GB450176A - Improvements in and relating to systems for controlling the rate of variation of the magnetism of an electromagnet or electric generator - Google Patents

Abstract

450,176. Exciting dynamo-electric machines ; electromagnets. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London. Jan. 17, 1935, No. 1624. Convention date, Jan. 17, 1934. Addition to 370,532. [Class 35] [See also Group XXXVII] In a system for controlling the variation of the magnetism of an electromagnet, or the field winding of a generator G, according to the parent Specification, an additional voltage source is connected in the circuit of the armature 2 of the auxiliary machine, and acts in such a sense as to accelerate the change in excitation. The additional voltage source may comprise a voltage dividing resistance 5, as shown, a battery, or a generator. A controller 9 controls the direction of excitation of the field winding, and the direction in which the additional voltage acts by means of interlocked reversing contactors 6, 7, and the field circuit is completed through a resistance 4 by a contactor 8 also under the control of the controller 9. With the field fully excited and the controller in position 2, the field may be reduced by returning the controller to position 1, and then back to the off position. A sudden reversal of the fully excited field is prevented by controlling the contactor 8 by a time relay, or in dependence on the excitation current. Alternatively, the excitation current may control an electromagnetic locking device on the controller.