• Title/Summary/Keyword: Malfunction phenomenon

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A Study on PCB's Latch-up Phenomenon by External Electrical Surge (외부 전기서지에 의한 전자회로기판 Latch-up 현상 고찰)

  • Ji, Yeong-Hwa;Jo, Sung-Han;Jung, Chang-Gyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.2089-2092
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    • 2010
  • There are many cases that interrupt the production process because of malfunctions caused by electronic circuit boards which control equipment, but it is difficult to distinctly identify the causes in many cases. Especially, CMOS devices with the control logic circuit return automatically to normal state after their own faults. Therefore it is not easy to analyze the problems with electronic circuit boards. Recently, nuclear power plant experienced a failure due to the malfunction of electronic circuit boards and it was identified that the reason of the malfunction was because of latch-up phenomenon caused by external surge in electronic devices. This paper presents the causes and the phenomenon of latch-up by experiment and also a way using counter EMF diodes, noise filters and surge protective devices to prevent latch-up phenomenon from electronic circuit boards, finally confirms the effectiveness of the result by experiment.

Research on the Correlation of Control Malfunction with Induced Voltage of Control Signal Line According to Voltage Change of a Power Line

  • Kang, Dong-Woo;Kim, In-Gun;Ham, Sang-Hwan;Kim, Sung-Yul;Bae, Sungwoo;Kim, Dae-Nyeon;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.775-780
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    • 2016
  • This induced voltage measurement test and electromagnetic field simulation are related to the possibility of control signal malfunction by power line. Through an experiment, this research analyzed whether the voltage causing control malfunction according to the on/off status of power permitted to power line was induced to control signal line. Also, the research calculated the voltage induced to control signal line and examined the phenomenon by conducting an electro-magnetic field-specific simulation through the finite element method for the cable model used in the experiment.

A Study on Development of Maintenance Skill Training Simulator for Railway Vehicle

  • Jung, NoGeon;Kim, BoSung;Lee, JaeBong;Lee, SangMoon;Koo, KyungWan;Kim, JaeMoon
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.2
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    • pp.113-116
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    • 2015
  • Generally, in the railway vehicle the driving force of gravity happens by the high-speed running and the repetitive impulse cause the degradation and the malfunction phenomenon shows differently because the durability of each component changes according to the internal and external causes. The maintenance of propulsion control device which is played the very important role as to the stable service of the railway vehicle is greatly important among them. Therefore maintenance training propulsion control device simulator is needed to maximize learning through repetition and improve the maintenance practical skills training. This paper designed the railway vehicle running device with a miniature for the railway vehicle maintenance training and developed a propulsion control device simulator equipped the imitation steering wheel.

A Study on LED Driver Compatible with Triac-dimmer Employing Active Bleeder (능동 블리더 회로를 적용한 조광기 호환용 LED 구동회로에 관한 연구)

  • Yeom, Bong-Ho;Hong, Sung-Soo;Kim, Taek-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.4
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    • pp.297-302
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    • 2014
  • In this paper, a LED driver compatible with TRIAC-dimmer applying active bleeder is proposed. If TRIAC-dimmer is connected with LED driver, flicker phenomenon occurs by TRIAC malfunction. In order to prevent this problem, a current over holding current must flow into TRIAC. Therefore, additional circuit compatible with TRIAC-dimmer is required to provide enough current. Passive bleeder has power loss in whole operation period. The proposed circuit apply a valley-fill circuit for power-factor-correction and a novel active bleeder detecting malfunction point of TRIAC. Therefore, it prevent malfunction of TRIAC-dimmer and have advantage of higher efficiency than passive bleeder. To verify the validity of proposed circuit, 13W-lighting LED driver prototype has been proposed.

A Study on Searching Algorithm for Malfunction Pattern of Protection Devices in Distribution System with PV Systems (태양광전원이 연계된 배전계통 보호협조기기의 부동작패턴 탐색알고리즘에 관한 연구)

  • Kwon, Soon-Hwan;Tae, Dong-Hyun;Lee, Hu-Dong;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.9
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    • pp.652-661
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    • 2020
  • Recently, the Korean government developed the RE3020 (renewable energy) policy to overcome environmental problems, such as fine dust, climate change, and large-scale PV systems interconnected with a distribution system. When a large-scale PV system is interconnected in the distribution system, however, a malfunction can occur, and the protection devices may not be operated because of the dividing effect depending on the magnitude and direction of fault current as well as connection types and location of the PV system. Therefore, this paper proposes a search algorithm for the malfunction pattern of protection devices based on various scenarios, when large-scale PV systems are operated and interconnected in a distribution system. This paper presents a malfunction mechanism of protection devices according to the installation locations of recloser (R/C). Furthermore, the modeling of a distribution system with large-scale PV systems was performed using Off-DAS S/W, and the malfunction patterns of protection devices were analyzed based on a range of scenarios. From the simulation results with the proposed model and algorithm for searching for protection devices, it was confirmed that they are useful and effective in identifying a malfunction phenomenon depending on the installation location of the R/C and connection type of PV system.

A Study on the Countermeasure Algorithm for Power System Disturbances in Large Scale Fuel Cell Generation System (대용량 연료전지시스템의 계통외란 방지알고리즘에 관한 연구)

  • Choi, Sung-sik;Kim, Byung-ki;Park, Jae-beom;Rho, Dae-seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.711-717
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    • 2016
  • Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

A Study on the Improvement of the Mast Design for Wind Detector (풍향풍속 검출기 마스트 설계 개선에 관한 연구)

  • Kim, Dong-Young;Park, Hae-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.5
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    • pp.98-107
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    • 2021
  • During the sea trial test for the aerovane in AOE-II, a malfunction occurred in the wind detector movement around 40 to 90° on the starboard side and around 270 to 320° on the port side. The purpose of this study was to analyze and improve the cause of the above phenomenon. The wind detector was covered with a mast structure and was not affected directly by the blowing wind, and a vortex air current was formed behind the mast structure, causing the motion malfunction. The above problem was solved by moving and installing the wind detector on the newly installed mast yard. After conducting vibration analysis and reviewing the effects of vibration, the wind detector was installed in the new mast yard and verified by a sea trial test. Since the improvement plan was slightly effective, the position of the wind detector moved away from the mast on the new mast yard and was re-verified through a sea trial test. The movement malfunction of the wind detector did not occur, confirming that it is an appropriate improvement plan.

A Study on the Detection of Asynchronous State of the Synchronous Generator

  • Choi, Hyung-Joo;Lee, Heung-Ho
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.405-412
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    • 2013
  • This paper includes new protection concepts and practices to avoid mechanical damage of three-phase transformer by asynchronous operation of synchronous generator. this failure is often caused just after synchronous generator was connected to the grid because of a malfunction of the controller or misconnections of the synchronous devices. The results of the studies on the analyzing the phenomenon of asynchronous operation experienced in Korea and rapidly detecting asynchronous state are descrived.

EMI Mesh Development for the PDP using Electroforming (Electroforming을 이용한 PDP용 EMI 메시 개발)

  • Kwon, H.H.;Beom, M.W.;Lim, S.Y.;Hwang, C.S.;Park, D.S.;Lee, T.W.
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.1
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    • pp.108-113
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    • 2011
  • There are a lot of PDP TV for a plasma discharge pulse voltage generated by the use of electromagnetic waves. EMI mesh film is near Infrared ray caused by malfunction of the remote control intended to prevent this phenomenon. In this study, the formation of fine pattern by making the mold is imprinted on the film sheet. EMI mesh film has been granted by filling in the conductive material region imprinted with electroforming in the manufacture of resistance. The fine patterns fabricated with electroforming facility thickness of homogenization process technology were established to optimize the working conditions.

ACOUSTIC EMISSION IN BENDING FATIGUE PROCESS OF CARBURIZING SPUR DEAR BY AE SOUTCE LICATION

  • Sentoku, Hirofumi;Yamato, Hiroyuki
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.142-145
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    • 1995
  • It is important from prevention of the malfunction and an important accident by the failuer, to detect a failuer in revolution devices. The acoustic emission(AE) method is expected as means that defects an abnormal phenomenon of revolution devices earlily and utilized. Although a research example by the AE method is reported regarding a gears, little reserch has been conducted using the AE method for running gears in a bending fatigue process of spur gear teeth. Therefore, in this report, with two micro AE sensors attached to the side of the gear, AE was measured in a bending fatigue process of a carburizing gear by using the power circurating-type machine and AE source location in gear teeth were required. By various analysis in these data, the AE characteristics in the fatigue damaging process of the gear tooth were determined.

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