Research of Electro-dynamic Repulsion Force of Miniature Circuit Breaker Contact

Abstract

In the process of miniature circuit breaker's short circuit breaking, the short-circuit current will cause the electro-dynamic repulsion force between the pairs of contacts, thus there is a certain influence on the movement of operating mechanism. The electro-dynamic repulsion force is composed of the Lorentz force and the Holm force. In this paper, the electro-dynamic repulsion force of the contact is researched. The Holm force is calculated under different currents. Lorentz force under different contact gaps and different currents are simulated and analyzed. The results show that Holm force accounts for about 30% in electro-dynamic repulsion force, and Lorentz force accounts for about 70%. When contact gaps is 0mm, electro-dynamic repulsion force plays more important role in accelerating the contact breaking.