GB905772A - Electric circuit breaker - Google Patents

Abstract

905,772. Automatic circuit-breakers. WESTINGHOUSE ELECTRIC CORPORATION. Oct. 10, 1960 [Nov. 3, 1959], No. 34697/60. Class 38 (5). [Also in Group XXXVI] In an automatic circuit-breaker the movable parts are mounted on projections of a single flat metallic plate. As shown in Figs. 1 and 3, the plate 25 has surfaces 55 against which are urged arcuate trunnions 51 of an insulating dolly 47 having a slot 45 in which a pin 43 of the moving contact member 41 engages. A snapaction spring 88 extends between a hole 89 in the member 41 and a projection 93 on a trip member 79 pivotally supported on an insulating plate 65 in slots 69, 71 in the frame 25. The end 82 of the member 79 is latched by a U-shaped magnetic member 85 carried on a bimetal 97 secured with connector 99 to a projection 101 of the frame 25. The insulating parts 65 and 47 ensure that the current passes from the moving contact member 41 through a flexible connector 95 and along the bimetal 97 to the connector 99 and terminal 100. The U-shaped magnetic member 85 co-operates with a magnetic projection 117 of the frame 25 to release the trip member 79 on overload above a predetermined value. An ambient temperature compensating bimetal 127 is attached to a projection 131 of the frame 25 and has an insulating pad 129 which bears on the bimetal 97. The tripping device is set during manufacture by supporting the frame with its associated parts in a special calibrating block (not shown) and driving a tapered pin through an opening 133 in the frame 25. Projections 137, 139 of the housing 13 locate the frame 25 and the projection 139 also helps to maintain the spacing between member 79 and the frame 25. A slot 49 in the dolly 47 prevents lateral movement of member 41. The trip member 79 has a projection 123 which can strike the member 41 if the contacts weld during tripping and the dolly 47 has a projection 121 which engages the projection 93 of the member 79 to stop the dolly in an intermediate position to indicate automatic tripping. On subsequent manual movement of the dolly to the off position the trip member 79 is reset by the projection 121. As shown in Fig. 4, a housing 13 may complete the enclosure of an adjacent circuit-breaker 11 so that an end cover 15 is only required for the right-hand circuit-breaker. Fixed contact carrying members 31 are located in the housings 13 by L- shaped portions 33 and are arranged (Fig. 4) to receive a single plug connector for two circuitbreakers. The ambient temperature compensating member 127 may be omitted if the compensation is achieved by making the relative temperature coefficients of the frame 25 and trip member 27 such as to maintain the relative latching positions of the bimetal 97 and member 79. In an alternative arrangement (Fig. 9), the contact member 41 has a notch 155 which pivots on a bearing 151 which fits in slots 159 in the dolly 47 and the fixed contact carrier 31 is located by a resilient clip portion engaging in a corresponding recess in the housing (not shown).