GB1295557A - - Google Patents

Abstract

1295557 Gas blast circuit breakers BROWN BOVERI & CO Ltd 28 May 1971 [7 Aug 1970] 18052/71 Heading H1N A gas blast circuit breaker has a main movable contact 11 and an arcing nozzle contact 10 both of which are pneumatically actuated by respective piston and cylinder arrangements. In the closed position, see Fig. 1, the opening of blast valve 9 enables the gas blast to pass from the high pressure chamber 8 through port 16a in fixed cylinder 16 and port 15a in movable cylinder 15 to move the main contact 11 by means of the piston-like projection on cylinder 12. The high pressure blast passing through port 12a, open due to the spring biased position of valve 13, maintains the position of the piston 10a and hence the contact 10, while the main contacts open. The piston 10a then moves with the cylinder 12 and cylinder 15 to the contact open position, a damping of the movement being provided between the lower surfaces of cylinder 15 and the cylinder 16. In the open position, Fig. 3 (not shown), the valve 13 blocks port 12a whilst allowing the high pressure gas, when valve 9 opens, to pass through ports 12b, 13a to the lower surface of piston 10a to close the nozzle contacts 5, 10. The high pressure gas, due to the alignment of parts 16b, (15c) also raises cylinder 12 and subsequently cylinder 15, back to the breaker closed position.