• 한국전기전자재료학회논문지
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• 제21권12호
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• pp.1124-1129
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• 2008

The object of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We made a comparative analysis on Insulation Resistance (IR), Dielectric Absorption Ratio (DAR), and Polarization Index (PI) of the motor stators. The experiment was carried out according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Test voltage of 500 V was applied between a phase and the enclosure. The IR and the DAR of used motors were lower than those of new ones. The DAR and the PI were $0.92{\sim}1.02$ and $0.74{\sim}1.1$, respectively and the result did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of the traction motor stator by the comparative analysis of short-time insulation resistance changes, DAR and PI.

• Journal of Welding and Joining
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• 제4권3호
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• pp.58-71
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• 1986

Mechanical and corrosion property of duplex stainless steel weldments made by the GTAW and SMAW process were studied. Fracture toughness, general and local corrosion resistance of GTAW and SMAW weldments were evaluated in terms of Charpy V notch impact test, anodic polarization diagram, pitting corrosion rate, respectively. SMA weld metal showed much lower impact toughness and higher ductile-brittle transition temperature than GTA weld metal. Fractographic and EDX analysis on fracture surface of SMA weld metal demonstrated the existence of (Si, Ti), oxide in large amounts. Potentiodynamic anodic polarization diagram of GMA weld metal showed much lower passive current density than SMA weld metal in 4% $H_2/SO_4$ solution. And pitting corrosion rate test showed the same tendency. Relating the microstructure, chemistry and property, it can be concluded that GTA weld metal gives better toughness due to lower oxygen content, i.e. lower inclusion content, and better corrosion resistance due to higher Pitting Index(PI) than SMA weld metal.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1374-1376
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• 2000

In this paper, sample coils for stator form-wound winding of traction motor were tested by the accelerative thermal degradation, which composed of heat, vibration, moisture and overvoltage applying. Reliability and expected life were evaluated on the insulation system for 200 class traction motor. After aging of 10 cycles, insulation resistance and PI properties were investigated as diagnosis tests in the range of $20{\sim}160^{\circ}C$. Analysis of polarization properties was performed on the base of do current-time change.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.219-224
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• 2008

The purpose of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We carried out a comparative analysis on Insulation Resistance (IR) and Polarization Index (PI) of motor stators according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Maximum test voltage which is applied to between a phase and enclosure was set at 500 V. The IRs of the used motors were lower than those of the new ones. The PIs of the used motor were ranges from 0.74 to 1.1 and did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of motor stators by comparative analysis of the IR and the PI.

• 전력전자학회논문지
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• 제8권3호
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• pp.247-252
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• 2003

전동기 절연열화와 파괴는 전동기에 가해지는 스트레스에 영향을 받는다. 즉 절연물의 수명은 주어지는 스트레스의 심한 정도에 따라서 좌우된다. 전동차용 견인전동기에서도 과도서지에 의한 전기적인 열화를 검토하는 것은 매우 중요한 요소이다. 본 논문에서는 인버터에서 발생되는 과도서지에 의한 고정자 코일의 절연특성을 고찰해 보았다. 전동기의 절연상태, 열화진전도, 열화발생 범위 등을 측정하는 유용한 비파괴시험 방법에는 여러 가지가 이용되고 있다. 누설전류, 유전손실(tan$\delta$), 정전용량, 성극지수(PI), 부분방전 등의 방법들을 통하여 고정자 코일의 절연상태를 분석하였다. 이러한 진단 방법들은 전동차의 견인전동기에 대한 열화상태와 수명예측에 유용한 방법이 될 것으로 여겨진다.

• 전기학회논문지
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• 제57권10호
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• pp.1818-1821
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• 2008

Several off-line diagnostic tests which include the insulation resistance(IR), polarization index(PI), low-voltage AC, and recurrent surge oscillograph(RSO) tests were performed to assess the condition of generator rotor windings. The low-voltage AC and the RSO tests were performed on the gas turbine generator rotor winding to detect shorted turns. Before intentionally applying artificial shorted faults, it was confirmed by the low voltage AC and the RSO tests that the winding was in sound condition. For simulated shorted rotor winding turns, the RSO test detected the fault in the winding. The RSO test was capable of identifying the number and pole location of the shorted turns for a number of simulated shorted coils.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.420-422
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• 2003

Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper Presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging,. and the rate of which aging is taking pace. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss($tan{\delta}$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and Predict the life of the traction motor in EMU.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.623-627
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• 2003

Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss($tan{\delta}$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and predict the life of the traction motor in EMU.

• 대한전기학회논문지
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• 제45권4호
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• pp.553-557
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• 1996

Heat cycle aging of insulating materials in large generator stator winding has been investigated using both on-line and off-line test methods. On this study, principally, off-line test against actual generator in service was carried out to acquire information about polarization index(PI) and dissipation factor, dissipation factor tip-up, maximum partial discharge for the purpose of remnant breakdown voltage and life assessment. It was found from the tests that both dissipation factor and maximum partial discharge decreased with the increase of operating hours and starting numbers. It was found from off-line tests that the remnant breakdown voltage had a strong relationship with both dissipation factor and maximum partial discharge the remnant breakdown voltage as a results of both operating hours and starting number and the nondestructive tests were proposed as parameters which can predict the remnant lifetime of insulating materials in large generator stator windings. (author). 8 refs., 8 figs., 2 tabs.