• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.450-456
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• 2005

In this paper, the effect of adhesion properties of semiconductive-insulating interface layer of silicone rubber on electrical properties was investigated. The modifications produced on the silicone surface by oxygen plasma were accessed using ATR-FTIR, contact angle and Surface Roughness Tester. Adhesion was obtained from T-peel tests of semiconductive layer haying different treatment durations. In addition, ac breakdown test was carried out for elucidating the change of electrical property with duration of plasma treatment. From the results, the treatment in the oxygen plasma produced a noticeable increase in surface energy, which can be mainly ascribed to the creation of O-H and C=O. It is observed that adhesion performance was determined by surface energy and roughness level of silicone surface. It is found that at dielectric strength was increased with improving the adhesion between the semiconductive and insulating interface.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.449-451
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• 1999

When the traction motor for urban transit E.M.U is driven with VVVF controlled inverter, the insulation degradation factors on the 200 Class insulation system of VPI process are analyzed with considering dielectric, mechanical properties, thermal stability, chemical resistivity and compatibility. A new test method of complex accelerating degradation is proposed to evaluate the insulation reliability and the long-term life including harmonic loss and transient surge stress due to PWM inverter drive.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.452-454
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• 1999

In this paper, sample coils for stator form-wound winding of traction motor were made for the accelerative thermal degradation composed of heat, vibration, moisture and overvoltage. In progress of test periods, diagnosis tests such as insulation resistance, dielectric loss and partial discharge were investigated. Reliability and expected life were evaluated on the insulation system for 200 class traction motor considering various environmental stress.

• Proceedings of the KSR Conference
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• 2003.10c
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.93-101
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• 2002

In this study, the stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the C-Class(200$\^{C}$ ) insulation system of traction motors. The complex accelerative degradation was periodically performed during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, the condition diagnosis test such as insulation resistance '||'&'||' polarization index, capacitance '||'&'||' dielectric loss and partial discharge properties were investigated in the temperature range of 20 ∼ 160$\^{C}$. Relationship among condition diagnosis tests was analyzed to find a dominative degradation factor and an insulation state at end-life point.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.1
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• pp.1-4
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• 2003

This paper presents an attempt to develop probabilistic multistress life models to evaluate the lifetime characteristics of epoxy-encapsulated magnet wire with heavy build polyurethane enamel. A set of accelerated life tests were conducted over a wide range of pulsating voltages, temperatures, and frequencies. Samples of fine gauge twisted pairs of the encapsulated magnet wire were tested us-ing a pulse endurance dielectric test system. An electrical-thermal lifetime function was combined with the Weibull distribution of lifetimes. The parameters of the combined Weibull-electrical-thermal model were estimated using maximum likelihood estimation. Likewise, a generalized electrical-thermal-frequency life model was also developed. The parameters of this new model were estimated using multiple linear regression technique. It was found in this paper that lifetime estimates of the two proposed probabilistic multistress life models are good enough. This suggests the suitability of using the general electrical-thermal-frequency model to estimate the lifetime of the encapsulated magnet wire over a wide range of voltages, temperatures and pulsating frequencies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.521-524
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• 1997

TZDB(Time-Zero Dielectric Breakdown)법을 이용하여 CZ법으로 성장된 6인치완 8인치 실리콘 웨이퍼의 미세 결함에 대해 조사하였다. 80$0^{\circ}C$에서 $N_2$분위기로 성장시킨 SiO$_2$를 이용하여 표면에 1092계의 MOS 커패시터를 형성한 뒤. 개별 소자에 대해 I-V test를 행하고 이를 통해 얻이진 파괴전압과 누설전류값을 이용하여 결과를 디스플레이 하는 프로그램을 개발하였다. Breakdown실험을 토해서 얻어진 결과를 결정내부의 특성을 관찰하는 SPV결과와 비교함으로써 표면의 상태와 내부의 상태를 연관시키고자 하는 시도를 하였다. 결함이 존재하는 지역의 커패시터는 결함이 존재하지 않는 지역과 비교하여 상대적으로 높은 누설전류값을 보였다.

• Transactions of the Society of Information Storage Systems
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• v.10 no.2
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• pp.61-64
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• 2014

Vibration and acoustic noise arise from the Multilayer Ceramic Capacitor (MLCC) because of the piezoelectric effect of dielectric substance which consists of $BaTiO_3$. However, the phenomenon is not analyzed clearly because the MLCC shows different behavior compare with ordinary piezoelectric substance like PZT. Thus, MLCC was tested under the several DC bias conditions and heat treatment effect was also tested and analyzed in this paper. From the test, MLCC shows not only piezoelectric effect but also another physical phenomenon like electrostriction. Also, it was verified that DC bias affect to the piezoelectric constant of MLCC.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2271-2273
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• 2005

The cyclic aging for 14days is performed in order to remove the large amount of the volatiles contained in freshly manufactured cable. And the accelerated water treeing test(AWTT) is performed to accelerate the occurance of the water tree in the dielectric of XLPE. In this paper, we examined the AC breakdown voltage characteristics of the 22.9kV power cable before and after the cyclic aging for 14days and the AWTT. As the result, the AC breakdown voltage of the TR CNCV-W power cable is higher than that of CNCV-W and FR CNCO-W power cable.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1457-1459
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• 2003

Space charge distributions and behaviors of polystyrene/polyaniline conducting blends were investigated using a pulsed electroacoustic(PEA) method. It was found that positive charges were accumulated near the cathode with increasing polyaniline content in polystyrene/polyaniline when electric field was applied. Breakdown phenomena was investigated by breakdown test and it was observed that dielectric strength was diminished as polyaniline content was increased. By Scanning Electron Microscopy, corss-sectional views of polystyrene/polyaniline conducting blends were observed that the particles of polyaniline were well distributed in polystyrene.