Damage Pattern and Operation Characteristics of a Thermal Magnetic Type MCCB according to Thermal Stress

Lee, Jae-Hyuk; Choi, Chung-Seog

doi:10.14346/jkosos.2013.28.3.069

Cited by 4 publications

(3 citation statements)

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“…MCCB 에 대한 연구는 저항 부하에서 MCCB 접속 단자부의 접 속 결함에 의한 화재 위험성 (9) , MCCB 및 단자대 접속부 의 접촉 불량에 의한 소손 특성 및 과열 감지 기법 (10) , MCCB의 트래킹에 의한 전기화재 사례 (11) (12) . (13) . 또한 PCITS로 과전류를 공급 하여 소손된 MCCB의 패턴과 특징이 상이하다는 것이 입 증된바 사고 원인의 규명 및 판정 등에 적용이 가능할 것 으로 사료된다 (13) .…”

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Carbonization Patten and Operation Characteristics of a 1Φ 2 W MCCB Damaged by PCITS

Lee¹,

Choi²

2014

Fire Science and Engineering

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The purpose of this study is to analyze the damage pattern when overcurrent is applied to a thermal magnetic type molded case circuit breaker (MCCB) using a Primary Current Injection Test System (PCITS). When an overcurrent of 150 A was applied to the PCITS for 5 seconds with the trip bar of an MCCB being damaged, it was found that the surface of the temperature control device (bimetallic strip) positioned at the right was significantly carbonized. When an overcurrent of 300 A was applied to the PCITS for 5 s under the same conditions, the entire temperature control device was deteriorated, becoming flattened and in close contact with the MCCB. When an overcurrent of 450 A was applied to the PCITS for 5 s, the coil of the temperature control device was melted and disconnected. In addition, it was observed that the contacts, the enclosure and upper cover were deformed and there was a trace of carbonization on them. When approximately 3 s had elapsed after an overcurrent of 600 A was applied, white smoke occurred inside the MCCB and a flame was radiated out, after which the overcurrent supply stopped with "phutt" (whomp) sound. It was observed that when the same type of MCCB is damaged by a general flame, the surfaces of its handle, terminal, arc divider (extinguisher) and temperature control device were carbonized uniformly. In addition, it was found that the trip bar of the operating mechanism was melted down and the metal operation pin was moved while being tripped.

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Section: 서 론unclassified

“…(13) . 또한 PCITS로 과전류를 공급 하여 소손된 MCCB의 패턴과 특징이 상이하다는 것이 입 증된바 사고 원인의 규명 및 판정 등에 적용이 가능할 것 으로 사료된다 (13) . …”

Section: 서 론unclassified

Carbonization Patten and Operation Characteristics of a 1Φ 2 W MCCB Damaged by PCITS

Lee¹,

Choi²

2014

Fire Science and Engineering

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“…. 단기(molded case circuit breake, MCCB) (9)(10)(11) 는 과전류에 의한 전기설비 사고를 보호하기 위한 기기이며 감전사고 및 전기화재 , 를 예방하는 기능은 없다 저압용 고감도형 누전차단기 .…”

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A Study on the Development of ETEC-IGR Test Devices for the Reliability Evaluation of RCD and ETEC-DPS

Kim¹,

Choi²

2023

Fire Sci. Eng.

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In this study, ETEC-IGR was developed in order to test the residual current protective device (RCD) and electric fire prevention system (ETEC-DPS) used in low-pressure electrical facilities. Furthermore, the reliability of the developed product was verified with Minitab PGM. The ETEC-IGR was designed to supply single-phase two-wire power and was equipped with an insulation transformer to protect against surge voltages and ground defects during testing. The results revealed that the load current (IL) may linearly flow from 0 A to 50 A, and the leakage current (IG) and the leakage current of the resistance component (IGR) may vary from 0.0 mA to 30 mA. Furthermore, the standby power was 98.43 W when the developed ETEC-IGR and the ETEC-DPS were connected. Moreover, the standby power was analyzed as 97.59 W when only the developed ETEC-IGR was connected. In addition, the standby power of the ETEC-DPS was interpreted as 0.84 W, and it was judged that the characteristics of the developed product were excellent. In addition, the heat dissipation environment, noise level, winding resistance, insulation resistance, voltage fluctuation rate, and AC/DC withstand voltage test of the developed test device met the relevant regulations. The normal distribution analysis of the developed ETEC-IGR revealed that the standard deviation was 0.3209, AD was 0.520, and P was 0.171. Thus, the data were interpreted as appropriate. In addition, the measured data were found to be more than 95% reliable, and the error was also less than 1 W. Furthermore, the reliability was verified with the 95% confidence interval in the box plot and histogram analysis.

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Comparison of Standards for a 1ϕ 2 W MCCB and Study on the Evaluation of Heat Resistance Characteristics

Choi¹,

Lee²

2014

Fire Science and Engineering

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This study obtained the following results by analyzing the standards related to a 1φ 2W MCCB and evaluating its heat resistance characteristics. Since KS C 8321 corresponds to IEC 60947-2 standards, most of the related regulations are similar. The NFPA, which presents the user oriented safety regulations, contains no details about tests or inspections, etc., but it does specify in detail the regulations directly related to safety. It can be seen that KS C 8321 classifies in detail the items about tests and inspections. However, IEC 60947-2 and IEEE C37.51 simplified the test and inspection items or omitted some of them. When applying thermal stress to an MCCB for 6 hours at 180

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Damage Pattern and Operation Characteristics of a Thermal Magnetic Type MCCB according to Thermal Stress

Cited by 4 publications

References 0 publications

Carbonization Patten and Operation Characteristics of a 1Φ 2 W MCCB Damaged by PCITS

Carbonization Patten and Operation Characteristics of a 1Φ 2 W MCCB Damaged by PCITS

A Study on the Development of ETEC-IGR Test Devices for the Reliability Evaluation of RCD and ETEC-DPS

Comparison of Standards for a 1ϕ 2 W MCCB and Study on the Evaluation of Heat Resistance Characteristics

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