GB434095A - Improvements in and relating to systems of electric motor control - Google Patents

Abstract

434,095. Master control of D.C. motors. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Starie, G. B.; 73, Van Antwerp Road, Schenectady, New York, U.S.A.) Nov. 20, 1933, No. 32344. Void [Abridged as open to inspection under Sect. 91 of the Acts, May 22, 1934]. [Class 38 (iii)] In a sequential contactor system, movement of a controller 29 energizes one of two reversing contactors 23, 26 to complete energizing circuits for accelerating contactors 18, 19, 20 which open to insert accelerating resistance 12, 13, 14, in the motor circuit and complete, at contacts 41, 42, 43, an energizing circuit for a selfmaintaining starting contactor 44. The motor circuit is thus completed, and the contactor 44 in closing short-circuits the coil of the contactor 18 which is operated by spring or gravity after a time interval to cut out the section of resistance 12. The coil of the next contactor 19 is thus short-circuited, and the operations are repeated to accelerate the motor in timed steps. In a modification, the system is under the control of push-button switches, and the reversing contactors act as starting switches. There is also provided a dynamic braking resistance connected across the motor armature by the operation of a relay, the coil of which is connected across the armature through normally closed contacts on the reversing contactors.