GB507869A - Improvements in electric supply systems supplying current to d.c. motors - Google Patents

Abstract

507,869. Exciting dynamo - electric machines. ENGLISH ELECTRIC CO., Ltd., BASTON, C. E., and BINNEY, E. A. Sept. 17, 1937, No. 13045/38. Divided out of 485,312. [Class 35] [Also in Group XXXVII] A generator 6 has a field winding 6a fed from an exciter 5 which, by being provided with a field winding 5a in series with the generator armature and a biassing field winding 5b, energizes the generator field 6a in accordance with any deviation of the armature current from a predetermined value and in a sense to oppose such change, one or more additional field windings 6c being provided on the generator energized solely in direct dependence on and producing an excitation varying as a continuous function of the voltage of the generator or of the power supplied thereby, so that on any change of excitation produced by the exciter, the field or fields 6c continue the change until the generator current is restored to substantially the predetermined value. The field winding 6c may be connected across the generator armature. Where the generator is driven by a motor 1 connected to an external source, the field winding 6c may be connected as shown in series with the motor 1. The generator may supply a motor 7 and control it both for acceleration and regenerative braking. The operation of the equipment is substantially the same as described in Specification 485,312 except that the variation of energization of the generator in accordance with power is provided by the additional field 6c instead of by the changes in operating speed. The exciter 5 need not be coupled to the generator, An additional field winding on the exciter 5 may be provided connected in series with the motor 1 and a shunt field on the generator may be additional to the field 6c connected in series with the motor 1. The biassing of the exciter may be provided in part by a shunt field winding. When the motor is up to full voltage it may be transferred to an external source as described in Specification 485,312.