GB587663A - Improvements in or relating to dynamo electric machines - Google Patents

Abstract

587,663. Exciting dynamo electric machines. ENGLISH ELECTRIC CO., Ltd., and BINNEY, E. A. Jan. 12, 1945, Nos. 4304/46 (divided out of 579,570) and 23299/45. [Class 35] A D.C. motor has two armature windings with corresponding field windings wound for different pole numbers, one armature winding co-operating with a separately excited field winding and energizing a field winding linked with the other armature winding which is also subjected to a field produced independently of the exciting armature winding. The motor may give constant speed when operating on a varying voltage supply and be therefore suitable for driving a generator. In the form shown, the motor has armature windings connected to commutators 11, 13 in a stator with four main polar projections with separately excited winding 20 and shunt (or series) winding 19 producing a two-pole field linking the winding of comutator 11 while the armature winding of commutator 13 which excites winding 20 is linked by a four-pole field produced by separately excited opposing windings 21a and 21 the latter fed from sub-exciter 43 on the shaft of the motor and the A.C. generator 35. When a constant voltage source is available for field 21a, and generator field 36, winding 21 may be connected across the A.C. generator through a rectifier. In the case of other drives, field winding 21 may be controlled by a governor-operated rheostat and/or a non- linear resistor and the motor may also have a damping or compensating winding while the commutator 11 may also have a pair of short circuited brushes. Specification 560,531 is referred to.