GB1051467A - - Google Patents

Abstract

1,051,467. Dynamo-electric machines. WINSTON RESEARCH CORPORATION. May 18, 1965 [June 1, 1964], No. 20962/65. Heading H2A. [Also in Divisions B3 and H1] A core-less rotor for a motor or generator comprises at least two arrays of conductors forming concentric cylinders, appropriate conductors in each cylinder being electrically connected at the ends of the cylinder, insulating material being interposed between the cylinders to provide a rigid structure. Fig. 1 shows a motor driving a capstan 16 for tape recording apparatus and comprising a four-pole permanent- or electro-magnet stator 32 and a rotor 24A, 24B attached to the lower end of the capstan 16 which is journalled about a stationary shaft 10. The rotor conductors are formed by stamping or etching transverse slots in two sheets of aluminium foil to form the spaces between conductors, the first foil then being wrapped around a steel mandrel, covered with fibre glass insulation and then by the second foil. Appropriate conductors of the concentric cylinders thus formed are electrically connected by welding, brazing, riveting or crimping after which the ends of the cylinders are cut off and the mandrel removed. The assembly is then vacuum encapsulated in epoxy resin after which the conductors at one end of the cylinder are cleaned in a lathe and plated with 10-12 mils. copper to form a commutator 25.