GB318111A - Improvements in and relating to systems of electric motor control - Google Patents

Abstract

318,111. International General Electric Co., Inc., (Assignees of Allgemeine Elektricitõts-Ges.). Aug 27, 1928, [Convention date]. Master-control systems; controllers, actuating by electric motors. - In a train motor control system comprising a master controller and a pilot motor operating a drum controller through a flexible connection, the drum controller is caused to follow the movements of the master controller by a Wheatstone bridge connection through a relay arranged to start, stop, and reverse the pilot motor. In the arrangement shown in Fig. 1, a two-armature pilot motor 1, 2 is started and stopped by a polarized relay 9 connected across resistances 16, 17 having tapping-contacts co-operating with contacts on the drum controller and the master controller respectively. The arrangement includes a motor field resistance 14 for the purpose of moving the drum controller faster in the decelerating than in the accelerating direction, a constant current resistance 18 to equalize the action of the relay 9, and a drum-controller brake-coil 8 to prevent over-running. The arrangement may also include a relay 12 for suspending the follow-up movement if the motor current exceeds a permissible limit during acceleration. The relay acts by opening the. pilot-motor circuit, and a subsidiary arrangement is described whereby the opening can take place only during intervals between definite switching steps of the drum controller. An arrangement is described whereby the opening of a no-volt or overload circuitbreaker energizes the pilot-motor in the direction to bring back the controller to its " off " position.