Abstract:

Miniature circuit breakers are generally short-circuit protected by magnetic tripping.Optimizing electromagnetic suction plays an important role in the design of miniature circuit breaker.The magnetic release model is established by using Creo software,and four kinds of moving iron core models with different structures and five kinds of yoke models with different structures are designed.The original model and optimization model are simulated and analyzed by using finite element software Ansys,and the electromagnetic suction and normalized acceleration of the moving iron core with different structures,different currents and different working clearances are obtained.The analysis results show that when the reduction volume of the moving iron core is small,or when the yoke length is shortened and the yoke thickness is increased,it is helpful to carry out the tripping action accurately and quickly.Finally,the instantaneous tripping experiments of three kinds of circuit breakers are carried out,and the experimental results are consistent with the simulation results,which verifies the correctness of the simulation results.

Key words: miniature circuit breaker (MCB), electromagnetic suction, moving iron core, yoke, tripping time