• 한국전기전자재료학회논문지
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• 제14권4호
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• pp.297-301
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• 2001

In this paper, the temperature distribution and thermal stress analysis of 50kVA pole cast resin transformer for power distribution are investigated by FEM program. The one body molding model (Model 1) and air duct model (Model 2) are designed and their temperature distribution are analysed. The temperature rise value is about 105.5 deg in the model 1 and 65.28 de in the model 2. The temperature change of secondary winding is more than primary winding according to load ratio. The concentration part of Von Mises Stress occurs at interface between glass fiber and epoxy.

• 대한전기학회논문지
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• 제43권2호
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• pp.206-215
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• 1994

A method for simulating general characteristics and temperature characteristics of discharging SCR of the capacitor discharge impulse magnetizer-magnetizing fixture system using SPICE is presented. This method has been developed which can aid the design, understanding and inexpensive, time-saving of magnetizing circuit. As the detailed characteristic of magnetizing circuit can be obtained, the efficient design of the magntizing circuit which produce desired magnet will be possible using our SPICE modeling. Especially, computation of the temperature rise of discharging SCR is very important since it gives some indication of thermal characteristic of discharging circuit. It is implemented on a 486 personal computer, and the modeling results are checked against experimental measures. The experimental results have been achived using 305[V] and 607[V] charging voltage, low-energy capacitor discharge impulse magnetizer-magnetizing fixture of air cleaner DC motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2284-2289
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• 1998

The Rotor Stress Indicator is an integrated system of hardware and program components which has been designed to read an assortment of turbine temperature and speed input devices, perform an analysis of the temperature induced stresses and output pertinent temperature and stress information to guide the turbine operator during turbine prewarming, start-ups, load changes, and shut-downs. The purpose of the RSI is to provide guidance to the plant operator during startup, shutdown, loading, and unloading of the turbine. Since the stresses are a function of the temperature changes to which the turbine is exposed, the RSI also provides guidance for operation of the boiler main steam and reheat steam temperatures as they affect the rotor stresses. This may permit more efficient overall boiler turbine start-ups. In this paper, new rotor stress analysis algorithm for RSI is introduced and compared with present system which has been used in thermal power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.378-380
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• 1998

In this paper, to analyse the temperature rise of the traction motor the methods evaluating the heat sources and heat transfer coefficients are represented. And the results of temperature analysis of the 3- designed cases of traction motor also are represented. In case of KERI01, the tempeature rise of the rotor is higher than DW01 and DW02. In the stators, case of DW01 is presented higher temperature rise than DW02 and KERI01.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.813-815
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• 2000

This paper is concerned with the development of PC based computer simulation and design tools for auto-expansion SF6 circuit breaker with the arc rotary. The simulation model takes into account radiation transport, turbulence enhanced momentum. energy transport. The conversation gas dynamic equation together with Maxwells equations are solved. For the arc simulation the straightforward procedure has been used. The temperature, gas density and velocity space distributions within the circuit breaker are simulated in details. The presented results show that the computer simulation of gas flow in SF6 interrupter is a subject of much interest for design and optimization of contacts. The presented results show that the shape and sizes of contacts are chosen by this tool from judiciously compromise between electrical breakdown strength and interruption ability that are functions of gas flow parameters.

• 대한전기학회논문지
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• 제36권11호
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• pp.783-789
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• 1987

It is anticipated that the accuracy of the numerical value obtained by curve fitting is mainly governed by how to evaluate the term of exponential integral involved in the theory of TSC, so that evaluation process of the instegral term concerned is replaced by Romberg numerical integral method instead of the conventional approximation method of asymtotic expansion or Simmons-Tayler with expectation to get the improved accuracy. In order to examine the effectiveness of the proposed method, the new algorithm is tried to adapt to the peak of TSC observed about 356 K im the specimen of polyethylene terephthalate in which carrier is injected by means of corona dischargel. As theresults, it is confirmed that the proposed method being cooperated with Romberg numerical intergral intergral is superior to the existing conventional curve fitting method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.387-390
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• 2000

The life of transformer is significantly dependent on the thermal behavior in windings. To analyse winding temperature rise, many transformer designer have calculated temperature distribution and hot spot point by finite element method(FEM). Recently, numerical analyses of transformer are studied for optimum design, that is electric field analysis, magnetic field, potential vibration, thermal distribution and thermal stress. Therefore design time and design cost are decreased by numerical analysis. In this paper, the temperature distribution and thermal stress analysis of 50kVA pole cast resin transformer for power distribution are investigated by FEM program. The temperature change according to load rates of transformer also have been investigated. We have carried out temperature rise test and test results are compared with simulation data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2043-2045
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• 2005

현재 점화코일은 소형화 및 친환경성을 위해 에폭시 몰딩 절연층으로 변화되었다. 그러나 에폭시 몰딩으로 변환됨에 따라 점화코일 내부 절연층에 대한 절연진단 및 노화에 대한 정확한 진단의 어려움으로 적절한 교체시기를 예측하기 더욱 어려워졌다. 그로 인해 점화장치부분에 대한 예기치 못한 사고는 대형사고 유발을 초래할 수 있다. 이에 본 논문에서는 비파괴검사의 일종인 부분방전을 이용한 열화검출을 연구하기 위해 열화에 따른 위상각-방전전하량-방전빈도수의 분포 특성을 조사하였다. 또한 방전 발생의 분포가 동일 조건에서도 매우 불규칙성을 가지고 있으므로 데이터의 정량화를 위해 불규칙적인 통계처리를 위한 와이블 분포를 사용하여 기기의 고장시간예측을 조사하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1073-1075
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• 2004

Permanent magnet high-speed machines are small size compared with general motor of the same power and so must minimize generating heat, as well rotor structure is simple and strong for born centrifugal force. Especially, Material of each part is given thermal limit therefore temperature distribution vary important. In this paper, heat transfer coefficient of permanent magnet high-speed machines with 5-kW 40,000 rpm is calculated and temperature distribution due to power loss is predicted by finite element analysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.144-145
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• 2007

Phase change random access memory is one of the most promising candidates for next generation non-volatile memories. However, the high reset current is one major obstacle to develop a high density PRAM. One way of the reset current reduction is to develop the new phase change material. In this paper, to reduce the reset current for phase transition, we have investigated the effect of phase change material parameters using finite element analysis.