GB658633A - Improvements in or relating to electric circuit breakers having arcing contacts - Google Patents

Abstract

658,633. Arc-rupturing in switches; contact-members for switches; switches, partly electromagnetic. WHIPP & BOURNE, Ltd., and WHIPP, I. T. L. Jan. 4, 1949, No. 161. [Class 38(v)] The movable main and arcing contacts 17, 18 of a circuit-breaker are carried by a member 19 pivoted between the contacts at 20 to an operating lever 21, and the " fixed " arcing contact 4 is urged about a pivot 6 by a spring 13, the connections to the external circuit being through conductors 8, 24, whereby when the breaker is closed electromagnetic forces tend to press the contact 4 more heavily on the contact 18, which pressure is transmitted by the member 19 to main contacts 1, 17. Pivotal movement of the contact carrier 19 is limited by a slot 23 therein co-operating with a pin 22 connected between the bifurcated end of the lever 21. To close the breaker a cam 34 is rotated clockwise about its pivot 35 causing a shaft 29, to which the lever 21 is secured, to rotate counterclockwise and the arcing contacts 4, 18, to engage. On further movement the pin 22 engaging the right hand end of the slot 23 compresses the spring 13 and the main contacts 1, 17 meet. In the closed position shown the pin 22 occupies the centre of the slot 23 and permits rocking of the carrier 19 about the pin 20 under the electromagnetic forces. On opening the breaker by tripping or by hand, the cam 34 is rotated counterclockwise and the spring 13 moves the pin 22 to the right hand end of the slot 23 and the main contacts 1, 17 separate. The spring 13 then continues to move the lever 21 and when the arcing contact 4 is arrested by a stop 16, the circuit is finally broken. The opening movement may be assisted by a weak spring 37. The member 19 also carries an arc horn 38, and an arc shoot and blowout coil may be provided. Further there may be several sets of main and arcing contacts and the lever 21 may move rectilinearly.