A high-power cathode circuit breaker

RECENT INCREASES in the size of d-c systems fed by mercury-arc rectifiers have created a need for a faster, higher capacity cathode circuit breaker. These high power d-c systems have many rectifiers in parallel and are subject to a fault condition peculiar to mercury-arc rectifiers, known as arc back. If there were no protective device in the circuit, these arc-back currents would ultimately reach a size much beyond that which might be tolerated. Mechanical stresses and overheating would damage the equipment.