Analysis of axial magnetic field in vacuum interrupters of large current vacuum circuit breaker with dual-contact

A new type of “dual-contact” structure of vacuum interrupter is proposed in the paper. It consists of main contact and arc contact, which are used to break short circuit current and carry rated current, respectively. Using double-bellows, the contact bounce can be substantially reduced. In order to increase short circuit current breaking capacity of large-current vacuum interrupter, an optimal design of “iron magnetic ring” is put into arc contact to improve its magnetic performance. In terms of the new type large current vacuum interrupter, simulation results show that it is excellent in axial magnetic density and radial magnetic uniformity at current peak, and the contact area is effectively utilized.