Performance and Efficiency of Redesign Induction Motor Using Asymmetric Windings

This paper investigates the performance and efficiency of redesigning squirrel-cage induction motors using fractional-slot asymmetric windings, particularly when the number of slots per pole per phase results in a fraction whose denominator is a multiple of the number of phases. Under such circumstances, conventional methods for calculating winding factors become ineffective due to the high degree of asymmetry and complex harmonic distribution. To address this challenge, three different winding configurations were proposed and systematically analyzed in terms of harmonic content, winding factors, and magneto motive force symmetry. Electromagnetic simulations were performed using the FLINT software to evaluate and compare their operational performance under rated conditions. The results demonstrated that a partially symmetrized asymmetric winding (Option III) could achieve acceptable thermal, magnetic, and electromagnetic performance, with a predicted decrease in rated power of approximately 12.5% compared to the standard symmetric winding. These findings support the feasibility and potential advantages of using asymmetric windings in motor repair, redesign, and performance optimization for machines up to around 3.5 kW.