• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.140-142
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• 2003

Small impedances in the superconducting Parallel circuits cause unequal distribution of the currents in the circuits. This results in Quenches or losses in some superconducting parts. This paper presents the fabrication and test results of a multi-interphase transformers (IPT) for equal current distribution in parallel circuits. Test results show that the IPT can effectively make the current distribution uniform in parallel circuits that have unequal resistances.

• 한국초등과학교육학회지:초등과학교육
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• 제19권2호
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• pp.1-13
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• 2000

과학 개념 연구로서 전류 개념에 대한 아동들의 개념 유형이 다양하다는 것이 많은 연구에 의해서 밝혀지고 있으며 과학적인 전류 개념으로 변화시키려는 수업 지도 방안에 대한 연구도 진행되고 있다. 본 연구의 목적은 초등학교 학생을 대상으로 하여 전기 회로와 전류에 대한 개념을 조사하고, 이들 개념간에 어떤 관계가 있는지를 알아보고자 한다. 초등학생에게 실시할 수 있는 전기 회로 개념 검사 문항과 전류 개념 검사 문항을 선택 후 설명식으로 개발하여 초등학교 4-5학년 학생 중 총 163명에게 실시하여 선택결과와 선택 이유를 계통도로 분석하였다. 계통도에 따라 각 개념별 응답 유형의 비율을 구하였고 $\chi$$^2$검증으로 두 개념간의 관계를 찾아보았다. 불이 켜지는 회로 그리기에서는 과학적 모형보다는 전구의 꼭지에만 연결하는 아동의 수가 훨씬 많았다. 회로의 필수적인 요소로 대부분의 아동들이 건전지라 전구, 전선을 선택하였는데, 선택 이유로는 많은 아동이 전구에 불을 켜는 것에 초점을 두었다. 전선의 연결방법과 전구의 연결방법에 대해서는 정답률이 89%로 높게 나타났으며, 전구의 연결방법에 대한 정답률은 77%로 나타났다. 전류의 흐름 유무에 대해서는 대체로 옳은 선택을 하였으나, 회로의 상황에 따라 응답에 차이를 보이며, 주로 건전지는 전류를 공급하고, 전구는 불을 켜는 일, 전선은 전류를 흐르게 하는 길로 생각하고 있었다. 전지와 전구의 연결 방법에 따른 전구의 밝기에 대한 생각은 정답률이 각각 68%, 45%로 높은 편이 아니었다. 전체적으로 볼 때, 전기회로에 대해서 과학적인 생각을 가진 아동들은 그렇지 못한 아동들보다 전류 개념에 대해서도 과학적인 생각을 가지는 경향이 높은 것으로 나타났다. 따라서 전기회로 개념과 전류 개념 사이에는 서로 의미있는 관계가 있다고 결론지을 수 있으며, 전기 회로개념을 과학적으로. 형성한다는 것이 전류 개념을 과학적으로 형성하는데 중요한 요인이 됨을 알 수 있다.

• 한국안전학회지
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• 제15권1호
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• pp.93-99
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• 2000

This paper presents a study on the assessment of electrical fire hazards by electric circuits with leakage. The hazards are evaluated with the energy supplied by earth-leakage currents which flow in the circuits simulating the actual circuit of domestic premises. Also, operating time and current of ELB are measured by an experimental approach. A common specification of ELB used in this paper has a sensitivity of 30[mA] for leakage current working on the current-balance principle. Total charges and energy of leakage currents are calculated quantitatively by a theoretical approach and compared with the results obtained from experiments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.181-184
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• 2001

This paper has been studied driving circuits in electrical valves. Also in this paper, opto-couplers of driving circuit are replaced with digital one chip of Altera company. Designs in order to realization of one chip are carried out with Altera Max Plus II. For compact size and light weight, the realization with one chip is necessary in the electrical valves. This paper has designed and presented the digital schemetic circuits, finally the driving circuits are sucessfully operated with the designed chip and showed the saving of area in the driving circuits of electric valves.

• 컴퓨터교육학회논문지
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• 제10권5호
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• pp.53-60
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• 2007

학습효율의 향상을 위해 본 논문에서는 웹기반 가상실험시스템과 원격실험시스템을 적절하게 통합하여 전기전자회로에 대한 하이브리드 실험시스템을 구현하였다. 먼저, 전기/전자회로 실험에 대한 웹기반 가상실험실을 개발하여 개념학습, 가상실험, 평가등의 3개의 주요 세션과 그에 대한 관리시스템으로 구성하였다. 다음으로 가상실험을 진행하는 동안 발생할 수 있는 현실감의 부족성 문제를 해결하기 위해 전기전자회로에 대한 원격실험시스템을 구현하였다. 제안된 가상/원격실험시스템은 독립적인 형태로 사용될 수도 있지만, 학습효율을 극대화하기 위해서 두 개의 시스템을 통합하여 하이브리드 전기전자 실험시스템을 구현하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.56-59
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• 2001

An effective method of detecting inter-turn short circuits on round rotor windings is described. Shorted-turns can have significant effects on a generator and its performance. A method of detecting inter-turn short circuits on rotor windings is described. The approach used is to measure the rate of change of the air-gap flux density wave when the rotor is at operating speed and excitation is applied to the field winding. The inter-turn short circuits sensor for synchronous generator's field winding has been developed. The sensor, installed in the generator air-gap, senses the slot leakage flux of field winding and produces a voltage waveform proportional to the rate of change of the flux. For identification of reliability for sensor, a inter-turn short circuits test was performed at the West-Inchon combined cycle power plant on gas turbine generator and steam turbine generator. This sensor will be used as a detecting of shorted-turn for field winding of synchronous generator. The purpose of this paper is to describe the design and operation of a sensitive inter-turn short circuits detector. In this paper, development of inter-turn short circuits sensor for field winding of synchronous generator and application in a field.

• 한국자동차공학회논문집
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• 제15권4호
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• pp.154-160
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• 2007

The experimental system, developed in this research, is a teaching material that trains and practices automobile electric circuit in technical high school. This system consists of a textbook, 15 kinds of instruments and 62 kinds of 'Flash' animations. Textbook includes automobile electric circuits and experimental process. Instruments have 23 kinds of drills. Its is composed of electrical relays, motors, switches, light bulbs, electrical lines and power unit so on. 'Flash' animation displays an electrical current flow on circuits actually. Both Dacum method and ISD skill have been conducted to analysis job and design syllabus. The experimental system have been implemented on technical high school class to evaluate its objectivity and effect. It is expected that this system can contribute to studying of car service.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1131-1134
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• 2003

Unknown parameters of a nonlinear system were estimated using a signal compression method. The estimated parameters were natural frequency and tile damping coefficient. This study applied a algorithm using tile comparison of the cross-correlation coefficient between the impulse response from a model and it from the signal compression method. The impulse through linear element included in a nonlinear system could be obtained by the signal compression method. The unknown parameters of the linear element could be estimated by comparing the Bode plots of system's impulse response with them of model's response. In this study, a LSCM(LabVIEW-Signal-Compression-Method) was developed to identify a nonlinear system. The LSCM consisted of National Instrument's (NI) Data Acquisition (DAQ) Board (Model PCI-1200), a monitoring program using LabVIEW software package, DAQ Signal Accessory Board, and 2nd-order electric circuits. The designed electric circuits consisted of resistors, inductors and capacitors. To evaluate the performance of the LSCM, the response from model with known parameters is compared with the response from the real system using the monitoring program. The results from simulation of experiment showed that the developed LSCM provided a reliable estimation performance.

• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.261-266
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• 2018

When the clamp meter approaches the electric path where current is flowing, leakage current can be measured at a distance from the electric current because the induced current increases as the magnitude of the current increases and approaches nearer to the electric path. Therefore, measurements were carried out from a distance to avoid this effect. In addition, the measured values differ depending on the location of the power line that penetrates the ZCT of the clamp meter, thus measurements were performed at a location where this effect was minimized. The fraction of compliant branch circuits, whose leakage current was lower than 1.00 mA, was found to be 69.0% out of the total of 439 branch circuits, while the percentage of compliant branch circuits having an insulation resistance higher than $0.20M{\Omega}$ was found to be 93.2%. The reason why the percentage of compliant branch circuits with low leakage current was low might be due to the inclusion of capacitive leakage current in the total measured leakage current.

• Journal of Power Electronics
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• 제5권3호
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• pp.233-239
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• 2005

In this paper, a new conceptual circuit configuration of a 3-phase voltage source, soft switching AC-DC-AC converter using an IGBT module, which has one ARCPL circuit and one ARDCL circuit, is presented. In actuality, the ARCPL circuit is applied in the 3-phase voltage source rectifier side, and the ARDCL circuit is in the inverter side. And more, each power semiconductor device has a novel clamp snubber circuit, which can save the power semiconductor device from voltage and current across each power device. The proposed soft switching circuits have only two active power semiconductor devices. These ARCPL and ARDCL circuits consist of fewer parts than the conventional soft switching circuit. Furthermore, the proposed 3-phase voltage source soft switching AC-DC-AC power conversion system needs no additional sensor for complete soft switching as compared with the conventional 3-phase voltage source AC-DC-AC power conversion system. In addition to this, these soft switching circuits operate only once in one sampling term. Therefore, the power conversion efficiency of the proposed AC-DC-AC converter system will get higher than a conventional soft switching converter system because of the reduced ARCPL and ARDCL circuit losses. The operation timing and terms for ARDCL and ARCPL circuits are calculated and controlled by the smoothing DC capacitor voltage and the output AC current. Using this control, the loss of the soft switching circuits are reduced owing to reduced resonant inductor current in ARCPL and ARDCL circuits as compared with the conventional controlled soft switching power conversion system. The operating performances of proposed soft switching AC-DC-AC converter treated here are evaluated on the basis of experimental results in a 50kVA setup in this paper. As a result of experiment on the 50kVA system, it was confirmed that the proposed circuit could reduce conduction noise below 10 MHz and improve the conversion efficiency from 88. 5% to 90.5%, when compared with the hard switching circuit.