Operating Mechanism of Vacuum Circuit Breaker:

The lower end of the breaker is fixed to a spring-operated or solenoid operated mechanism so that the metallic bellows inside the chamber are moved upward and downward during closing and opening operations respectively. The contact movement should be such as to avoid bounce. It is noteworthy that the operating mechanism should provide sufficient pressure for a good connection between the contacts.

The pressure in a vacuum interrupter at the time of sealing off is kept about 10–6 torr. The interrupting rating is between 250 and 1,000 MVA. The normal current carrying capacity for a single interrupter is 800 – 3,000 A; 4.2 kV – 7.6 kV.