The vacuum circuit breaker is named after its arc extinguishing medium and the insulating medium of the contact gap after the arc extinguishing are high vacuum, which mainly includes three parts: vacuum interrupter, electromagnetic or spring operating mechanism, bracket and other components.

Vacuum circuit breakers use vacuum as the arc extinguishing and insulating medium. The parts are sealed in a shell made of insulating glass and other materials, and the sealing of the movable contact rod and the movable contact is realized by a metal bellows. Vacuum circuit breakers have the following characteristics:

(1) Lightweight structure. The contact opening distance is small (10kV, only 10mm), quick action, light operation, small size and light weight.

(2) The arcing time is short. Because the contact is in a vacuum, basically no arc occurs. Very small arcs can generally be extinguished in half a cycle (0.01s), so it is called a half-cycle circuit breaker, and the arcing time has nothing to do with the current.

(3) The recovery speed of contact gap medium is fast.

(4) Long life.

(5) The maintenance workload is small, and it can be fireproof and explosion-proof.