GB643218A - Improvements relating to spring-operated electric circuit-breakers - Google Patents

Abstract

643,218. Automatic circuit - breakers. REYROLLE & CO., Ltd., A., and ALLAN, A. May 20, 1948, No. 13631. -[Class 38(v)] In a spring-operated circuit-breaker particularly of the auto-reclosing type, an explosive charge is utilized to stress the operating spring which provides energy for both the closing and opening movements. The circuit-breaker has an operating linkage such as described in Specification 582,643, and is shown in Fig. 3 in its normal closed position in which the operating spring 10 is partly stressed. When a tripping catch 20 is released, the tension of the spring 10 pulls down the end 18 of a lever 17, which is pivoted at its mid-point 21 to a contact operating lever 22 pivoted at a fixed point 23. The other end 16 of the lever 17 which is pivoted to a main link 15, is prevented from moving upwards by a piston 27 on the link 15 being at the limit of its travel in a cylinder 28, so that the downward movement of the end 18 brings the mechanism into the position shown in Fig. 1 with the contacts 25 open. This opening movement causes the firing of a cartridge in the firing mechanism 30 by means of a time lag device 29, so that a brief interval after the opening of the contacts, the firing of a cartridge causes gases to enter the cylinder 28 through a port 31 to force down the piston 27. The resulting downward movement of the link 15, causes a lower lever 12 to pivot about a fixed axis 13 to stretch the spring 10; the movement of the link 15 also causes the lever 17 to pivot about its pivot 21 also to stretch the spring and to reset the catch 20. The mechanism has now reached a position in which the spring 10 is fully stressed and the piston 27 is at the bottom of its stroke where it uncovers a port 32. The pressure in the cylinder is released and the spring 10 moves the link 15 and piston 27 back, reclosing contacts 25 at the same time, the mechanism moving back into the position of Fig. 3. The provision of a cartridge magazine with suitable automatic ejecting and reloading mechanism, enables further reclosing of the circuit-breaker if tripped again due to the persistence of a fault, in which case the number of automatic reclosing operations is determined by the number of cartridges in the magazine.