• Title/Summary/Keyword: Abnormal Vibration

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A Study on the Abnormal Heating of Circuit Breaker in Panel Board by Poor Connection (분전반 내 차단기의 접속불량에 의한 이상발열에 관한 연구)

  • Kim, Hyang-Kon;Kim, Dong-Woo;Choi, Hyo-Sang;Choi, Yong-Sung;Choi, Chung-Seog
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.10-14
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    • 2008
  • In this paper, abnormal heating of circuit breaker in panel board by poor connection was studied. Firstly, calculation method of contact resistance shown in IEC 60943 was examined. Secondly, concerning abnormal heating of circuit breaker in panel board, field measurements were performed. Field measurements showed that locally abnormal heating by poor connection could be detected, therefore, in that case, immediate action was needed. Finally, experiments regarding abnormal heating between terminal of circuit breaker and electric wire were conducted. The results showed that abnormal heating above $180^{\circ}C$ was measured. Also, in the results of analysis of electrical waveforms according to load current, voltage drop occurred around poor connection, and the oxide was generated according to mechanical vibration. In order to prevent electrical disaster caused by poor connection, adequate torque should be applied to electrical connection, and periodic check-ups are needed.

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Diagnosis for Induction Motor from Abnormal Vibration (이상진동에 의한 유동전동기의 진단)

  • 양보석;김남설;장우교;신광재
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.04a
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    • pp.122-127
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    • 1994
  • 본 논문에서는 산업용으로서 널리 이용되고 있는 3상 유도전동기의 전기적결함에 의해 발생하는 전자진동문제를 체계적으로 검토하고, 이를 이용하여 전동기 진동이 진단법을 신경회로망을 이용하여 구축한다. 그리고 그중에서 비교적 자주 발생하는 공극(air-gap)의 정적편심에 대해 실험을 수행하고, 그 결과를 신경회로망을 이용한 진단법에 적용하여 본 진단법의 유용성을 확인한다. 또한 현장에서 발생된 전기적인 결함에 대한 진동측정 data를 이용하여 진단이 정상적으로 수행되는가를 조사하여 본 진단법의 가능성을 조사한다.

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A Study on an Automatic Diagnosis System using the Abnormal Vibration Characteristics of Rotating Machine (회전체 이상 진동특성을 이용한 자동 진단시스템에 관한 연구)

  • 배용채;황원걸;기창두
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1995.04a
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    • pp.360-366
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    • 1995
  • 국내 발전소에서 사용하고 있는 대형 회전 기계인 터빈의 상태 진단 기능을 높이기 위하여 터빈에서 발생 될 수 있는 이상 진동의 특성을 파악하고 이를 이용하여 이상 진동의 발생 가능성을 확률적으로 출력하는 새로운 알고리즘을 개발하였으며, C-언어로 프로그램하여 이를 검증하였다. 이상과 같이 본 연구에서 제안한 알고리즘을 이용한 자동 진단 시스템을 통하여 각각의 이상 진동에 대한 진단을 수행한 결과 양호한 판정 결과를 보였으며, 터빈 이상 진동에 대한 자동 진단의 가능성을 입증하였다.

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Oil Whip Phenomena and Countermeasure on Steam Turbine in 350MW Load Thermal Power Plant (350MW급 화력 발전소 증기터빈의 오일 휩 현상 및 대책)

  • 구재량;김연환;배용채;김계연
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1015-1019
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    • 2001
  • There are several bearing systems at the large steam-turbines in thermal power plant. The bearing system is one of the most important parts of rotating machinery. The steam turbine vibrations mainly depend on the bearing oil and the shaft alignment condition. This paper describes on the steam turbine abnormal vibration due to the oil whip in terms of the shaft alignment in the thermal power plant.

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Dynamic characteristic for vibration mount of MG-Set (전동-발전기의 방진 마운트에 기인한 공진현상 및 동특성 규명)

  • Yoo, Musang;Oh, Kyonghan;Joo, Ingouk;Kim, Hyojin;Roh, Cheolwoo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.816-821
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    • 2013
  • This case study presents a practical method to reduce resonant vibration of generator-motor set. The generator is driven at 1800rpm by induction integral motor. The vibration is below alarm limits, but the dominant frequency of vibration is sub-synchronous and close to that of bearing fault signal in spite of new bearings. To find an mechanism of abnormal vibration, ODS and Modal analysis is carried out. The measured modal characteristics were compared with those of FE Analysis. The ODS mode at rated speed is consistent with system natural frequency mode that is excited by bearings. To reduce vibration level, the isolation mount at system base is changed with new rubber mount for lower natural frequency.

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Lateral Damper of Subway Vehicle for Preventing Abnormal Impact (지하철 전동차 비정상 충격 방지를 위한 횡댐퍼에 관한 연구)

  • Shin, Yujeong;You, Wonhee;Park, Joonhyuk;Hur, Hyunmoo;Jeon, Juyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.17-23
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    • 2013
  • In a subway vehicle, a lateral damper is used for compensating the lateral stiffness deterioration due to the air-spring as a secondary suspension. This lateral damper can reduce the lateral vibration of the carbody. When the damping force of the lateral damper is lowered, the running stability and ride quality of the subway vehicles worsens and the lateral motion of the carbody is increased. In this study, the lateral displacement variation of the carbody according to the damping force of the lateral damper was analyzed by multi-body dynamics to solve the abnormal impact problem during vehicle operation. Furthermore, the noise and vibration due to abnormal impact were considered. An adequate damping coefficient of the lateral damper for the subway vehicle treated in this paper was suggested for preventing abnormal impact.

The Effects of an Abnormal Adjusting Intake and Exhaust Valves on the Combustion Characteristics of SI Engine (흡.배기 밸브의 밀착이상이 엔진연소특성에 미치는 영향)

  • Park Kyoung-Suk;Son Sung-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.3 s.168
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    • pp.123-129
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    • 2005
  • The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis fur developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.

Studies on the Nutrition under Abnormal Environment(I) -Nutrition under Vibration- (이상환경하(異常環境下)의 영양문제(營養問題) 연구(硏究)(제1보) -진동하(振動下)의 영양문제(營養問題)-)

  • Yu, Jong-Yull
    • Journal of Nutrition and Health
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    • v.4 no.4
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    • pp.15-23
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    • 1971
  • On the assumption that the supplementation of certain nutrients or foods to the rice diet (low protein, low fat, and low vitamins) may decrease, to some extent, the degree of suffering from abnormal environments, such as vibration, noises, gases, dusts, smog etc. a series of experiments were started. As the first report the nutrition under vibration was studied in this experiment. Sixty (60) young growing male rats weighing about 65 grams were used, grouping to five (5) groups, twelve (12) rats each group. They were fed on the following five (5) experimental diets: rice diet (basal diet), rice diet+casein, rice diet+vitamins, rice $diet+{\alpha}-tocopherol$, and rice diet+ginseng powder (see the tables 1 and 2) for the period of 14 weeks experiment. During the experiment period the half number of the rats of each group were exposed to the three (3) hours vibration every day. The protective effect of each diet against the vibration may be summarized as follows. 1. The growth of rice diet group was impaired significantly under vibration, However, those of other groups (protein-supplemented, vitamin-supplemented, ${\alpha}-tocopherol-supplemented$ and ginseng-supplemented groups) were impaired much less compared with rice diet group. 2. The feed efficiency of the rice diet group was decreased significantly under vibration. It is estimated that the biological availability of nutrients was impaired under this environment. On the other hand, the feed efficiencies of protein supplemented, of vitamin supplemented, and of ginseng supplemented groups were not decreased under vibration, statistically. 3. There is tendency that the food spillages of vibration groups are higher than those of non-vibration groups. Especially it seems true in the case of rice diet group. The food spillage may be, to some extent, related with mental nervousness of animals. From the point that the food spillage of ginseng supplemented group is significantly lower than those of other groups it is thought ginseng acts some good role in protecting nervous system from suffering from vibration. 4. In all groups except protein supplemented group, liver fat of vibration group tends to be higher than that of non-vibration group. 5. It shows that, in general, the serum alkaline phosphatase activity of the vibration group is significantly higher than that of the non-vibration group. It seems that there may be, to some extent, corelation between the amount of liver fat and serum alkaline phosphatase activity. 6. There is tendency that, in rice diet group, the organs of vibration group are smaller than those of non-vibration group, especially lung is so. It is thought that this may be due to the poor growth of whole body size in vibration group.

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Monitoring of Wafer Dicing State by Using Back Propagation Algorithm (역전파 알고리즘을 이용한 웨이퍼의 다이싱 상태 모니터링)

  • 고경용;차영엽;최범식
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.6
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    • pp.486-491
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    • 2000
  • The dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. But inferior goods are made under the influence of several parameters in dicing such as blade, wafer, cutting water and cutting conditions. This paper describes a monitoring algorithm using neural network in order to find out an instant of vibration signal change when bad dicing appears. The algorithm is composed of two steps: feature extraction and decision. In the feature extraction, five features processed from vibration signal which is acquired by accelerometer attached on blade head are proposed. In the decision, back-propagation neural network is adopted to classify the dicing process into normal and abnormal dicing, and normal and damaged blade. Experiments have been performed for GaAs semiconductor wafer in the case of normal/abnormal dicing and normal/damaged blade. Based upon observation of the experimental results, the proposed scheme shown has a good accuracy of classification performance by which the inferior goods decreased from 35.2% to 6.5%.

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Development of Noise Source Detection System using Array Microphone in Power Plant Equipment (배열형 음향센서를 이용한 발전설비 소음원 탐지시스템 개발)

  • Sohn, Seok-Man;Kim, Dong-Hwan;Lee, Wook-Ryun;Koo, Jae-Raeyang;Hong, Jin-Pyo
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.99-104
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    • 2015
  • In this study, it has been initiated to investigate the specific abnormal vibration signal that has been captured in the power equipment. Array Microphone can be used in order to detect the direction and the position of the noise source. It is possible to track the abnormal mechanical noise in the power plant by utilizing the program and the microphone array system developed from this research. Array microphone system can be operated as a constant monitoring system.