (PMSMs) is a challenging task because most PMSMs operate under nonstationary circumstances in industrial applications. A novel approach based on tracking characteristic orders of stator current using Vold-Kalman F......Demagnetization fault detection of in-service Permanent Magnet Synchronous Machines (PMSMs) is a challenging task because most PMSMs operate under nonstationary circumstances in industrial applications. A novel approach based on tracking characteristic orders of stator current using Vold......-Kalman Filter is proposed to detect the partial demagnetization fault in PMSMs running at nonstationary conditions. Amplitude of envelope of the fault characteristic orders is used as fault indictor. Experimental results verify the superiority of the proposed method on partial demagnetization online fault...... detection of PMSMs under various speed and load conditions....

An improved iron loss estimation for permanent magnet brushless machines

CERN Document Server

Fang, D

1999-01-01

This paper presents an improved approach for predicting iron losses in permanent magnet brushless machines. The new approach is based on the fundamental concept that eddy current losses are proportional to the square of the time rate of change of flux density. Expressions are derived for predicting hysteresis and eddy current losses in the stator teeth and yoke. The so-called anomalous or excess losses, caused by the induced eddy current concentration around moving magnetic domain walls and neglected in the conventional core loss calculation, are also included in the proposed approach. In addition, the model is also capable of accounting for the stator skewing, if present. The core losses obtained from the proposed approach are compared with those measured on an existing PM motor at several operating speeds, showing very good agreement. (14 refs).

Aerodynamic and Performance Behavior of a Three-Stage High Efficiency Turbine at Design and Off-Design Operating Points

Directory of Open Access Journals (Sweden)

M. T. Schobeiri

2004-01-01

Full Text Available This article deals with the aerodynamic and performance behavior of a three-stage high pressure research turbine with 3-D curved blades at its design and off-design operating points. The research turbine configuration incorporates six rows beginning with a stator row. Interstage aerodynamic measurements were performed at three stations, namely downstream of the first rotor row, the second stator row, and the second rotor row. Interstage radial and circumferential traversing presented a detailed flow picture of the middle stage. Performance measurements were carried out within a rotational speed range of 75% to 116% of the design speed. The experimental investigations have been carried out on the recently established multi-stage turbine research facility at the Turbomachinery Performance and Flow Research Laboratory, TPFL, of Texas A&M University.

3D numerical analysis and optimization of aerodynamic performance of turbine blade

International Nuclear Information System (INIS)

Wang Dingbiao; Xie Wen; Zhou Junjie

2010-01-01

To reduce the stator profile loss and improve the efficiency of the industrial steam turbine, a numerical analysis and optimization of the data for the steam turbine stator blade are conducted by the NUMECA,a CFD software. The result shows that, compared with the original blade, the 'after loading' blade is with the best static pressure coefficient distribution, and effectively postpones the transition point position, reduces the radial pressure gradient of suction surface, and cut down the secondary flow loss effectively. The total pressure losses of the 'after loading' blade is 1.03%, which is the least, and the single-stage efficiency is 94.462%, which is the maximum and increases 14.33%. Thus, the aerodynamic performance of stage is improved obviously, the profile loss decreases through using the 'after loading' blade. (authors)

A spiral motion piezoelectric micromotor for autofocus and auto zoom in a medical endoscope

Science.gov (United States)

Chen, Xi; Chen, Zhijiang; Li, Xiaotian; Shan, Liang; Sun, Wanchen; Wang, Xiguang; Xie, Tianyu; Dong, Shuxiang

2016-02-01

We report a hollow type piezoelectric micromotor made of a PZT ceramic/metal composite cylinder with sizes of only 3.6 mm in diameter and 3.0 mm in length aiming at medical endoscope application. The hollow piezoelectric stator of the micromotor, acting as a nut, can excite E02-mode traveling wave along its circumferential direction, and a hollow rotor with a fine lens inside, acting as a screw, is driven to produce a spiral motion along its axis direction inside the hollow stator via the traveling wave. The features of the developed micromotors are its hollow, fine structure and submicrometer step resolution, ensuring that the optical path passes in a narrow and limited space and that the optical focal length is tuned precisely inside the endoscope, which is meaningful in medical diagnosis.

Algorithm for Identification Electromagnetic Parameters of an Induction Motor When Running on a Three-Phase Power Plant

Directory of Open Access Journals (Sweden)

D. S. Odnolko

2013-01-01

Full Text Available Synthesized algorithm for electromagnetic rotor time constant, active resistance and equivalent leakage inductance of stator induction motor for free rotating rotor. The problem is solved for induction motor model in the stationary stator frame α-β. The algorithm is based on the use of recursive least squares method, which ensures high accuracy of the parameter estimates for the minimum time. The observer does not assume prior information about the technical data machine and individual parameters of its equivalent circuit. Results of simulation demonstrated how effective of the proposed method of identification. The flexible structure of the algorithm allows it to be used for preliminary identification of an induction motor, and in the process operative work induction motor in the frequency-controlled electric drive with vector control.

Aerodynamic Modelling and Optimization of Axial Fans

DEFF Research Database (Denmark)

Sørensen, Dan Nørtoft

A numerically efficient mathematical model for the aerodynamics oflow speed axial fans of the arbitrary vortex flow type has been developed.The model is based on a blade-element principle, whereby therotor is divided into a number of annular streamtubes.For each of these streamtubes relations......-Raphson method, andsolutions converged to machine accuracy are found at small computing costs.The model has been validated against published measurementson various fan configurations,comprising two rotor-only fan stages, a counter-rotatingfan unit and a stator-rotor-stator stage.Comparisons of local...... and integrated propertiesshow that the computed results agree well with the measurements.Integrating a rotor-only version of the aerodynamic modelwith an algorithm for numerical designoptimization, enables the finding of an optimum fan rotor.The angular velocity of the rotor, the hub radius and the spanwise...

Total cross sections for nu$_{mu}$ and n$\\overline{u}_{mu}$ charged-current interactions between 20 and 200 GeV

CERN Document Server

Bosetti, Peter C; Fritze, P; Grässler, Herbert; Hasert, F J; Schulte, R; Böckmann, Klaus; Kokott, T P; Nellen, B; Wünsch, B; Cundy, Donald C; Grant, A; Hulth, P O; Klein, H; Morrison, Douglas Robert Ogston; Pagiola, E; Pape, L; Peyrou, Charles; Scott, W G; Wachsmuth, H W; Simopoulou, Errietta; Vayaki, Anna; Barnham, Keith W J; Butterworth, Ian; Iaselli, Giuseppe; Miller, D B; Mobayyen, M; Penfold, C; Petrides, A; Powell, K J; Albajar, C; Perkins, Donald Hill; Radojicic, D; Saitta, B; Bolognese, T; Tallini, Bruno; Velasco, J; Vignaud, D

1982-01-01

Exposures of the Ne/H/sub 2/ filled Big European Bubble Chamber (BEBC) to a dichromatic neutrino (antineutrino) beam produced by 400 GeV protons of the CERN SPS yielded approximately 3100 events with a negative, and approximately 1100 with a positive, muon. The neutrino flux is determined from the muon flux in the shielding. Assuming a linear energy dependence of the cross section, the values sigma /E between 20 and 200 GeV are found to be 0.657+or-0.012 (stat.)+or-0.027 (syst.) and 0.309+or-0.009 (stat.)+or-0.013 (syst.) cm/sup 2/ (GeV nucleon)/sup -1/, for neutrinos and antineutrinos, respectively. The scaling variable q/sup 2//E decreases significantly with increasing energy both for neutrinos and antineutrinos.

Self-commissioning of permanent magnet synchronous machine drives using hybrid approach

DEFF Research Database (Denmark)

Basar, Mehmet Sertug

2016-01-01

Self-commissioning of permanent-magnet (PM) synchronous machines (PMSMs) is of prime importance in an industrial drive system because control performance and system stability depend heavily on the accurate machine parameter information. This article focuses on a combination of offline and online...... parameter estimation for a non-salient pole PMSM which eliminates the need for any prior knowledge on machine parameters. Stator resistance and inductance are first identified at standstill utilising fundamental and high-frequency excitation signals, respectively. A novel method has been developed...... and employed for inductance estimation. Then, stator resistance, inductance and PM flux are updated online using a recursive least-squares (RLS) algorithm. The proposed controllers are designed using MATLAB/Simulink® and implemented on d-Space® real-time system incorporating a commercially available PMSM drive....