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A Study on the Operating Characteristics of Molded Case Circuit Breakers according to Temperature Rise
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 Title & Authors
A Study on the Operating Characteristics of Molded Case Circuit Breakers according to Temperature Rise
Jung, Da-Woon; Kim, Jae-Ho;
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 Abstract
Molded Case Circuit Breakers (MCCBs) are typically used to provide over current protection for electrical safety caused by short circuit faults and overloads in indoor low voltage power systems. The MCCB automatically connects and disconnects loads from the electrical source when the current reaches a value and duration that will cause an excessive. However, the MCCB sometimes is not interrupted due to a malfunction, nuisance tripping, or in a fire. Ensuring electrical safety is very important in a indoor low voltage power system. This paper presents the operating characteristics of MCCBs according to a temperature rise from room temperature to 160 degrees Celsius delivered by a radiant panel heater. The ABS 54c(rated current: 30A) of the hydraulic magnetic trip type was used in the experiments. The signals of temperature, voltage, and current were measured using the high accuracy Signal Conditioning Extensions for Instrumentation (SCXI) measurement system with the LabVIEW program manufactured by National Instruments. The operating characteristics were measured as functions of current amplitude and ramp-up rate. The MCCB tripping time decreased as a result of increasing current amplitude and ramp-up rate under a temperature rise condition, because the temperature and level of the current are directly proportional to the tripping time. Additionally, an instantaneous operation was observed after 8 times of the rated current, and the MCCB began to melt a surface temperature of around 300 degrees Celsius of. The experimental results coincided well with the operating curve.
 Keywords
molded case circuit breakers;mccb;short circuit;over load;fault;
 Language
Korean
 Cited by
1.
고조파 전류에 따른 완전전자식 배선용 차단기의 동작특성에 관한 고찰,정다운;김재호;

조명전기설비학회논문지, 2016. vol.30. 4, pp.31-36 crossref(new window)
 References
1.
Korean Agency for Technology and Standards, "KS C 8321", 2012.

2.
Korean Agency for Technology and Standards, "KS C IEC 60947-2", 2012.

3.
S. H. Lee, "Fire Investigation Theory and Practice", Dong Hwa Publication Ltd., pp. 87-102, 2012.

4.
D. W. Jung, B. J. Kim and J. H. Kim, "Operating Characteristics of Molded Case Circuit Breakers according to Temperature", Spring Conference of Korean Institute of Illuminating and Electrical Installation Engineers, pp. 30, 2015.

5.
J. G. Yoo, S. I. Lee and J. C. Jeon, "Survey on the Malfunction of MCCB and ELB in Private Electrical Facilities", Journal of the Korean Institute of Illuminating and Electrical Installation Engineers, Vol. 19, No.2, pp. 87-93, 2005.

6.
S. Y. Kim, "An Analysis of MCCB's Abnormal Operation Characteristic in the Nuclear Power Plant", Master's Thesis, Department of Electrical Engineering, Graduate School Chungnam National University, Daejeon, Korea, 2009.