Abstract: A puffer-type interrupter for a circuit breaker has a stationary piston received in a movable cylinder which is connected to the movable contact of the interrupter, and which also carries a nozzle for producing a blast of gas through the separating contacts of the interrupter when the cylinder is moved over the piston. An auxiliary piston is slidably mounted relative to the main piston, and mechanism is provided to connect the two pistons together when the interrupter contacts are closed, and to connect the auxiliary piston to the movable cylinder after the contacts have separated.

Abstract: A metal ring adjacent the support insulator of a gas-insulated bus lines the interior of the outer grounded housing. The ring is formed to define at least a portion of a turn around the central bus so that, in the event of an arc from the central bus to the outer grounded housing, the arc root will fall on the interior of the metal ring and the arc current will create a magnetic field which will cause the arc root to rotate around the interior of the metal ring.

Abstract: A puffer interrupter has a bypass channel around the puffer piston, which channel is opened when the interrupter contacts have reached a separation greater than the maximum effective arc quenching separation.