GB404857A - Improvements in and relating to liquid blast electric circuit breakers - Google Patents

Abstract

404,857. Oil-break switches. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Paul, W. E. ; 2279, Grand Boulevard, Schenectady, New York, U.S.A.) May 19, 1933, No. 14588. Convention date, May 20, 1932. [Class 38 (v).] An oil-, or other insulating liquid, blast circuit-breaker comprises an explosion chamber consisting of a metal cup 6 containing a two-piece insulating cylinder 7 spaced from it to form a pressurechamber 8. A central bore 9 leads to three radial exhaust passages 10 having inlets 101 for the movable contacts, and the whole is surrounded by an insulator 11. A fixed contact 13 on the cup 6 coacts with a contact 14 in the cylinder 7, the contact 14 being continued downwards to form a second contact 16. Further contacts 19, 20 are located in the cylinder 7 and interconnected by a strap 25 in a slot 25<1>. The contacts 16, 19, 20 are biassed downwardly by springs into engagement, in the closed position, with contacts 17, 18, 21 at one end of the bridge-member 2, the circuit between the cup 6 and member 2 being by way of contacts 13, 14, 16, 17, conductor 24, contacts 18, 19, strap 25, contacts 20, 21, and conductor 26. When the member 2 is lowered, an arc is struck between 13, 14, and the pressure generated in chamber 8 sends a stream of oil through passage 9 and across the arcs formed in the passages 10 by the subsequent separation of the contact-pairs 16-17, 18-19, 20-21, which are in series with one another and separate simultaneously. A vent 8<1> allows the pot to refill with oil. Magnetic blow-outs.-The blow-out action is facilitated by the action of the conducting loop formed by the contacts acting on the arcs electrodynamically.