• Title/Summary/Keyword: Stator Slots

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Analysis on Noise of Automotive Alternator Considering the Number of Stator Slots (승용차용 교류발전기의 고정자 슬롯 수가 소음에 미치는 영향 분석)

  • Song, Jin-Seo;Kim, Gwang-Jun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1 s.173
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    • pp.126-133
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    • 2000
  • Noise of automotive alternators can be classified into mechanical noise, aerodynamic noise and electro-magnetic noise. which is the same as for electric motors. Previous studies show that the elect ro-magnetic noise takes a maw peak at the rotating frequency multiplied by the number of stator slots. It has not been proved clearly so far, however, that the major peak is wholely due to the stator slots. On the contrary it is well known that noise of motors. which has a mechanism similar to the alternator except that the number of stator slots in automotive alternators is in gene\integer multiple of that of rotor segments, is closely related to the number of rotor slots. Therefore, the statement that only the stator slots is the source of the major peak in the noise spectrum of alternators is suspicious although not easy, to show theoretically, that the statement is incorrect. In this paper. effects of the stator slots on the noise in an automotive alternator are experimentally investigated by intentionally modifying the number of stator slots in such a way that the number of the states is not an integer multiples of the rotor slots. It is shown that both the stator slots are not so much influential as the rotor slots and claimed that the major peak in the noise spectrum of conventional alternators is due to superposition of a component caused by the stator and a higher harmonic component caused by the rotor

A Study on the Skewed Stator Slots and Skewed Rotor Magnet Segments of BLDCM (BLDCM에서의 스쿠슬롯과 스큐자극에 대한 고찰)

  • 김광헌;심동준;원종수
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.7
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    • pp.643-655
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    • 1991
  • The analysis method on air gap permeance distribution, air gap MMF distribution, air gap flux density distribution, cogging torque and BEMF about the skewed stator slots or the skewed rotor magnet segments for BLDCM, respectively, is studied as a function of the skew ratio. The proposed method describes the differences between the skewed stator slots and teh skewed rotor magnet segments for the air gap permeance distribution, air gap MMF distribution and air gap flux density distribution. The reliability of the method is also confirmed by the waveform of the cogging torque and BEMF through experiments. And the result shows that the effects on the cogging torque and BEMF due to the skewed stator slots or the skewed rotor magnet segments are the same. In case of the skewed stator slots, the effects of the variations of the winding resistance and inductance are also studied.

The Protection Method against the Operation under Unbalance Voltage in 3-phase Squirrel-Cage Induction Motor (3상절형유도전동기의 불평형운전에 대한 보호 방안)

  • 이은욱;박윤호
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.33 no.8
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    • pp.281-288
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    • 1984
  • A new method of protecting 3-phase squirrel-cage induction motor aginst burning-out by unbalance operation is proposed. This paper studied various kinds of situations occurred by unbalance operating in 3-phase induction motor, and we provided the search coils in the slots of stator and rotor for the purpose of detecting electrical phenpmena during unbalance operation. Through experiments, we find that search coils in the slots of stator is effective method for protecting the induction motor from unbalance operating.

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A Study On The Stator Slot Shape Design of BLDC Motor (BLDC 모터 고정자 슬롯 형상설계에 관한 연구)

  • Han, Sang-Rog;Lee, Kang-Yeon;Jeong, Byeong-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.5
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    • pp.41-49
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    • 2015
  • In this paper, we studied an optimal design and efficiency improvement of the BLCD motor used in home electronic appliance. The number of stator slots is chosen depending on the rotor poles, phase number, and the winding configuration. In general, a fractional slots/pole design is preferred to minimize cogging torque. To reduce the winding resistance, we reduced the coil length and we improved the coil space factor. We proposed three types of stator slot shape design for the optimal BLDC motor design. One of them, U-type slot shape is a best optimal design, it proved by the simulated and tested. Optimal design of essential parameters aiming at high winding factor are presented to create for a high-quality system implementation. Design analysis is verified by testing and building a prototype motor.

Analysis of Static Characteristics of PMLSM Using Space Harmonic Analysis Considering Slot Structure (공간고조파법을 이용한 영구자석 선형 동기전동기의 슬롯을 고려한 정특성 해석)

  • Im, Gi-Chae;Hong, Jeong-Pyo;Kim, Gyu-Tak
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.4
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    • pp.145-151
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    • 1999
  • This paper presents the characteristic analysis method of PMLSM based on the Space Harmonic Analysis method considering the effect of stator slots. The magnetic field for unslotted primary can be easily calculated by the conventional space harmonic analysis method and the resultant magnetic field including slot effect is obtained using the concept of the virtual Equivalent Magnetizing Current(EMC) on primary core. And the influence of space harmonics in airgap flux density and static thrust due to slots is evaluated. In this paper, the results of the analytical method are compared with not only the experimental ones but ones of FEM to verify the validity of the proposed method.

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Analysis of Slot Leakage Reactance of Submersible Motor with Closed Slots during Starting Transient Operation

  • Bao, Xiaohua;Di, Chong;Fang, Yong
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.135-142
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    • 2016
  • Generally, closed slots are adopted to reduce the water friction loss in both the stator and the rotor of water filling submersible motor due to the special environment of operation. One of the obvious differences between the traditional induction motors and water filling submersible motors is that the submersible motors only need relatively smaller starting torque. This paper aims to analyze the slot leakage reactance of water filling submersible motor during starting transient operation. An improved analytical method which considered the magnetic saturation of the slot bridge and the skin effect of rotor bars is proposed. The slot permeance factor which has a direct impact on the slot leakage reactance is calculated. Then finite element models with different stator slot types are constructed and search coils are introduced to measure the slot flux linkage. Moreover, the starting performances of the models with two typical stator slots are compared and the flux leakage characteristics are obtained. Finally, the results obtained by finite element method are very close to the results obtained by analytical method.

Assessment of Insulation Condition in Operating Large Turbine Generator (운전중인 대형 터빈발전기에서 절연상태 평가)

  • 김희동
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.6
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    • pp.324-329
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    • 2004
  • Six stator slot couplers(SSC) and a flux probe sensor installed on the stator winding slots of large turbine generator. Assessment of insulation condition has been based upon the measurements of partial discharge(PD) of stator windings and shorted-turn of rotor windings in operating large turbine generator. The maximum PD magnitude(Qm), normalized quantify number(NQN), PD pattern and shorted-turn were measured using on-line insulation condition monitoring system. The NQN and Qm of slot PD side in the phase A are indicated the highest value in six SSC sensors. Monitoring system results showed that discharge at conductor surface and internal discharge were detected at the surface of stator winding and in voids of the groundwall insulation. Insulation of stator and rotor windings in large turbine generator was judged to be in good condition.

Radial Force Analysis of a Single-Phase Permanent Split Condenser Induction Motor with skewed slots (사구 슬롯이 있는 콘덴서 구동형 단상 유도 전동기의 Radial force 해석)

  • Chang, Jung-Hwan;Hyun, Dong-Seok
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.241-243
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    • 1996
  • This papar presents an analysing method of radial force densities acting on each stator tooth of an induction motor with skewed slots. Two-dimensional finite element method is used for electromagnetic Held analysis of an induction motor, and skew effects are considered by coupling several disks cut by planes perpendicular to the shaft. Radial force densities as a source of vibration are calculated along the surface elements of each stator tooth and its time harmonics are examined by discrete Fourier decomposition.

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Fabrication of the Windmill Type Ultrasonic Its Characteristics of Torque and Bidirectional Revolution (풍차형 초음파 전동기의 제작과 토크 및 정$\cdot$역회전특성)

  • Kim, Young-Gyun;Kim, Jin-Soo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.3
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    • pp.105-109
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    • 2001
  • In this paper, the windmill type ultrasonic motors with 11.35 mm diameter, 2.87 mm thickness of metal endcap and 1.47 g weight were fabricated. Effects of slots and thickness on torque characteristic in the windmill type ultrasonic motor were investigated, when stator's slots were changed from 4, 6, 8 and thickness 0.15 mm, respectively. Specially designed metal endcaps with windmill shaped cutting can provide longitudinal and torsional displacements simultaneously as the ceramic disk vibrates radically. The windmill type ultrasonic motor has only three components: a stator element with windmill shape slotted metal endcap, a rotor and bearing. Ultrasonic motor stimulated to ultrasonic oscillations by piezoelectrics to drive a rotor via friction contact. The ultrasonic motor fabricated here was the windmill type ultrasonic motor operated by single-phase AC source. Bidirectional revolution using single-phase high frequency for driving the ultrasonic motor was presented.

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Analysis of Voltage Stress in Stator Windings of IGBT PWM Inverter-Fed Induction Motor Systems

  • Hwang Don-Ha;Lee Ki-Chang;Jeon Jeong-Woo;Kim Yong-Joo;Lee In-Woo;Kim Dong-Hee
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.1
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    • pp.43-49
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    • 2005
  • The high rate of voltage rise (dv/dt) in motor terminals caused by high-frequency switching and impedance mismatches between inverter and motor are known as the primary causes of irregular voltage distributions and insulation breakdowns on stator windings in IGBT PWM inverter-driven induction motors. In this paper, voltage distributions in the stator windings of an induction motor driven by an IGBT PWM inverter are studied. To analyze the irregular voltages of stator windings, high frequency parameters are derived from the finite element (FE) analysis of stator slots. An equivalent circuit composed of distributed capacitances, inductance, and resistance is derived from these parameters. This equivalent circuit is then used for simulation in order to predict the voltage distributions among the turns and coils. The effects of various rising times in motor terminal voltages and cable lengths on the stator voltage distribution are also presented. For a comparison with simulations, an induction motor with taps in the stator turns was made and driven by a variable-rising time switching surge generator. The test results are shown.