Circuit breaker (current interrupter) for encased switching stations filled with an insulating gas

摘要

A circuit breaker for encased switching stations filled with an insulating gas has a main switching element and an auxiliary switching element (1, 3), between which a bellows (8) for producing a gas stream which cools the electric arc (16) is arranged. In a circuit-breaking process, the main switching element (1) first opens in the absence of current, gas is sucked into the bellows (8) and a coil spring (12) is tensioned. The auxiliary switching element (3) follows, after the releasing of a catch, under the effect of the coil spring (12), the switching arc (16) being ignited between the arc contact (17) in the nozzle (9) and the fixed arc contact (4). The gas stored in the bellows (8) flows through the nozzle (9) and blows very strongly on the electric arc (16), so that it is interrupted the next time the current passes through zero. The nozzle (9) has its orifice (24) at a distance (M) in front of the voltage-supply parts of the switching elements (1, 3) which is such that that no back-arcs can occur outside. The embodiment of the circuit breaker according to the invention makes do, on account of the chosen movement sequence of the switching elements (1, 3), with reduced driving force, although there is room for a relatively large bellows (8). The reduced volume requirement makes the circuit breaker highly suitable for incorporation in encased switching stations filled with SF6 or similar high-performance gases. <IMAGE>