Stator Winding and Insulation
Stator windings are constructed from copper rectangular wires. The wires are preinsulated with enamel varnish in combination with glass silk and varnish. The winding is of double layer type, made of individually shaped and continuously insulated coils. The basic materials are mica and epoxy resins.
Prepared coils are continuously taped along the whole length with porous tapes on the basis of glass and mica paper. Such insulated and tested coils are inserted in the stator core, and then all the required connections and tests are carried out prior to vacuum pressure impregnation. The process of vacuum pressure impregnation is followed by the stiffening process in furnace, tests and the insertion of the stator core with winding into the frame.
Then the final tests are performed. The insulation system is of class. It is moisture proof and it practically has no limitation with regard to climate conditions, salty atmosphere, acids and lies. By the mentioned insulation system, great mechanical strength of the winding ends has been obtained. There is no limitation to reversals at residual fields of any magnitude and phase angle.