GB504305A - Improvements in or relating to compressed-gas operated electric switches - Google Patents

Abstract

504,305. Gas - blast switches. GENERAL ELECTRIC CO., Ltd., and GARRARD, C. C. Nov. 2, 1937, No. 29983. [Class 38 (v)] A compressed-gas operated electric circuitbreaker, in which the gas acts also to extinguish the arc formed between co-operating main contacts, has auxiliary isolating contacts in series with the main contacts, movement of a movable main contact to the circuit open position being arranged, after separation of the main contacts, to cause operation of the auxiliary contacts to the isolating position. When the circuit-breaker is to be opened the gas supply is connected to the main switch chamber 3 through aperture 10 by a solenoid operated valve (not shown). The movable contact rod 4, normally forced into engagement with the fixed nozzle shaped contact 1 by a spring 7, is thereby moved to the right by the gas pressure on a piston 5 secured to the contact rod 4, the arc being quenched by the gas blast through the nozzle contact and silencer 2 to atmosphere. As the moving contact 4 approaches its extreme open circuit position, an extension thereof, a rod 24, trips a spring-biassed pivotal catch 22 to release the pivotal moving contact 16 of the isolating switch 16, 18. A biassing device acting through a link 21 thereupon opens the isolating switch, and an auxiliary switch (not shown) controlled by the pivotal contact arm 16 de-energizes the solenoid actuated valve to stop the flow of pressure gas to the switch chamber 3. The spring 7 then closes the main contacts 1, 4. A spider 9 serves both to guide the main moving contact 4 and to connect it through the metallic portion 14 of the switch chamber to the fixed contact 18 of the isolating switch.