• Title/Summary/Keyword: MCCB

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A Study on Improving Arc Quenching Performance of MCCB by FEM (유한요소법을 이용한 배선용 차단기의 아크소호 성능향상에 관한 연구)

  • Kim, Kil-Sou;Lim, Kee-Joe;Kang, Seong-Hwa;Cho, Hyun-Kil;Lee, Gang-Won;Park, Jung-Nam
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.51-54
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    • 2001
  • This Paper is described basic principles of arc quenching in Molded Case Circuit Breaker. We analyzed magnetic blowout forces acting on the arc in contact system when circuit breakers interrupt fault currents in different three models by 3-D FEM(Finite Element Method). The interrupting time simulated is compared with that of short circuit tests. The results of this study derive valid of the simulation method and present the techniques to improve arc quenching performance.

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Design of MCCB Instant Trip Spring by 3D FEM Analysing (3D FEM 해석을 이용한 배선용 차단기의 순시트립부 설계)

  • Kang, Jong-Sung;Song, Hee-Chan;Choe, Jong-Woong
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.134-136
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    • 1998
  • When a MCCB Instant trip spring which is adjusted to notrip at -20% of each current from $5{\times}In$ to $10{\times}In$ and trip +20% of those is designed, we should know attraction force between Fixed Magnet and Armature. So we first made some samples, do experiments of weight, and simulated the modelling by 3D Maxwell S/W. With values of experiment and simulated values, we do design instant trip springs and repeat the above process. Finally we set up the Process of designing Instant spring. With it, we can save time and R&D cost.

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Researchs for the Development of MCCB adjustable Instant Trip Unit (배선용 차단기 순시 가조정 트립부 개발에 관한 연구)

  • Song, Jung-Chun;Ryu, Man-Jong;Kim, Kil-Soo;Kang, Jong-Sung
    • Proceedings of the KIEE Conference
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    • 1999.07a
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    • pp.354-356
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    • 1999
  • Through the Standard of MCCB, the Adjustable Type Instant Trip Unit should NO trip at -20% of each current from $5{\times}In$ to $10{\times}In$ and trip +20% of those. In this paper, we obtain the attraction force between Fixing Magnet and Moving Armature. So we first made some samples. do experiments of weight, and simulated the modelling by 3D Maxwell S/W. With values of experiment and simulated values, we do design instant trip springs by using the ADAMS S/W of kinematic simulation. Finally we product the 250A Adjustable Instant Trip Unit, and it is very useful to our customers.

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A Study on the Trip Time Sensitivity of MCCB Mechanism (배선용 차단기(MCCB) 개폐기구부의 트립시간 민감도에 관한 연구)

  • 엄위상;김길수;조현길;박진영
    • Proceedings of the KAIS Fall Conference
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    • 2000.10a
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    • pp.83-85
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    • 2000
  • 배선용 차단기의 개폐기구는 수동 조작력을 가동 접촉자에 전달하여 차단, 개폐의 동작을 행하는 것으로 Spring과 Link를 주체로 구성되어 있으며 기구부가 단락 차단 성능의 가장 큰 영향을 미친다. 제품 성능 개선을 위해 기구부를 변경하기 위해서는 많은 시행착오를 거치게 되는데 이 때 소요되는 시간과 비용을 줄이기 위해 동특성 해석이 널리 사용되고 있다. 본 논문에서는 제품의 동적 모델링을 위해 범용 동역학 해석 프로그램인 ADAMS(Automatic Dynamic Analysis of Mechanical System)을 이용하였고 설계 변경시 반복작업으로 인한 실패비용을 최소화하고 링크 지점의 최적값을 구하기 위해 민감도 해석과 최적화 기법을 도입하였다.

A Study on Failure Analysis of Low Voltage Breakers with Aging (경년열화에 따른 배선용 차단기류의 고장점 분석 연구)

  • Cho, Han-Goo;Lee, Un-Yong;Lee, You-Jung;Lee, Hae-Ki;Kang, Seong-Hwa
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.501-502
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    • 2006
  • In this paper, new and aging sample of MCCB and ELCB are investigated the main performance test such as short circuit test, mechanical and electrical endurance test, dielectric test and surge current test. The surface conditions of new and aging sample are analyzed by SEM, TGA and DSC. The ELCB occurred badness mainly in short circuit test and surge current test. The badness cause of short circuit test was confirmed due to imperfect contact of contact part.

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Operating Characteristics of Molded Case Circuit Breakers by Harmonic Currents (고조파 전류에 의한 배선용 차단기 동작 특성)

  • Jeon, Jeong-Chay;Yoo, Jae-Geun;Lee, Sang-Ick
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.2
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    • pp.68-74
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    • 2006
  • Malfunction and nuisance tripping of molded case circuit breaker(MCCB) caused by harmonic currents have been reported. But no data is available on the behavior of MCCB under harmonic currents. This paper tested the effects of harmonic currents on four common types of MCCB(thermal, thermal magnetic, magnetic and electronic types). Results of experiment detected no nuisance tripping with any of the breakers tested under test currents, included harmonic current, below rated currents. Additionally it was found that varying harmonic loading conditions did not affect manufacturer specified trip times for thermal only and thermal magnetic circuit breakers. However, under overloaded conditions, trip times of the magnetic only circuit breakers were gradually slowed according to increasing of harmonic currents, and it could cause hazardous overheating of cables. So, the use of magnetic only circuit breakers in the place harmonic currents we serious must be avoided.

A Study on the Characteristics Assessment and Fabrication of Distribution Board according to KEMC Standards (KEMC 규정에 의한 분전반의 제작 및 특성 평가에 관한 연구)

  • Lee, Byung-Seol;Choi, Chung-Seog
    • Fire Science and Engineering
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    • v.31 no.3
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    • pp.63-72
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    • 2017
  • This study fabricated a low-voltage 10 circuit distribution board based on the KEMC (Korea Electrical Manufacturers Cooperative) 2102-610 standard and performed a characteristics assessment of the developed 10 circuit distribution board to secure product stability. The developed 10 circuit distribution board is designed to have the characteristics of insulation materials, as well as resistance to corrosion ultraviolet radiation and mechanical impact. The developed distribution board is fabricated to have an appropriate protection class of enclosure, electric shock prevention and protection circuits, switchgear and its components, internal electrical circuits and connectors, external conduct terminal, insulation characteristics, temperature rise test, heat resistance, etc. The developed 10 circuit distribution board consists of a single phase circuit and 3-phase circuits. It is possible to measure in real time the leakage current generated from the load distribution line by installing a sensor module at the load side of each of the branched switchgears. In addition, it is possible to increase a circuit according to the use and purpose of the load and to also manage and check the load in real time. Temperature rise tests were performed on the developed 10 circuit distribution board at 18 places including the inlet connection, main circuit and distribution circuit bus bars and bus bar supports, etc. The highest temperature of $65.3^{\circ}C$ was measured at the R-Phase of the connection of the MCCB power supply for the branch circuit bus bar and a temperature rise of $61.6^{\circ}C$ was measured at the T-Phase of the load side. When applying thermal stress to an MCCB for 6 hours at $180^{\circ}C$ using a heat resistant experimental device, it was found that the actuator lever was transformed and moved in the tripped state.

Minimal Cut Set of Electric Power Installations using Fault Tree Analysis (FTA를 이용한 수변전설비의 최소절단집합 도출)

  • Park, Young-Ho;Kim, Doo-Hyun;Kim, Sung-Chul
    • Journal of the Korean Society of Safety
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    • v.32 no.1
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    • pp.41-46
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    • 2017
  • In this paper, from making an electrical fire which is thought to be the most damaging among potential dangers as a top event, minimal cut sets (MCS) about it were analyzed. For this, components of a power substation were classified into 15 items. Failure rates and modes were extracted based on Korea Electrical Safety Corporation, IEEE Gold Book, and RAC. To analyze the top event (an electrical fire), main events were assorted into "safety devices for overcurrent" and "ampere meter of detecter". Failure of components was divided into failure of VCB, COS, and MCCB. A fault tree was composed of 3 AND gate, 5 OR gates and 17 basic events. Overlapped events among the basic events are things which occur from relevant components. They were attached to the tree by distinguishing identifiers. In case of FT, two minimal cut sets of "IO_METER", "MF_METER", "DO_MCCB" and "IO_METER", "MF_METER", "DO_VCB" take 46% of electrical fires. Therefore, about basic events which are included in the top two minimum cut sets, strict control is necessary.

A Study on the Properties Analysis and Estimation of Odor Detection System (향 검지 시스템의 특성 해석 및 평가에 관한 연구)

  • Choi, Chung-Seog
    • Fire Science and Engineering
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    • v.23 no.2
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    • pp.1-5
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    • 2009
  • We studies wish to investigated establishment form of cabinet board, and confirm possibility of electrical disaster prevention through reappearance experiment of odor detection system. Established breaker consists of MCCB, RCD order in cabinet board for house, but industry is used together with. When imposed shock using shaker to terminal block that contact becomes in appropriate, flame was made sure. According to result that experiment attaching odor capsule in terminal block, capsule commissioned exactly by occurred heat. According to establishment position of sensor, difference of inspection time was about 10 seconds. Estimate odor inspection system by thing which electrical device accident prevention is available. When there is abnormal generated heat in connection of electric wire, accident prevention estimates that is possible by giving an alarm state of overheat to administrator.

The Causes and Analysis of Electrical Fires -focused on Dynamic Characteristics of RCD- (전기화재의 발생원인 및 분석 -누전차단기의 동작특성을 중심으로-)

  • 이상호
    • Fire Science and Engineering
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    • v.17 no.2
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    • pp.1-5
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    • 2003
  • Recently, the occurrences of electrical fire have been suppressed by a residual current protective devices(RCD), a molded case circuit breaker(MCCB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the RCD to break the circuit in the case of the conductor fractures, the failure of pressure contacts on connecting points and the momentary short circuit of low voltage wiring. Therefore, it is require to study the constructive problem of the RCD. In this paper, we have tested the operation characteristics of the RCD according to the R load and R-L load in the conductor fractures, the failure of pressure contacts on connecting points and the momentary short circuit of low voltage wiring.