GB599318A - Improvements in or relating to liquid-blast electric circuit interrupters - Google Patents

Abstract

599,318. Liquid-blast switches. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Aug. 31, 1945, No. 22460. Convention date, Aug. 31, 1944. [Class 38(v)] A liquid-blast circuit-breaker in which a pressure-generating arc forces extinguishing fluid through an interrupting arc has two mechanically driven pistons to supplement the normal flow, one jetting fluid into the pressure generating arc and the other which may be stalled by back-pressure during high current interruption, but subsequently flushes out the interrupting arc. The circuitbreaker comprises two arc - extinguishing units, of laminated construction mounted on the terminal stems of insulators in an oil tank, Fig. 1 (not shown), each housing the pressure-generating contact 16, intermediate contact 17, and an interrupting contact 47, connected through isolating contact 62 by a bridging piece 12 to the other unit. A spring-loaded insulating rod 31 abutting on the bridgepiece carries a pin 29 engaging one arm 27 of a forked lever, whose other arm engages a pin 22 to impart linear motion to the pressure-contact 16, along its guide pin 20. The rod 31 also drives the piston 37 to force oil through passages 41 into the pressurearc chamber when the breaker is opened. A vent passage from the top of the pistonchamber into the unit equalises the arcpressure on both sides of piston 37 so that no extra force is required to open the contacts with high arcing currents. The other spring-loaded piston 49 is slidably mounted on the interrupting-contact 47 and vented on its upper side to the tank so that on high currents it is held up by the internal pressure but subsequently forces oil through passages 55, 45 to the interrupting arc. Check valves 56, 57 ensure a supply of clean oil being drawn into the arcing unit from the tank when the circuit-breaker is reclosed. Specification 578,422 is referred to. The Specification as open 'to inspection under Sect. 91 also refers to Specification 600,733. This reference does not appear in the Specification as accepted.