GB406760A - Improvements relating to the control of electric motors for lifts or elevators - Google Patents

Abstract

406,760. Control of motors. WOOD, W., and WADSWORTH & SONS, Ltd., W., High Street, Bolton. Sept. 14, 1932, No. 25596. [Class 38 (iii).] Travelling to predetermined limits.-The brush rockers a, b, of a lift or elevator motor c, are connected by a chain or rope d passing over a pulley or like balancing member e, and round a drum f driven by an auxiliary motor h through a friction clutch ; so that rotation of the motor h causes the brush rockers to move equal amounts in opposite directions. Reversing contactors x, x', for the main motor are under the control of a car switch u, limit switches v, and a switch n which ensures that the brush rockers are in their slow speed position before the main motor is started. The auxiliary motor h is under the control of a contactor k and limit switches p, q. The contactor k closes forward contacts, corresponding to acceleration of the main motor, when its coil is energized by operation of the car switch u, and reverse contacts under the action of gravity when the coil is de-energized. Switches r, interlocked with car switches s, are provided whereby, if the brush rockers are not returned to the slow speed position when the car approaches a floor level, the supply to the main motor is cut off at such points that the car is levelled properly. The drum f may vary the speed of the brush rockers with constant auxiliary motor speed.