• 대한기계학회논문집B
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• 제27권7호
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• pp.938-947
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• 2003

In this paper, we derived the formula for estimating the power of the electric motors needed to operate the Decanter-type centrifuge. In the derivation of the formula the sludge-removal torque is to be supplied from the formula derived in the first paper. The intricate nature of the transmission mechanism in the planetary gear trains of the sludge-removal power and torque has been clarified in this second paper. In particular we considered two-motor system, where the main motor drives the machine while the differential-speed control motor plays the role of braking in adjusting the differential speed. Sample calculation for the specific design treated in the first paper showed that the selection criterion for the main motor depends on the lower limit of the differential speed; when the lower limit is set low, it should be selected based on the steadily operating power, while it should be selected based on the starting power when the lower limit is set high. The total power required by both the main motor and the differential-speed control motor increases as the differential speed is decreased. It is suggested that the power loss in the differential-speed control motor could be minimized by attaching an electric generator to it.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1203-1205
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• 1992

Due to poor energy resources, the importance of energy saving has been greatly emphasized. It can be one method of energy saving to reduce the power. The AC adjustable speed drive systems show excellent efficiency, which have been developed in recent years. The adjustable speed drive system improves the efficiency in lightly load condition and extend the life span of motor by limiting the over-current at starting. The main topic of study is the results of energy saving and emergency transfer.

• 대한전기학회논문지
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• 제43권6호
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• pp.1001-1009
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• 1994

The present paper deals with a new developed sensor for measuring the time-varying magnetic fields and describes the experimental results of trasient magnetic field that takes place during the operations of electric appliance. The operation principle of the self-integrating magnetic field sensor by using coaxial cable is analyzed and a calibration investigation is carried out. The frequency bandwidth of the magnetic field measurement system is from 40 Hz to about 300 kHz. The magnetic field induced by the starting and/or operation of electric appliance mainly includes the odd harmonics such as the third, the fifth and the seventh harmonics. The magnetic field intensity caused during the operation of ultrasonic washer is inversely proportional to distance, this correspodns to induction component. As a result, it was known that the odd harmonics of magnetic field in the desing of electromagnetic shield employed for protecting electronic circuit and control devices have to be considered.

• 전력전자학회논문지
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• 제5권5호
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• pp.515-521
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• 2000

본 논문은 전동차용 추진장치인 IGBT VVVF 인버터의 현차시험에 관한 것이다. IGBT VVVF인버터는 1,650kVA급으로 개발되었다. 추진 인버터의 신뢰성과 성능을 확인하기 위하여 서울시 지하철 6호선에서 본선시험을 하였다. 시험 차량구성은 4M4T로 구성되었으며, 전장품은 4대의 VVVF인버터, 16대의 견인전동기 및 2대의 SIV로 구성하였다. 추진장치는 1C4M으로 구성하였다. 현차시험을 통하여 추진용 인버터의 우수한 가·감속 능력과 가가속도 특성 및 구배에서의 등판능력을 확인 할 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.548-553
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• 2003

Battery supplies Each Electric device in Railway vehicles with Control Power. When Battery is overchargedjustly, the battery voltage is not satisfied with the minimum operating voltage, CVCF Inverter(SIV) is supplied with external Power supply or the other railway vehicles and start up CVCF Inverter. In this paper to improve this problem, Dead battery Starter system is proposed. When the battery voltage is not satisfied with the minimum value.turn on the Dead Battery Starter switch, and the Dead Battery Starter supplies the control power to the SIV controller from the line voltage. With this Dead Battery Starter system, the train can be operated when the battery is not proper status. Dead Battery Starter is designed by ROTEM and will be delivered to Attiko Metro Series 2.

• Journal of Power Electronics
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• 제4권2호
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• pp.96-101
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• 2004

This paper presents an application of SRM drive for LSEV(Low Speed Electric Vehicle). In this paper, a 5〔㎾〕 SRM for a traction of a LSEV is to design and investigate the characteristics of the drive system. The main design parameters and control strategy are given. In the control method, a current control, for the soft-starting technique at a starting operation, is adopted. In the high speed range, an angle control technique is implemented, for a high efficiency drive of SRM. Some experimental tests are executed to find the drive performances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1560-1561
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• 2007

Electrodeless fluorescent lamp exhibit two modes of operation : a low density mode in which the power is capacitively coupled to the plasma and which is known as the E-mode, and a higher density mode which is an inductive discharge known as the H-mode. The transition between these two(E to H) mode exhibits hysteresis. It is observed that transition currents change at different frequencies and hysteresis exists not only between the starting and minimum maintaining currents of the electromagnetic mode (H mode) discharge but also between the starting and minimum maintaining currents of the electrostatic mode (E mode) discharge. Hysteresis effect can be important role in dimming system.

• 한국산업융합학회 논문집
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• 제25권3호
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• pp.433-441
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• 2022

In general, in an emergency generator system for an electric facility including an induction motor load, an emergency power generation facility larger than the facility load capacity is built due to the initial starting current of the induction motor. In order to reduce this economic burden, various methods to reduce the inrush current of induction motors are applied to suppress the additional expansion of generators due to the reduction of power generation facilities and the increase in electrical facilities. Among these methods, when a system with a built-in soft start function of an induction motor using an inverter is built, it is the best way to reduce the inrush current of the induction motor to less than the rated current. However, in this case, the installation cost of the inverter to drive the induction motor increases. This paper proposes a soft start method of an induction motor by expanding the frequency and voltage control operation area of an emergency generator. In addition, proposed a speed calculation method based on power factor information, which is essential information for stable soft start of an induction motor, and a method for generating a speed command value of the governor for starting with maximum torque.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.772-776
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• 2011

개발 중인 중형 전기추진 무인기는 전력원으로 태양전지, 연료전지, 이차전지를 사용한다. 전력변환기 및 컨버터를 없이 전압 매칭을 통해 전력원을 선정하고 단품시험을 수행하였다. 여러 종류의 전력원을 통합하여 사용함에 따른 각 전력원 별 특성파악 및 에너지 사용 비율을 정량적으로 평가하기 위해 5시간 지상통합시험을 수행하였다. 그 결과 배터리는 시동 및 과도상태에서 다른 동력원에 비해 빠른 출력반응을 보였으며, 연료전지와 태양전지는 순항영역에서 주 전력 공급원의 역할을 수행함을 확인하였다. 사용한 에너지 비율은 연료전지, 태양전지, 배터리가 각각 68%, 29%, 2.5%임을 알 수 있었다.

• 한국항공우주학회지
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• 제39권11호
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• pp.1052-1059
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• 2011

본 논문에서는 연료전지, 태양전지, 배터리를 동력원으로 사용하는 전기추진시스템의 전력특성변화에 대한 시뮬레이션에 관하여 기술하였다. 각 전력원을 통합하여 400 W급 전기 추진시스템에 대하여 모델링 및 시뮬레이션을 수행하였다. 그 결과 능동 제어로직이 없어도 배터리는 시동 및 과도상태에서 다른 동력원에 비해 빠른 출력반응을 보였으며, 연료전지와 태양전지는 순항영역에서 주 전력 공급원의 역할을 수행함을 확인하였다. 비행 후 동지때 SOC는 24.2%이고, 하지에는 93%로 시스템 안정성 확보 및 효율적인 동력분배 차원에서 적정 SOC를 유지하기 위하여 능동 전력제어가 필요함을 알 수 있다.