GB420294A - Improvements in and relating to electric motor control systems - Google Patents

Abstract

420,294. Field control of D.C. motors. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.- (Assignees of Allgemeine Elektricitats-Ges. ; 2, Friedrich Karl-Ufer, Berlin) April 27, 1933, Nos. 12342 and 12343. Convention dates, April 27, 1932 and Sept. 21, 1932. [Class 38 (iii)] The series field current of a vehicle motor is diverted by the armature of a motor 8 which is connected across the field at certain controller steps, and at the time of its connection has a counter-electromotive force such that its resistance as a shunt is small, and which thereafter changes to increase its effective resistance. Motors 1, 2 are arranged for series-parallel and rheostatic braking control, and the diverter motor 8 is connected at the second controller step, and is effective only on the field 4 during the series stages. In the final speed stage a brake 11 may be applied to the motor 8 to give the top speed. This braking of the motor 8 may be under the control of a time relay energized on the last parallel step, and may be effective also when the controller is being moved to its " off " position. The motor 8 may be series, compound or separately excited, and may drive a flywheel or a fan. It is effective for all rheostatic braking stages. In a modification, Fig. 3, not shown, two diverter motors are employed alternately connected to the field and for short-circuit braking on successive controller steps. A further modification employs a single diverter motor which is reversed for each controller step. Alternatively, the field of the diverter motor may be disconnected during movement from one controller step, and reconnected when the next is reached. Specification 349,777 is referred to. The Specification as open to inspection under Sect. 91 comprises also arrangements in which relays controlled by the controller, and the diverted current, control short-circuit braking of the diverter motor between controller steps. This subject-matter does not appear in the Specification as accepted.