Abstract: A high-voltage power circuit breaker contains a plurality of phases which are contained in respective separate tanks which may be filled with sulfur hexafluoride. Each phase contains a respective trip-free contact operating mechanism connected to the interrupter contacts within the tank. Each of the trip-free operating mechanisms are closed simultaneously by a pneumatic closing mechanism contained in only one of the poles and connected to the other pole operating mechanisms by a common operating rod. Each of the poles are simultaneously closed by the pneumatic operating mechanism, and each pole can open independently of the other poles through its own trip-free operating mechanism.

Abstract: A stationary contact structure for a gas blast circuit interrupter consists of a conductive hollow cylinder which is slotted to define contact fingers, and the ends of the contact fingers are inwardly deformed so that the ends of the fingers closely abut one another to prevent inward deflection of the contact fingers to a degree which would exceed their elastic limit.