GB572871A - Improvements in and relating to electric switches, particularly alternating current contactors - Google Patents

Abstract

572,871. Actuation of switches. BRITISH THOMSON-HOUSTON CO., Ltd. (General Electric Co.). Aug. 20, 1943, No. 13643. [Class 38 (v)] In a contactor switch for A.C. the moving contact member 10 is closed by the energization of an electric motor 16, a spring 23 being wound up in the process ; on de-energization of the motor the spring unwinds driving the motor backwards and the contacts are opened at a slow speed so that the current is broken at the zero of the cycle without the production of a big arc. In the form shown in Fig. 1, the motor operates a wheel 14 through a friction clutch 25 and gearing 19, 21, and a crank pin 13 on the wheel 14 causes the longitudinal movement (with a little tilting) of members 12, 11, 10. The pin 13 moves through 180 degrees from one dead-centre position to the other being brought to a stop by the engagement of member 12 with a stop 57 on the wheel 14. The tilting of member 10 causes the breaking of the contacts 34 before the contacts 33 and the disposition of the contacts is such that each contact 34 is vertically above each contact 33. The movement of the wheel 14 also opens contacts 56, 56a removing the short circuit from a condenser 55 in the motor circuit and so reducing the voltage at the motor terminals at the end of the switching movement. The switch is also adapted for hand operation by a knob 37 which is first rotated, then pushed in or pulled out and then further rotated, there being a modified bayonet-slot connection between the rod 12 and a sleeve 38 surrounding it and between lugs 42, 43 on the sleeve and a surrounding casing. The knob is attached to the sleeve 38.