Effect of Number of Stator Slots on the Starting Torque of a Line-Start Three-Phase Reluctance Motor with Double Rotor Cage Bars

This paper analyses the effect of number of stator slots on the starting torque of a three-phase Line-Start Synchronous Reluctance Motor (LS-SynRM) with double rotor cage bars. The analysis focuses on distributed three-phase windings housed in 24 stator-, 36 stator-and 48 stator-slot cores. The machines have been designed with the same dimensions and rotor specifications but with different number of turns per phase. A winding function approach is utilized to study the magnetomotive force (MMF) distribution of each stator winding configuration under full-load operation. The 2D Finite Element Analysis (FEA) under ac magnetic transient solution is used to simulate the flux-density and the torque characteristics, under full-load operation. The FEA results evidenced that all three LS-SynRMs stall for about ± 20 mSec at starting, before the acceleration begins. A prototype of the LS-SynRM with 36 slot is manufactured and tested. The results are within the simulated results.