Two speed motor for automatic washing machine - has composite rotor comprising two concentric core rings with short circuited induction motor winding in outer ring

摘要

The two speed motor functions as an induction machine at low speed and as a commutator motor at high speed. The four pole induction motor rotor comprises a core ring (7) with a two phase short circuited bar winding (10). This fits over a core cylinder (8) carrying the windings (12) for the commutator motor rotor. Using separate cores gives greater freedom of slot number choise to suit the particular winding. The core material (13) under the outer winding (10) provides a path for the induction motor flux and thus greatly limits the parasitic retarding torques generated in the commutator winding.