GB648837A - Improvements in switching mechanisms particularly for controlling electric motors - Google Patents

Abstract

648,837. Electromagnetic switches; control of D.C. motors. IGRANIC ELECTRIC CO., Ltd. July 15, 1947, No. 18813. Convention date, Dec. 18, 1843. [Classes 38(iii) and 38(v)] In a controller for a split field series motor electromagnetically - operable direction controlling switches 1, 2 are combined with a selector switch 3, in such a manner that the switch 3 is operated one way by operation of switch 1 and the other way by operation of switch 2, release of switch 1 or 2 having no effect on switch 3 and the position of switch 3 being in this. way the correct one for effecting dynamic braking connections. The circuit arrangements are shown in Fig. 4, operation of the switch 1 for example by the press button 60 connecting the field winding f of the motor M in circuit between lines L' and L<SP>2</SP> and moving the switch 3 into the position shown if it is not already there, and release of the switch 1 completing a braking circuit 1c, 2c, 3, f. The switch 1 comprises a coil 1b and a plunger 12 connected resiliently to an extension 15 carrying contact bars 16, 17 co-operating respectively with fixed contacts 18, 19 and 20, 21. The switch 2 is similar. Each switch 1. 2 also has a collar 56 between which and a spring 57 lie the arms of a U-shaped lever 50 or 51 pivoted at its outer end, operation of either switch thus moving its lever 50 or 51 to tilt a lever 46 into the full or dotted position if it is not already there. The lever 46 is fixed to a rotatable sleeve carrying the contact arm of the selector switch.