GB660944A - Improvements in or relating to gas blast electric circuit breakers - Google Patents

Abstract

660,944. Gas-blast switches. AKT.-GES., BROWN, BOVERI, & CIE. June 23, ] 949. [July 23, 1948]. No. 16735/49. Class 38 (v). In a gas-blast circuit-breaker, a resistance h is connected by a normally open auxiliary switch i across the interrupting contacts a, b, the movable auxiliary contact being connected to a piston n slidable in a cylinder o and subjected to the circuit-breaker pressure gas through a pipe m. On opening the blast valve f, the contacts a, b separate, the piston n rises closing the auxiliary switch i, and a port p in the cylinder is exposed to the pressure gas which flows round the outside of the cylinder and through an opening in the top thereof, thus equalising the pressure on both sides of the piston n and permitting a spring r to re-open the switch i and disconnect the resistance h. The time for which the switch i is closed is variable by adjusting the size and arrangement of the port p. In breakers where the gas pressure is maintained in the switch chamber 'for voltage isolation, a non-return valve q controlling an opening in the cylinder o beneath the piston is opened, when the blast valve f, having a pressure-discharge opening in the closed position, is operated to close the breaker. The switch i and resistance h, instead of being housed in a common insulator k as shown, may be housed in separate insulators, or they may be separated by a partition in the insulator k (Fig. 2, not shown). Further, the insulators c, k, may lie at an angle to each other. The invention may be applied to a multiple break circuit breaker.