• Title/Summary/Keyword: low-voltage circuit breaker

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A Study of the Pre-Resistance Effects on the Optimization For Performance of the Ignition System with the Breaker Point Type (Breaker Point 型 점火裝置 性能 을 極大化하기 위한 Pre - Resistance 효果 에 對한 硏究)

  • 손병진;신영철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.2
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    • pp.133-139
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    • 1982
  • One of factors that affect combustion in the cylinder of the engine is to keep a greater energy in the ignition system to minimize pollutant emissions and to increase its performance of the low temperature. This paper reviews theoretically the state and input variables of the ignition system from the state transition equation. Effects on characteristics of the system such as primary current, secondary available voltage and spark duration by reducing the pre-resistance from 3.5 to 0 ohm in 12V system is experimentally investigated when the ignition coil has a primary resistance of 1.5 ohms ad the dwell angle of the breaker point is 43.2 degrees (0.75 radian). Advantages and limitations for using the low resistance of the primary circuit are also presented to optimize the performance of the ignition system with the breaker point.

Electrical fire hazards in the domestic circuit protected by Electric Leakage circuit Breaker(ELB) (누전차단기가 설치된 옥내전로에서의 화재위험성)

  • 홍성호;김두현;김상철;김상렬
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 1998.11a
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    • pp.335-340
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    • 1998
  • This paper presents a study on the electrical fire hazards of leakage current in a distribution circuit simulating a domestic circuit for low voltage. In this simulated circuits, total charges and energy of leakage current are calculated by a theoretical approach and compared with the results obtained from experiments, The approach and results become a cornerstone for studying and analyzing causes of electrical fires.

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Development of 460V/225A/50㎄ Contact System in Current Limiting Molded Case Circuit Breakers

  • Park, Young-Kil;Park, Chan-Kyo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.3B no.4
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    • pp.165-172
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    • 2003
  • Low voltage circuit breakers are widely used in power distribution systems to interrupt fault current rapidly and to assure the reliability of the power supply. This paper is focused on understanding the interrupting capability, more specifically of the contacts and the arc runner, based on the shape of the contact system in the current molded case circuit breaker (hereafter MCCB). Moreover, in order to improve the interrupting capability of the circuit breaker, the estimation and analysis of the interrupting capability, based on the 3-D magnetic flux analysis, were developed. Furthermore, this paper also presents results of the estimation and analysis of the interrupting capability when applied to different model breakers. In addition, this paper analyzes the efficiency of the interrupting tests by forming false current paths consisting of a three-division cascade arc runner in the contact system. With regards to the interrupting test, there is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by the current and flux density be present. Based on the results of this study, this paper presents both computational analysis and test results for the newly developed MCCB 460V/225A/50㎄ contact system.

A study on AC over-current breaker using thyristor (Thyristor를 이용한 교류과전류 차단에 관한 연구)

  • 박민호;심재명
    • 전기의세계
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    • v.28 no.7
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    • pp.49-55
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    • 1979
  • This paper describes the mechanisms which breaks A.C. over-current protection in low voltage load. For the high speed over-current protection, it consists of thyristor switching circuit by forced commutation, IC logic gate controlled circuit and over-current detector with reed switch. Under various duty conditions, breacker was carried out several experiments and discussions. The results are as follows; (1) over-current cut off is possible within a quarter cycle (4ms at 60Hz) and clear is at least ten times faster than its electromechanical equivalent. (2) as the forced commutation thyristor circuit breaker has capability of high speed break, equivalent surgy current capacity of switching thyristor is increased more than twenty times of its rated current. (3) breaker using solid state dose not produce any harmful arc during switching period. Therefore the breaker above described may be considered an effective over-current protector for soli state power devices in industrial applications.

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A Study on the High Speed Breaking of Parallel Arcing (병렬아크의 고속 차단에 관한 연구)

  • Kim, Il-Kwon;Ji, Hong-Keun;Kim, Sung-Uk;Park, Dae-Won;Kil, Gyung-Suk
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.327-331
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    • 2008
  • This paper dealt with high speed breaking method to parallel arcing in low-voltage systems. The proposed high speed breaking circuit consists of a Rogowski coil and an integrator, and operates with an earth leakage circuit breaker (ELCB). A parallel arcing state was simulated by a short circuit using stripped wires. In this test, we analyzed tripping characteristics of the circuit breaker by the length of wires from 5m to 30m. From the experimental results, we confirmed that the proposed method can break the parallel arcing within a few millisecond.

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The Comparison and Analysis about Earth System based on IEC60364 (IEC 60364 기반 접지계통 비교 분석)

  • Jung, Jin-Soo;Han, Woon-Ki;Kim, Oh-Hwan;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.1
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    • pp.56-62
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    • 2010
  • This paper describes the analysis of loop impedance characteristics by impedance alteration of protective conductors and operating characteristics of electric leakage circuit breaker by each earth systems(TT system, TN-S system and TN-C system) in IEC 60364. As a result, loop Impedance was affected by resistance & inductance. The current& voltage characteristics about earth system were identified that the TN-S system was high fault current & low touch voltage. TN-C system was almost same the TN-S system but TT system was low fault current & high touch voltage.

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.

Design of an Arc Current Controller for Arc Interruption

  • Kang, Chang-Soo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.9
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    • pp.109-113
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    • 2007
  • In this paper, an arc current controller was designed for the interruption of arc fault currents occurred in a low voltage network. Arc in an electrical network represents the characteristics of low current, high impedance, and high frequency. Conventional controllers do not have arc current interrupt functions. Thus, an arc current controller was designed for the interruption of arc fault currents.

Analysis of Effect on Personnel Computer in case of turning off Power supply of Circuit Breaker for Low Voltage (저압용차단기 전원 개폐시 개인용 PC에 미치는 영향 분석)

  • Gil, Hyoung-Jun;Shong, Kil-Mok;Kim, Young-Seok;Kim, Chong-Min
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.12
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    • pp.124-129
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    • 2014
  • This paper describes the analysis of the effect on personnel computer in case of turning off power supply of main breaker in general electrical installation. In order to analyze the effect on personnel computer in case of turning off the power supply of main breaker, the switching impulse generator has been designed and fabricated which makes it possible to evaluate the effect on electrical product by switching impulse. The switching impulse tests were carried out for personnel computer according to applied voltage and number of switching impulse. As a consequence, switching impulse had not a significant influence on personnel computer in this study. The varistor of power input section functions as a protection of switching impulse as well as lightning impulse. The results will be used to related organization, and electrical product manufacturer, and residents.

Study on Measurement Method of Dielectric Recovery Voltage to analysis Dielectric Recovery Characteristic of Molded Case Circuit Breaker (저압 배선용차단기 절연회복특성 파악을 위한 절연회복전압 측정기법 연구)

  • Song, Tae-Hun;Cho, Young-Maan;Ko, Kwang-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.8
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    • pp.49-54
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    • 2015
  • Molded Circucit Breaker(MCCB) is a most widely used device to protect loads from the over-current in low power level distribution system. When the MCCB interrupts the over-current, the arc discharge occurred between fixed contact and moving contact to create hot gas. By the Lorentz force due to arc current, the occurred arc is bent to the grids. The grids extend and cool and divide it for arc extinguish. In the majority cases, the MCCB protects loads by interrupting the over-current successfully but in some cases the re-ignition is occurred by hot-gas created during process of interruption. The re-ignition arises when the recovery voltage(RV) is more higher than the recovery strength between contacts and it leads to interruption fault. Therefore to find out the dielectric recovery characteristics of protecting device has a great importance for preventing interruption fault. In this paper, we studies measurement method of the dielectric recovery characteristics considering inherent attribute of the MCCB. To measure the dielectric recovery characteristic of MCCB, we makes an experiment circuit for applying the over-current and the randomly recovery voltage. The measurement methode to find out the dielectric recovery voltage of the MCCB was established and the result was based on experiment results.