• JOURNAL OF ELECTRICAL WORLD
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• no.7 s.127
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• pp.102-103
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• 1987

유도전동기의 시동시에는 정격전류의 수배의 전류가 흐른다고 한다. 현재는 농형의 유도전동기로 3상200V의 50KW나 75KW의 비교적 용량이 큰 전동기가 $Y-{\Delta}$시동으로 운전되고 있다. 이 정도의 용량이 되면 시동전류도 커져서 2대가 동시시동과 같은 경우에는 고압측의 차단기가 동작하는 경우가 있다. 또한 전동기가 75KW나 되면 저압측이 퓨즈나 차단기과의 동작협조가 곤란해진다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.36-45
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• 2005

This paper addresses the application of motor current spectral analysis for the detection of rolling-element bearing damage in induction machines. We set the experimental test bed. They is composed of the normal condition bearing system, the abnormal rolling-element bearing system of 2 type induction motors with shaft deflection system by external force and a hole drilled through the outer race of the shaft end bearing of the four pole test motor. We have developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module is checking stator current The effects on the stator current spectrum are described and related frequencies are also determined. This is an important result in the formulation of a fault detection scheme that monitors the stator currents. We utilized the FFT(Fast Fourier Transform), Wavelet analysis and averaging signal pattern by inner product tool to analyze stator current components. Especially, the analyzed results by inner product clearly illustrate that the stator signature analysis can be used to identify the presence of a bearing fault.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.3
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• pp.45-52
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• 2006

In this paper, we analyze on the effect of LCR filter to mitigate transient overvoltage on the high voltage induction motor fed by H-bridge cascaded 7-level inverter. The switching surge voltage that it was occurred in inverter appears transient overvoltage at the motor input terminal. the transient overvoltage becomes the major cause to occur the insulation failure by serious voltage stress in the stator winding of high voltage induction motor. The effect of transient overvoltage appears more serious in high voltage induction motor than low voltage induction motor. We selected LCR filter for reduction of the transient overvoltage. Consequently, we demonstrated that the LCR filter connected to the invertor output terminals greatly reduces the transient voltage stress and ringing. The results of simulation show the suppression of transient overvoltage at the motor end of a long cable. using EMTP

• The Journal of the Acoustical Society of Korea
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• v.30 no.8
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• pp.446-460
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• 2011

The use of induction motors has been recently increasing with automation in aeronautical and automotive industries, and it playes a significant role. This has motivated that many researchers have studied on developing fault detection and classification systems of an induction motor in order to minimize economical damage caused by its fault. With this reason, this paper proposed feature vector extraction methods based on STE (short-time energy)+SVD (singular value decomposition) and DCT (discrete cosine transform)+SVD techniques to early detect and diagnose faults of induction motors, and classified faults of an induction motor into different types of them by using extracted features as inputs of BPNN (back propagation neural network) and multi-layer SVM (support vector machine). When BPNN and multi-lay SVM are used as classifiers for fault classification, there are many settings that affect classification performance: the number of input layers, the number of hidden layers and learning algorithms for BPNN, and standard deviation values of Gaussian radial basis function for multi-layer SVM. Therefore, this paper quantitatively simulated to find appropriate settings for those classifiers yielding higher classification performance than others.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.313-315
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• 2000

본 논문에서는 프랜트 설계 단계에서 안정도 해석을 행함에 있어 부하모델의 차이가 안정도 해석 결과에 미치는 영향을 비교 평가하였다. 플랜트 부하의 대부분인 유도전동기 모델을 달리 적용함에 따라 안정도 해석 시 최대 허용 고장제거시간이 매우 다르게 나타난다는 것을 보여 주었다. 또한 유도전동기의 모델 표현을 달리함에 따라 고장제거 후 모선의 전압회복 특성과 전동기 속도 회복 특성이 매우 달라짐을 보여 주면서 산업플랜트 보호계전 시스템 설계를 위한 안정도 해석 시 유도전동기 모델 적용방법에 있어 유의하여 할 사항을 제시하였다.

• ICROS
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• v.3 no.3
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• pp.36-48
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• 1997

본 원고에서는 극 좌표계를 기준으로 하여 추정기를 구성함으로써 속도 검출기가 없는 유도전동기의 회전자 자속 및 회전 속도를 정확히 추정해 내고, 다시 이 정보를 이용하여 유도전동기를 고성능으로 제어할 수 있는 드라이브 시스템의 구현 과정과 이를 이용한 간단한 실험 결과에 대하여 소개하였다. 본 원고에서 제시한 몇가지의 실험 결과들은 소프트웨어의 알고리즘에 의하여 전동기의 회전축에 부착된 속도 검출기는 충분히 대치될 수 있음을 말해주는 것이므로, 속도 검출기가 가격과 내구성 등에서 실제적으로 산업 현장에 적용하기에 많은 문제점을 안고 있다는 점을 감안할 때 그 유용성을 입증하는 것이다.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.327-329
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• 1999

본 논문은 3차원 유한요소 프로그램을 이용한 농형 유도전동기의 정자장을 해석한 것이다. 2차원영역에서 해석하기 어려운 누설 인덕턴스를 3차원으로 해석하여 설계 파라미터 선정에 도움을 주고자 하였다. 유도전동기의 공극 자속밀도 분포와 누설 자속밀도 분포를 고찰하고 1[turn]의 coil에 의해 발생하는 자속의 량과 전동기 내부로 통과하는 자속의 량을 비교하여 누설 인덕턴스를 계산할 수 있었다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.924-926
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• 2003

단상 전원에 의해 기동 및 운전되는 영구 자석형 동기전동기는 일반 단상 유도전동기에 매우 높은 효율을 갖게 되지만, 회전방향을 정하기가 어렵다. 본 연구에서는 커패시터를 사용하는 커패시터 운전 유도 전동기와 같은 구조에 회전자를 영구자석을 사용하는 경우에 대하여 연구하였다. 즉, 회전자 조건에 따른 기동 조건을 계산하고, 이로부터 회전방향을 결정할 수 있어 고효율로 팬부하와 같은 기동토크가 작은 부하에 적용될 수 있을 것으로 기대된다.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.86-92
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• 2009

As increasing of using induction motors, the induction motors faults cause serious damage to the industry. Therefore to find out faults of induction motor is recognized as important problem awaiting solution. But to make matters worse, the faults of induction motors often progress through long time. It means that early diagnosis is very important. Many researches have been progressed and general method of diagnosis is using vibration sensor to diagnose fault of induction motor. However, although it is reliability technique, it demands high price and it is difficult to use. This paper presents an implementation of technique for fault diagnosis of induction motor using wavelet transform based stator current and it is composed with algorithm that decides whether fault existence or not using C++ based on windows software. The algorithm will be accomplished in real-time using current data acquisition board and PC automatically with Neural Network algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.748-757
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• 2007

This paper is intended to solve the technical problem that fails in large-capacity induction motor starting due to serious voltage drop during starting period. One induction motor that is established already can reach in steady-state using reactor starting method but the voltage magnitude of PCC (point of common coupling) has dropped down a little. When the same capacity induction motor is installed additionally in the PCC, where the existing induction motor is operating, voltage drop becomes more serious by starting of additional induction motor. As a result, the additional induction motor fails in starting. Therefore, voltage compensation method is proposed so that all of two induction motors can be started completely. First, modeling technique is described in order to implement starting characteristics of large induction motor. And then, this paper proposes strategic starting scheme by proper voltage compensation that use no-load transformer tap control (NLTC) and step voltage regulator (SVR) for starting of two large induction motors successfully and improving the feeding network voltage profile during the starting period. The induction motor discussed in this paper is the pumped induction motor of 2500kVA capacity that is operating by KOWACO (Korea Water Resources Corporation). Modeling and simulation is conducted using PSCAD/EMTDC software.