GB914601A - Improvements relating to high-speed circuit-breakers - Google Patents

Abstract

914,601. Automatic circuit-breakers. BARDEN, A. E. (I-T-ECircuit Breaker Co.). March 12, 1959, No. 8663/59. Class 38. (5). A high-speed D.C. circuit-breaker has a movable contact 70 held in its closed position, Fig. 10, by a releasable magnetic latch or coupling against the action of an opening spring 138, the latch or coupling comprising a pair of co-operating movable magnetic members 72, 92, one connected to the circuit-breaker operating mechanism and the other to the movable contact. The members 72, 92 are normally maintained in engagement with each other by the flux set up by a magnetizing coil 84. The movable contact 70 is moved from its open position, Fig. 12, to its closed position, Fig. 10, by a solenoid (not shown) moving a toggle 142, 148 into its over-centre position where it abuts a fixed stop 168, the member 72 and a lever 106 carrying the member 92 turning about a fixed pivot 98 to close the contacts. A fixed magnetic shunt 212 which links with the main current path through the contacts 70, 132 has an air gap in which the magnetic member 72 is located. In the event of a reverse current, the flux produced in the magnetic shunt 212 counteracts that due to the coil 84 and the spring 138 is able to separate the members 72, 92 and open the contacts, Fig. 11. A spring 160 is now able to collapse the toggle under the control of a dashpot (not shown) associated with the closing solenoid to reset the members 72, 92, Fig. 12. When the contacts are opened by the spring 138, rebound is prevented by a pivoted latch (not shown) carried by the member 72. The Complete Specification describes and illustrates in detail a constructional arrangement of the circuit-breaker.