• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.227-227
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• 2009

To prevent such accidents, molded case circuit breakers with improved short-circuit current interrupting capacity are needed. This paper is focused on understanding the interrupting capability with respect to double contact structure and puffer assisted self quenching that are based on the shape of the contact system in the current molded case circuit breaker. The new arc quenching structure for increasing the interrupting capacity of molded case circuit breakers is investigated by simulation and experiment.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.926-928
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• 2002

Much progress has been made during the past two decades in numerical analysis of electromagnetic forces in molded case circuit breakers (MCCB) for increasing arc voltage due to the change of the configuration of arc chute and fixed conductor. A review on this topic is given. which mainly covers the past research activities associated with that of our company.

• 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.

• 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.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1536-1540
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• 1996

The Design of are quenching parts of molded case circuit breakers depends on the utilization of strength and distribution of the magnetic field by which the arc is forced. The magnetic field causes the are to move into a set of V-slotted iron grids, where the are is extinguished rapidly. This paper present the effective method 10 design V-slotted iron plates of the are breaking chamber of molded case circuit breakers. This magnetic force was calculated by using the flux densities in the arc which are obtained by three dimensional finite element method, as a result of that this paper verified by testing that a grid model which has biggest magnetic force is excellent in the are quenching ability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.394-394
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• 2009

Owing to the increasing number of intelligent homes(or called Smart home), the corresponding cost is much higher. Low voltage circuit breakers are widely used in the intelligent homes to interrupt fault current rapidly and to assure the reliability of the power supply. The distribution of magnetic field induced by arc current in the contact system of molded case circuit breaker(hereafter MCCB) depends on the shape, arrangement, and kinds of material of arc runner. This paper is focused on understanding the interrupting capability, more specifically of the arc runner, based on the shape of the contact system in the current MCCB. The magnetic driving force was calculated by using the flux densities induced by the arc current, which are obtained by three-dimensional finite element method. There is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by current and the flux density be present. This is paper present our computational analysis on contact system in MCCB.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.36-38
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• 2002

Low voltage circuit breakers which interrupt rapidly and raise the reliability of power supply are widly used in power distribution systems. In the paper, it was investigated how much Interrupting capability was improved by correcting the shape of the contact system in molded case circuit breaker(below MCCB), Prior to the interrupting testing, it was necessary for the optimum design to analyze magnetic forces on the contact system, generated by current and flux density. This paper presents both our compuational analysis and test results contact system in MCCB.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.8-13
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• 2015

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.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1994-1996
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• 2004

본 논문에서는 배전반 또는 분전반에서 널리 이용되고 있는 1000 V 이하의 배선용 차단기, 즉 MCCB(Molded Case Circuit Breakers)의 신뢰성을 평가하기 위한 시험계획 및 시험방법을 검토하기 위한 전단계에서 반드시 필요한 고장모드영향분석(FMEA)의 결과를 서술하고, 또한 고장모드별로 대응되는 스트레스를 이용한 신뢰성평가 방안에 대해서 제시한다.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.127-129
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• 2002

A new type of fiber-reinforced polymeric materials for the main body and the arc chamber of the low-voltage circuit breakers was developed. The tensile and the flectional strength of the three kinds of thermoplastic resins for the cover of MCCBs(Molded case circuit breakers) increase much higher than those made of BMC that has been used. In a high current-breaking test, an experimental MCCB with the new insulating material showed no-cracks on the bodies.