Miniature Circuit Breaker Contact Dynamic Simulation And Analysis

Although miniature circuit breaker (MCB) is compact and simple, the internal structure andworking principle are quite complex. Especially in the short circuit breaking process, itsmovement relates to electromagnetic drive and linkage mechanical operation. The study on theminiature circuit breaker’s short circuit breaking process is important to improve its reliability.The electro-dynamic repulsion force of the contact is researched. The calculation method ofthe Holm force is confirmed and it is calculated under different currents. The simulation methodof the Lorentz force is researched and it is generated on the static and dynamic conductive rod.Lorentz force under different contact spacing and different currents are simulated and analyzed.The proportion of Holm force and Lorentz force in electric-dynamic repulsion is researched andwhich part has greater effect on the accelerating contact breaking process is confirmed.The study on the static and dynamic characteristics of the miniature circuit breaker’selectromagnetic tripping mechanism is done. The electromagnetic tripping model is established.Then, the material properties and mesh are set. Finally, the short-circuit current is used as theincentive to simulate the static electromagnetic force and the moving core’s dynamiccharacteristics of the electromagnetic tripper.The solid model of the operating mechanism, contact system and electromagnetic tripperare established and assembled. The electromagnetic force and contact electro-dynamic repulsionforce are used as the electromagnetic drive force. When the miniature circuit breaker carriesdifferent currents, contact’s displacement characteristics and speed characteristics are researchedThe finite element analysis software Ansoft is used to simulate and analyze the contact’selectro-dynamic repulsion force and the electromagnetic tripper’s electromagnetic force, in orderto simplify the complex electromagnetic calculation problems. The dynamic simulation analysissoftware ADAMS is utilized to do dynamic analyses, which can reduce the difficulty ofestablishing dynamic equations and makes the movement process visual, intuitive and simple.