GB734088A - Improvements relating to liquid-immersed electric circuit breakers - Google Patents

Abstract

734,088. Fluid blast switches; switch contacts. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. April 17, 1953 [June 3, 1952], No. 13968/52. Class 38 (5). In a liquid-immersed switch, an arcing chamber 6<SP>1</SP> moves with and carries a spring- biased bridging contact member 5a which cooperates with fixed contacts 1a. The arcing chamber may be formed of two mating recessed apertured laminated insulating blocks held together by bolts 8 and a base member 11<SP>1</SP> of light alloy secured to the blocks by bolts 8<SP>1</SP>. As shown, the bridging contact member 5a is biased by springs 12a extending through apertures in a further bridging contact member 5b which is upwardly biased by springs 12b and co-operates with fixed arcing contacts 1b detachably secured to the fixed contacts 1a. When the switch is opened by downward movement of an actuating rod 16 the contacts remain in engagement until the moving assembly reaches the position in which the contact member 5a abuts a stop 14<SP>1</SP> and is separated from the fixed contacts 1a. The contact member 5b remains in engagement with the arcing contacts 1b until it abuts the contact member 5a. The contacts 5b, 1b then separate and the arcs drawn are extinguished by the arc-generated cross-blast exhausting through vents 9. In Figs. 1 and 2 (not shown), a single bridging contact co-operates with fixed contacts. In a modification, Figs. 5 and 6 (not shown), two bridging conductors extending side-by-side co-operate with a pair of fixed contacts and each bridging conductor consists of a pair of spring-biased finger contacts hinged together on a common fixed hinge pin. In a three-phase circuit breaker, Fig. 7 (not shown), the moving contact arcing-chamber assemblies are carried by a common moving cross-bar.