Skin–Effect in the Rotor of Induction Salient – Pole Electric Motor

Abstract

The same harmonic components of forward and backward rotating magnetic fields are created in the single – phase induction salient – pole motor. The magnitudes of higher order harmonics of these fields may be of the same order as a fundamental. These rotating fields of higher harmonics induce in the rotor electromotive forces the frequency of which increase while the rotor slip decrease. The frequency dependences upon slip of electromotive forces induced from 1, 3, 5–th forward and backward rotating magnetic fields harmonics in the rotor are presented. The values of the rotor resistance change coefficients from 1, 3, 5 forward and backward rotating field harmonics at slip range from 0 till 1 are calculated when the rotor slot depth values are the following: h = 1,2 ⋅10−2 m; h = 1,0 ⋅10−2 m; h = 0,8⋅10−2 m; h = 0,6 ⋅10−2 m. The graphs representing equipotential lines ( k const R = 1,03 = , k X = 0,97 = const ) at slip and rotor slot depth plane are given. The critical rotor slot depth is determined when the skin – effect may be evaluated for the induction salient – pole motors operating at low slip. Ill. 8, bibl. 6 (in Lithuanian; summaries in Lithuanian, English, Russian).