GB435961A - Improvements in and relating to liquid break electric switches - Google Patents

Abstract

435,961. Oil-break switches. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London. Oct. 25, 1934, No. 30629. Convention date, Oct. 26, 1933. [Class 38 (v)] A liquid-break switch comprises a casing containing oil or other arc-extinguishing liquid in which are immersed relatively movable contacts responsive to variations in the pressure of the liquid, the casing having a flexible wall portion co-operating with means exterior of the casing for varying the pressure of the liquid to actuate the contacts. In the form shown, the movable contact structure comprises a number of sealed hollow expansible members 7 made of conducting material, such as copper, each member containing a compressible fluid such as air. The oil pressure within the tank 1 is varied by a flexible wall portion or metallic bellows 10 connected to an operating rod 11 which is latched against the tension of a spring 12 by a latch 13 which co-operates with a tripping solenoid 14. When the latch is tripped, the spring 12 acts on the bellows 10 to increase the pressure within the tank, with consequent collapse of the members 7, to produce a series of breaks between the fixed contacts 3, 4 and contacts 9 carried by the members 7. Return movement and latching of the rod 11 removes the pressure within the tank, whereupon the members 7 expand to close the circuit, the expansion being aided by springs 8. The lateral supports 15 for the fixed and movable contact members are connected by high resistances 17 which form a shunt across the breaks.