GB417866A - Improvements in and relating to electric circuit breakers - Google Patents

Abstract

417,866. Oil-break switches. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Spurgeon, S. J. ; 1429, 42nd Street, Birming- ham, Alabama, U.S.A.) April 12, 1933, No. 10953. Convention date, April 13, 1932. [Class 38 (v).] A liquid-break switch comprises relatively movable contacts forming two breaks in series, a casing 4 having a pressure chamber 20 communicating, through a restricted opening, with an outwardly flared exhaust passage 22, the arcs at the breaks being formed in the pressure chamber and passage respectively, and a plurality of insulating baffles 23 placed at the exhaust opening of the passage, the pressure generated by arcing within the pressure chamber 20 causing a blast of insulating liquid to pass through the passage and drive the other arc between the baffles. In one construction, Fig. 1, the fixed contacts 1, 2 are resiliently mounted with the aid of springs 12, 13 and are adapted to be connected by a hollow bridging contact member 3 which passes through apertures in the casing 4. The bridging member 3 is provided with pressure-equalizing apertures 24. For heavy currents, primary or main current carrying contacts are provided, in the form of a bridging member 25 and ring-shaped stationary contacts 26, 27 connected to the lead-in conductors at 28, 29, the main contacts being arranged to separate before the arcing contacts. In a modification, Fig. 2, the contact structure comprises a pair of arms 34, 35 pivoted at 36, 37 for jaw-like movement, and pairs of contacts 30, 31, 32, 33 carried by each arm and arranged to extend through apertures in the casing 4. The arm 35 is insulated from its pivot 37, and the arm 34 is connected to the lead-in conductor 8, the other lead-in conductor 9 being connected to the contact 30, which is insulated from the arm 34.