GB673793A - Improvements in or relating to low inertia dynamo electric machines - Google Patents

Abstract

673,793. Armature windings for dynamoelectric machines. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Nov. 8, 1950 [Nov. 14, 1949], No. 27293/50. Class 35. An armature winding without a magnetic core is made by covering the outer surface of a mandrel with thermosetting plastic material, winding the rotor winding on the mandrel, baking the assembly to harden the plastic material and removing the mandrel. The mandrel 20, which is preferably slightly tapered for ease of removal, carries five rows of pins 21, 22, 23, 24 and 25, inserted into radial holes in the mandrel and about which the winding 11 is wound. Before the insertion of the pins, a steel ring 13 which houses the bearing 14 and may be knurled to improve the adhesion to the end windings, is placed over the end of the mandrel. The mandrel body is lubricated and covered, together with the ring 13 with a thin porous paper or tape 26 on which the thermosetting plastic 29 is spread. After binding with wire 28 and removing the pins, the mandrel and winding are baked to harden the varnish. The binding wire is then taken off and the mandrel withdrawn from the winding. If desired, a two-layer winding may be produced by leaving the pins in position during the first baking and applying a second winding. The shaft 9 is then screwed at its cup-shaped end portion 12 to the end of a further mandrel which fits within the cylindrical winding unit. The outer surface of the shaft end portion may be knurled and is bonded to the end of the winding by baking with a further thermosetting plastic, the winding being bound with wire or tape, if desired. On cooling, the mandrel is unscrewed and removed while a commutator 16 is pressed on to the shaft 9 and connected to the wires 27. In service, the working flux from the poles 4 passes through the armature windings to a fixed solid or laminated core 7.