• Title/Summary/Keyword: Stator winding

Search Result 425, Processing Time 0.028 seconds

Characteristics of Insulation Diagnosis and Failure in 6.6 kV Motor Stator Windings (6.6 kV 전동기 고정자 권선의 절연진단과 절연파괴 특성)

  • Kim, Hee-Dong;Kong, Tae-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.25 no.4
    • /
    • pp.309-314
    • /
    • 2012
  • To assess the condition of stator insulation, nondestructive and overpotential tests were performed on four high voltage motors. The stator windings under these tests have nominal ratings of 6.6 kV. After completing nondestructive tests, the AC overvoltage applied to the stator windings was gradually increasing until insulation failure in order to obtain the breakdown voltage. No. 1, No. 2, No. 3 and No. 4 of 6.6 kV motors failed near rated voltage of 18.4 kV, 19.8 kV, 19.7 kV and 21.7 kV, respectively. The breakdown voltage of four motors was higher that expected for good quality coils(14.2 kV) in 6.6 kV motors. Almost all of failures were located in a line-end coil at the exit from the core slot. The breakdown voltages and the types of defects showed strong relation to the stator insulation tests such as in the case of AC current, dissipation factor(tanδ) and partial discharge magnitude.

A Study on the Change of Dynamic Characteristics of Stator Windings due to Generator Operation (발전기 운전에 따른 고정자 권선의 진동 특성 변화)

  • Kim, Hee-Soo;Bae, Yong-Chae;Lee, Doo-Young;Kim, Yeon-Whan;Lee, Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.1029-1033
    • /
    • 2006
  • During operation of generator, the excitation force with 120Hz always exist irrespective of No. of poles. Therefore the vibration is generated in the stator end windings and the micro-crack is grown up inside the bars. After all, coolant water is leaked outside the bars or the stator is moved and is worn out. What is more, one bar is touched with another bar so a short circuit may frequently happen in operation. In order to prevent it from occurring, the evaluation of mechanical integrity for generator stator windings is carried out periodically during overhaul period. This help troublesome end windings to complement with insulation material and to change vibration characteristics. In this paper, the evaluation of mechanical integrity for generator stator windings is described and the change of vibration characteristics is analysed.

  • PDF

Analysis of Insulation Aging in High Voltage Motor Stator Windings (고압전동기 고정자 권선의 절연열화 분석)

  • Kim, Hee-Dong;Kong, Tae-Sik;Lee, Young-Jun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2006.06a
    • /
    • pp.200-203
    • /
    • 2006
  • Prior to destructive testing, diagnostic tests were performed in eight high voltage motors. Diagnostic tests included polarization index, ac current, dissipation factor(tanδ) and partial discharge magnitude. The rewind of motor stator insulation at rated voltage is assessed by the results of these tests. After completing the diagnostic tests, the stator windings of motors were subjected to gradually increasing ac voltage, until the insulation punctured. No. 1 motor failed near rated voltage of 12.96 kV. The breakdown voltage of No. 4 motor was 6.99 kV which is lower that expected for good quality coils in 6.6 kV class motors. The failure was located in a line-end coil at the exit from the core slot. These two motors began operation in 1994. While testing No. 7 motor, flashover occurred between the stator winding and the stator frame at 15 kV. The relationship between the diagnostic test and the drop in insulation breakdown voltage was analyzed.

  • PDF

Development and Performance Test of a l00hp HTS Motor

  • Sohn, M.H.;Baik, S.K.;Lee, E.Y.;Kwon, Y.K.;Yun, M.S.;Moon, T.S.;Park, H.J.;Kim, Y.C.;Ryu, K.S.
    • Progress in Superconductivity and Cryogenics
    • /
    • v.6 no.4
    • /
    • pp.27-31
    • /
    • 2004
  • This paper describes the development and fabrication of a high temperature superconducting motor which consists of HTS rotor and air-core stator. The machine was designed for the rated power of 100hp at 1800 rpm. The HTS field windings are composed of the double-pancake coils wound with AMSC's SUS-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. Characteristic parameters such as reactances, inductances, and time constants were determined to obtain a consistent overview of the machine operation properties. This motor has met all design parameters by demonstrating HTS field winding, cryogenic refrigeration systems and an air-core armature winding cooled with air. The HTS field winding could be cooled down below 30K. No-load test of open-circuit characteristics(OCC) and short-circuit characteristics(SCC) and load test with resistive load bank were conducted in generator mode. Maximum operating current of field winding at 30K was 120A. From OCC and SCC test results synchronous inductance and synchronous reactance were 2.4mH, 0.49pu, respectively. Efficiency of this HTS machine was 93.3% in full load(100hp) test. This paper will present design, construction, and basic experimental test results of the 100hp HTS machine.

A Study on Multi-Physics Analysis of High-Resolution Winding Type Resolver and Rotary Transformer (고정밀 권선형 레졸버의 변압부 및 레졸버 연동해석 연구)

  • Shin, Young-Chul;Kim, Ki-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.5
    • /
    • pp.146-152
    • /
    • 2016
  • This paper describes a multi-physics analysis of a high resolution winding type resolver and rotary transformer using FEM (Finite Element Method). The rotary transformer boosts the input voltage to a high voltage which can be input into the rotor windings of the resolver. Through multi-physics models of the transformer and resolver, the characteristics of the output signals for the resolver system with high resolution can be derived. Moreover, the circuit model of the interface part between the transformer and resolver should be considered, because of the calculation of the input current to the resolver. The winding type resolver is composed of 32x and 1x stator windings for high resolution. Then, the output signals of the stator windings, which make sinusoidal SIN and COS waves with a 90 phase difference, are verified.

Distribution Characteristics of Irregular Voltage in Stator Windings of IGBT PWM Inverter-Fed Induction Motors (IGBT PWM 인버터 구동 유도전동기 고정자 권선에서의 과도전압 분포특성)

  • 황돈하;김용주;이인우;배성우;김동희;노체균
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.8 no.4
    • /
    • pp.351-358
    • /
    • 2003
  • This paper describes distribution characteristics of switching surge voltage in stator windings of induction motor driven by IGBT PWM inverter. To analyze the voltage distribution between the turns and coils of stator winding, equivalent circuit model of induction motor including cable was proposed and high frequency parameter is computed by using finite-element method (FEM). From the electro-magnetic transient program (EMTP) simulation of the whole system for induction motor, feeder cable, and PWM inverter, the variable effect on rising time of the inverter, cable length, and switching frequency on the voltage distribution is also presented. In order to experiment, an induction motor, 380[V], 50[HP], with taps from one phase are built to consider the voltage distribution so that these results can be helpful when filter was designed to remove high dv/dt.

A study on how to discriminate the polarities of stator windings for 3 phase induction motors by using general purpose multi-testers (멀티테스터를 이용한 3상유도전동기 고정자 권선의 극성 판별법에 관한 연구)

  • Choi, Soon-Man
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.38 no.9
    • /
    • pp.1137-1140
    • /
    • 2014
  • Faulty electric motors onboard vessels with anomalies in windings or poor insulation are usually repaired at land based workshops and reinstalled in place by crew hands after receiving the repaired motors. Especially for 3 phase induction motors which need Y-δ starters with 6 lead wires, it would happen that the polarities of stator windings cannot be well distinguished if the original tags of these wires are erased or not visible clearly, resulting in subsequent damage to the repaired motor due to extreme current flow when the power is given to the motor the stator windings of which are wrongly connected in the polarity. This study proposes an easy way to make correct connection in winding polarities without failures based on the electro-magnetically induced voltages on windings when a slight DC current is supplied to a winding coil by using an analog multi-tester. The proposed method is applied to actual motors and delves into the applicability for polarity discrimination through a few measurements onboard vessels.

Designs of 10 MW Air-core and Iron-core HTS Wind Power Generators

  • Sung, Hae-Jin;Park, Minwon;Yu, In-Keun
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.2
    • /
    • pp.545-550
    • /
    • 2015
  • High Temperature Superconducting (HTS) synchronous generators can be designed with either an air-core type or iron-core type. The air-core type has higher efficiency under rated rotating speed and load than the iron-core type because of the iron losses which may produce much heat. However, the total length of HTS wire in the air-core type is longer than the iron-core type because the generated magnetic flux density of the air-core type is low. This paper deals with designs of 10 MW air-core and iron-core HTS wind power generators for wind turbines. Fully air-core, partially iron-core, and fully iron-core HTS generators are designed, and various stator winding methods in the three HTS generators are also considered, such as short-pitch concentrated winding, full-pitch concentrated winding, short-pitch distributed winding, and full-pitch distributed winding. These HTS generators are analyzed using a 3D finite elements method program. The analysis results of the HTS generators are discussed in detail, and the results will be effectively utilized for large-scale wind power generation systems.

A Low Cogging Force Permanent Magnet Linear Motor Having 3 Phase 9 Pole 10 Slot Structure (코깅력이 저감된 3상 9극 10슬롯 구조의 영구자석 선형 전동기)

  • Youn, Sung-Whan;Lee, Jong-Jin;Koh, Chang-Seop
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.55 no.11
    • /
    • pp.547-554
    • /
    • 2006
  • The detent force of a permanent magnet linear motor(PMLM) consists of the end force and cogging force, and should be reduced for high precision purpose applications. The cogging force comes from the electromagnetic interaction between the permanent magnets and interior teeth(or the slots) of the stator, and of which the magnitude depends on the ratio of the numbers of the armature and permanent magnet poles as well as the geometrical shape of the permanent magnet and armature pole. In order to reduce the cogging force of a PMLM, this paper proposes a new configuration which has 9 permanent magnet poles and 10 armature winding slots. By theoretical investigation of the principle of cogging force generation and simulating using finite element method, the proposed PMLM configuration is proven to give much less cogging force than the conventional configuration which has 8 permanent magnet poles and 12 armature winding slots. A proper winding algorithm, modified (A, A, A) winding method, for the proposed configuration is also suggested when the proposed PMLM is operating as a 3 phase synchronous machine. A theoretical and numerical calculation shows that the proposed configuration makes slightly bigger back-emf and thrust force under same exciting current and total number of winding turns condition.

Assessment of Insulation Aging in 6.6 kV Class High Voltage Motor Stator Windings (6.6 kV급 고압전동기 고정자 권선의 절연열화 평가)

  • Kim, Hee-Dong;Kim, Byong-Han
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.19 no.11
    • /
    • pp.1067-1071
    • /
    • 2006
  • Prior to destructive testing, diagnostic tests were performed in ten high voltage motors. Diagnostic tests included polarization infer, ac current, dissipation factor(tanδ) and partial discharge magnitude. The rewind of motet slater insulation at rated voltage is assessed by the results of these tests. After completing the diagnostic tests, the stator windings of motors were subjected to gradually increasing ac voltage, until the insulation punctured. No. 8 motor failed near rated voltage of 19.0 kV. The breakdown voltage of No. 4 motet was 7.0 kV which is lower that expected for good quality coils in 6.6 kV class motors. The failure was located in a line-end coil at the exit from the core slot. These two motors began operation in 1994. While testing No. 7 motor, flashover occurred between the stator winding and the stator frame at 15 kV. The relationship between the diagnostic test and the drop in insulation breakdown voltage was analyzed.