The VBG-12F indoor high-voltage AC generator vacuum circuit breaker (hereinafter referred to as the generator circuit breaker) is an indoor switchgear component with a rated voltage of 12KV and three-phase AC 50Hz. The circuit breaker adopts an integrated design of the operating mechanism and the circuit breaker body, which can be installed in the KYN28A-12 central generator switchgear or in a fixed switchgear. Circuit breakers are used at the generator outlet as control and protection for the generator. The generator circuit breaker complies with the provisions of GB/T14824-2008 "High Voltage AC Generator Circuit Breaker" standard and has completed all type tests of the system source specified in the standard.