双断点塑壳断路器触头终压力设计

新一代塑壳断路器（MCCB）采用电动斥力型旋转双断点触头结构，较传统单断点MCCB有更高的限流性能和分断能力。针对旋转双断点MCCB的结构特点，采用仿真与试验相结合的方法对MCCB触头终压力进行了设计与分析。利用有限元法与解析法分别计算触头洛伦兹力和霍尔姆力，获得触头所受电动斥力。基于触头电动斥力的计算，实现触头终压力的初步设计，并通过热一电耦合分析计算MCCB的稳态温升，对预设的触头终压力进行校核。

Design of Contact Pressure in Double-Break Moulded Case Circuit Breaker

As a result of the full use of electric repulsion force in the rotary double-break contact structure, the new generation of moulded case circuit breaker（MCCB） has obtained better current limiting performance and higher breaking capacity than that of a single break MCCB. For the structural characteristic of a double-break MCCB with a rotating contact arm, simulation and experiment were combined to design the contact pressure of the breaker. The preliminary design of contact pressure depends on the calculation of electric repulsion force of movable contact where FEM and analytical method were used respectively to calculate Lorentz force and Holm force. A thermal- electric analysis was performed for steady-state thermal analysis of MCCB, which could verify the preset contact pressure.