GB499664A - Improvements in electric circuit breakers having arc control arrangements - Google Patents

Abstract

499,664. Liquid-blast switches. UPTON, A., PAILIN, G., and FERGUSON PAILIN, Ltd. July 26, 1937, No. 20636. [Class 38 (v)] A circuit-breaker having arc control by means of cross-jet type explosion pots has a tubular moving contact rod which is provided remote from its contacting end and outside the main passage, with one or more valved ports arranged to open, such as against the bias of a spring, when and only when, due to interrupting unduly large powers, the arcpressure generated in the pot is greater than arises when interrupting powers for which the arc control means is otherwise ordinarily designed. The valve may be arranged to open quickly initially and then against, for example, a dashpot. The fixed contact 1 is slidable in a metal tube 6 screwed into a metal drum 5 closing the end of the explosion pot 4. The explosion chamber 3 communicates through passage 12 with a transverse passage 13, which provides the cross-jet of oil or other liquid and is fitted with arc splitters 14. The hollow movable contact 2 screws into a tubular member 16 having one or more radial ports 17, and a piston 19 having a stop (not shown) at its left-hand end, is normally urged by a spring 21 into a position in which the ports are closed, the piston being operable by excessive pressure when large powers are being opened. Alternatively a hinged-plate or clappertype valve may be employed on the cylindrical exterior or extreme end of the movable contact, or on its supporting bar, and closure of the valve may be controlled by a dash-pot.