With the development of the electric industry and the rapid increasing of the wastage of the power , the effect of the low - voltage circuit breaker on the power supply and the circuit protection is more and more important . it was required that the circuit breaker has enough short circuit breaking capacity and some intelligent functions 随着我国电力工业的发展和用电量的猛增，低压断路器在配电和保护线路中起着日益重要的作用，要求它具备很大的短路电流分断能力，实现选择性保护和供电安全，同时具有一定的智能化功能。
After the axial magnetism field of the vacuum interrupter is put into the iron core , the iron core makes the axial magnetic field distribute more uniform in the radial . the more uniform the axial magnetic field is distributed , the more uniform the vacuum arc is distributed on the surface of electrode . in the course of making , erosion on the surface of electrode is more uniform as well , so it is good for improving the breaking capacity of vacuum interrupt 在杯状纵磁真空灭弧室中加入铁芯后,铁芯使纵向磁场在径向的分布更均匀,这样可使真空电弧在电极表面上分布更为均匀;在开断过程中,电极表面的烧蚀也越均匀,有利于真空灭弧室开断能力的提高。
