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.

The empty circuit breaker has the following characteristics:

1. Lightweight structure, small contact distance (10 kV, only 10 mm), rapid 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 generally only need half a cycle (0.01 seconds) to extinguish, so it is called a half-cycle circuit breaker, and is related to current The size is irrelevant.
3. The recovery speed of contact gap medium is fast.
4. Long service life.
5. The maintenance workload is small, and it is fireproof and explosion-proof.

The main characteristics of vacuum circuit breakers are: short contact distance, small size, light weight, small operating power, fast action, fire and explosion protection; short arcing time (usually only half a cycle), and the size of the breaking current Irrelevant; After the arc is extinguished, the contact gap medium recovers quickly, and the breaking performance is good; the contact burns slightly when the current is interrupted, and the service life is long; the operating noise is small; suitable for frequent operation, especially suitable for breaking Capacitive load current (10kV and below).