• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.219-223
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• 2004

Since rotor position information is necessary to drive the SRM, absolute-encoder, resolver and incremental encoder is used to detect a rotor position. But, it is not desirable to use a high price encoder and microprocessor under the condition of the simple driving system when precision control is not demanded. In this paper, only using the reflective type two photo-sensors replaces the conventional opto-interrupter and slotted-disk, which not only remove a slotted-disk section but drive three-phase 6/4 pole SRM bidirectionally, Therefore, control circuit can compose common analog device with low price.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1065-1068
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• 2001

Effects of compacting pressure on the electrical and sintering characteristics of Cu25Cr contact material have been investigated. Cu25Cr contact materials were prepared by solid and liquid-phase sintering methods varying compacting pressure. Influence of compacting pressure on electrical characteristics were investigated in the cylindrical stainless-steel vessel using L-C resonant circuit. The physical and electrical properties of solid-phase sintered Cu25Cr material were found to be improved by increased compacting pressure. On the other hand, it was found that compacting pressure had little influence in case of liquid-phase sintered Cu25Cr material. After conditioning, contact resistance of Cu25Cr material was decreased regardless of compacting pressure. With increased compacting pressure, interrupting ability was shown to be increased.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.24-26
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• 2004

For past decade, medium voltage circuit breakers have used the spring-driven mechanical system for interrupting of electric power. However, these mechanisms have many disadvantages of high power consumption, mechanical control components and electrical switching ones for the coil current. Recently, the vacuum interrupter operated by permanent magnet actuator gives outlook on improved characteristic, higher reliability and cost price reduction as well as the feature of simple structure and few components. This paper deals with the dynamic characteristics of permanent magnet actuator used in the medium voltage distribution systems. Coupled finite element method is used to analysis the dynamic characteristics of permanent magnetic actuator and we compared with those of conventional ones.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.479-481
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• 1995

This paper presents a method witch tan improve the dielectric recovery characteristics of UHV class gas circuit breakers by changing the nozzle shape. To calculate the dielectric recovery voltage between electrodes, the flow field and electric field analysis in a 362kV model interrupter has been performed with the commercial programs, RAMPANT and FLUX2D, respectively. As a result, we found that the nozzle shape affects the characteristics of dielectric recovery between electrodes and obtained great improvement of it by the changing the downstream nozzle shape.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.699-700
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• 2008

전기에너지는 가정 및 일반 사업장에서 필수적인 원동력이 되고 있다는 것은 누구나 인식하고 있다, 또한 사소한 전기사고로 인해 발생될 안전사고로 인명이나 전기화재 등을 예방하기 위해 누전이나 과전류 보호에 많은 연구결과로 인해 사고방지에 큰 도움을 주고 있다, 이번 연구는 전기사용안전을 위하여 저압의 누전이나 과전류에 대해서 요함을 인식한 것과 같이 저전압선로에서의 과전압의 발생원인과 과전압의 사고 유형과 과전압 보호장치 구성과 중요함을 알리고 저압회로 차단기에 삽입하여 좀 더 안정된 안전대책과 제품의 개발이나 인증을 득할 기기들의 방안을 제시해본다.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.895-900
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• 2001

It is very important for impact analysis to reflect the dynamic characteristics of materials as well as the static characteristics. As the dynamic behavior of a material is different from the static(or quasi-static) one due to the inertia effect and the stress wave propagation, an adequate experimental technique has to be developed to obtain the dynamic responses for the corresponding level of the strain rate. To determine the dynamic characteristics of materials, the Hopkinson bar (compression type) experiment is carried out. For using dynamic material properties, Johnson-Cook model is applied in impact analysis with explicit finite element method

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.119-120
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• 2010

일반적으로 전선이 낡고 오래되거나 또는 강한 열이나 외부적 충격 등에 의해서 절연이 파괴된 경우 전기화재의 원인이 되는 아크 현상이 발생한다. 이러한 아크 사고는 Arc Fault Circuit Interrupter (AFCI)를 통해 예방할 수 있다. UL1699규정은 AFCI의 성능 시험을 위한 규정으로 구체적인 여러 성능 시험을 제시하고 있다. 그 중 EMI 필터 시험에 대한 부분을 한국의 전기 배선에 맞게 재구성하여 실험하고, 아크 검출에 EMI 필터가 어떤 영향을 미치는지 분석하여 UL에서 제시한 EMI 필터 시험의 타당성을 검증한다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.185-188
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• 2008

An apparatus for serial arc in UL 1699 is implemented Current waveforms of arc and a nonlear load are investigated and a method of arc detection can be considered. Introduction of digital signal processing technologies is suggested to correctly detect arcs of electrical fire pyrognostics. This study is expected to be utilized as the basis of such arc detection researches.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.104-108
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• 1997

The puffer type GCB(gas circuit breaker) has been widely used in modern transmission power system. Understanding the motion of cold $SF_6$ gas flow is essential for the better design of those GCB's. For this purpose, a program using the so-called FLIC(Fluid-In-Cell) method has been developed and applied to a puffer type GCB. The calculated results are compared with those from the measurement and the computation by commercial CFD (Computational Fluid Dynamics) package 'RAMPANT' and show fairly good agreement.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.345-348
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• 1999

An arc model based on the N-S equations modified by adding an energy source term to take account of the arc is developed and solved using Taylor-Garlerkin FEM in the present paper. The numerical method is applied to the simulation of the opening procedure of a puffer type GCB. Moving boundary conditions of the arc chamber during operation is taken into account. Numerical predictions of the temperature profiles at different strokes are presented.