GB542585A - Improvements relating to high speed circuit breaker reclosing mechanisms - Google Patents

Abstract

542,585. Automatic circuit breakers; actuation of switches. BRITISH THOMSON-HOUSTON CO., Ltd. July 18, 1940, No. 11849. Convention date, July 18, 1939. Addition to 526,422. [Class 38 (v)] A tripped circuit-breaker is automatically reclosed by energy stored in a spring 33, which energy is automatically released by ard during, the opening movement of the operating-rod 1 so that re-closure is effected before the opening movement is completed, the rod 1 being latched closed at L2 independently of a trippable thrust transmitting linkage T. The closing linkage comprises a releasable arm 30 on which bears a roller 12 on a floating lever 6 having a pivot 7 normally held by a toggle 23, 24 releasable by a detent 25 and coil 52, and a pivot 9 whereby it is connected by link 10 to a pivoted lever 43 which has a part 44 in the path of movement of a roller 1<SP>1</SP> on the rod 1. Arm 30 is normally retained by latches L3, L4, the former being trippable by coil 46 and the latter having an extension 47 which is deflected by roller 1<SP>1</SP> when the rod rises to open the contacts. The circuit of 46 includes contacts S1 which are closed by cam 36<SP>1</SP> only in the fully-charged position of the spring 33, at other times the contacts S2 being closed to maintain an alternative circuit to contacts ml which are closed by arm 30 when the spring-energy is released . When trip relay FR is energized, it closes contacts fr2 to energize the coil 46 and free latch L3, and closes contacts fr1 to energize, over closed contacts a, the coil 40 which releases armature 39 and allows it to rotate about its pivot 38 and impinge on latch L2 to rotate it about pivot 38 and free rod 1. In rising, the latter operates latch L4, so allowing the spring 33 at once to expand and reclose the breaker, at the same time energizing at m1 the motor M which rotates cam. 36 clockwise. The roller 35 and seat 34 drop to the low part of the cam, arm 30 falls, and latches L3, L4 again reset, the continued rotation of 36 causing the seat 34 to slide on the stem 33<SP>1</SP> on seat 32 and stress the spring 33, whereupon the motor is disconnected at contacts 52. During the reclosing movement, the lever 43 acting through spring 49, restores the armature 39 against the trip magnet. The breaker can be closed manually from the fully-open position by tripping L3 by closure of switch C, during which operation, a cam 50 on rod 1 momentarily closes a switch b which operates a relay TR, the contacts tr1 of which remain closed while a time-lag expires, and prepare a free-release circuit for coil 52, which circuit can be completed by the relay FR. Manual tripping is effected by contacts O in shunt to those fr1, ready for re-closure by C.