GB731570A - Improvements in and relating to the control of electric motors - Google Patents

Abstract

731,570. Control of A.C. motors. GENERAL ELECTRIC CO. April 28, 1953 [May 7, 1952], No. 11716/53. Class 38 (3). A single-phase motor has a running winding 2 and a starting winding 3 which is connected in series with a capacitor 5, the motor being reversed by means of a switch 22. When the reversing switch is moved to engage contact 13, a circuit is completed through the coil of relay 9, a speed-responsive switch 17, and the starting winding. Relay 9 then closes contacts 37, 38, so that the running winding is energized through contacts 28, 29, and the motor starts and accelerates. Opening of the switch 17 disconnects the starting winding, but the energization of the relay 9 is continued by the current in the running winding. To reverse the motor, the switch 22 is moved to engage contactl4, whereupon the relay 9 is de-energized and the motor windings 2, 3 are connected in a loop circuit for braking. The braking circuit is opened by the switch 17 when the motor speed falls to a low value, the relay 10 and the starting winding being energized by the same movement of the speed-responsive switch. The running winding is then energized in the opposite sense and the motor accelerates in the reverse direction. Different arrangements of the contacts of the relays 9 and 10 are described, Figs. 2, 3 (not shown). Specification 697,597 is referred to.