Contact Failure Analysis and Optimization Design of Molded Case Circuit Breaker

doi:10.16628/j.cnki.2095-8188.2025.07.007

Abstract

Abstract:

A short-circuit overload test under an effective current of 8 000 A is conducted on a certain double-break moulded case circuit breaker (MCCB),and the contact ablation fault that occurred is analyzed. First, a theoretical calculation of the electric force is performed. Then, using Maxwell 3D finite element analysis software combined with the Holm force calculation formula,the electric repulsion of the double-break MCCB is calculated. The trends of the two calculation results are consistent, and the cause of contact ablation is determined through comparison.The error between the simulation calculation result and the measured value of contact pressure does not exceed 8%,and the used calculation method can provide a reference for the design and optimization of the MCCB contact system.

Key words: molded case circuit breaker (MCCB), finite element analysis, electrodynamic force, electromagnetic repulsion force, contact

CLC Number:

TM561

LIU Haibin, XIANG Xiaoqing, ZHOU Mingming. Contact Failure Analysis and Optimization Design of Molded Case Circuit Breaker[J]. LOW VOLTAGE APPARATUS, 2025, 0(7): 44-48.

Figures/Tables 10

References 8

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材料名称	相对磁导率	电导率/ (S·m^-1)	密度/ (kg·m^-3)
铜	0.999 991	58 000 000	8 933
银	0.999 980	61 000 000	10 500
冷轧钢板08F	相关B-H曲线	2 000 000	7 872

名称	A相	B相	C相
洛伦兹力	89.63	90.50	90.04
单触头洛伦兹力	44.82	45.25	45.02

名称	A相	B相	C相
单触头洛伦兹力	44.82	45.25	45.02
Holm力	39.50	40.60	39.90
总电动斥力	84.32	85.25	84.92
实测触头压力	78.50	79.00	79.00

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