GB1293607A - Operating mechanism for a circuit interrupter - Google Patents

Abstract

1293607 Pneumatic actuation of switches; gas blast switches WESTINGHOUSE ELECTRIC CORP 19 Nov 1969 [10 Dec 1968] 56649/69 Heading H1N A gas blast switch is operated by a piston-andcylinder device in which the piston has a face 8b, permanently subject to a relatively lowpressure gas urging the piston towards the contacts closed position; a face 8c to which can be applied either low-pressure gas for closing the contacts or a high-pressure gas for opening the contacts; and portions 8d, 8x permanently subject to the high-pressure gas and giving as resultant force biasing the piston to the contact closed position. The device is housed in a metal enclosure mounted on an insulator 15 housing the switch (Figs. 7, 8, not shown). The enclosure is filled with low-pressure sulphur hexafluoride (SF 6 ). A changeover valve 36 controls the pressure applied to face 8c of the piston; the valve has spring-loaded seats 66, 67 and is operated by a long insulating rod 13 extending down through insulating pipes in the insulator 15. The rod 13 is held in tension by a bank of springs 31. Drainage pipes 69, 70 with suitable non-return valves convey any liquified SF 6 back to a main high-pressure reservoir where a heater vapourises it. The piston is coupled by rods 41, 62 to the movable switch contact and to an indicator flag 63, respectively. The switch is constructed and arranged substantially as described in Specification 1,293,369.