GB308794A - Improvements in induction electric motors - Google Patents

Abstract

308,794. Surjaninoff, M. March 28, 1928, [Convention date]. Alternating-current induction machines.-The stray fluxes which circulate in the stator core of an induction motor are reduced by increasing the reluctance of the path for the stray fluxes or by the provision of auxiliary fields. In the case of a bi-polar polyphase motor, Fig. 4, the working flux #8 passes through the air gap and rotor 3 whereas the leakage flux # circulates in the stator core 1 only. To reduce the leakage flux, slots 4, Fig. 5, may be formed in the outer periphery of the stator core. Alternatively, the slots may be cut through to the air gap. In a modification, Fig. 7, one or more single phase auxiliary coils 6 are arranged in the stator in such a way that the leakage flux is diverted into the air gap. The coils are preferably displaced 90 electrical degrees with respect to the main winding conductors which carry current of the same phase. According to the Specification as open to inspection under Sect. 91 (3) (a) the slots 4 may be inclined to the rotor axes to the extent of one pole division. In the form shown in Fig. 9 (Cancelled), auxiliary windings 11, 12 carrying continuous current are arranged on the rotor to divert the leakage flux into the rotor. This subject-matter does not appear in the Specification as accepted.