GB369740A - Improvements in or relating to electric circuit breakers or like circuit rupturing apparatus - Google Patents

Abstract

369,740. Automatic circuit-breakers. RECORD, J. W. and RECORD ELECTRICAL CO., Ltd., Broadheath, Altrincham, Cheshire. March 17, 1931, No. 8179. [Class 38 (v).] Magnetic blow-outs. -The movable contact 23 is held in engagement with the fixed contact 7 by means of a toggle 35, 37, which is connected at one end 31 to the operating handle 29 and at the other end 27 to a spring-member 21 secured to a terminal 19. The above parts are located between side-cheeks 13 of an H-shaped magnet structure, the cross limb 17 of which carries a series coil 15 that produces a blow-out field between the upper ends of the cheeks 13 and a tripping field in parallel to the blow-out field between the lower ends, the latter field acting on an armature 41 to move a member 45 thereon to engage a part 39 of the link 37 and break the retaining toggle. The coil 15 is connected between terminal 19 and a terminal 3 and between the latter and one main terminal is a V-shaped series bimetal strip 51 the free end of which carries an eccentrically-pivoted, adjustable cam disc 55 engaging the free end of the armature 41. If the current increases dangerously, the strip 51 moves the armature nearer the magnet and at the limit the armature is attracted. The core may consist, Fig. 4 (not shown), of two U-shaped plates placed back to back to form an H, and in this form the armature may have a biasing spring and the strip may act directly on the armature and itself engage an adjustable stop. Alternatively, Fig. 6 (not shown), the side cheeks of the core may have flanges bent at right-angles to them and secured together to form the cross limb of the H. The bimetal strip may, alternatively, be energized from an independent source controlled by a press-button.