Numerical analysis on impact of choice of number of rotor slots on performance of three phase induction motor

Abstract

Abstract This paper gives an insight of the geometrical configuration of a three phase induction motor based on classical design approach and has focused on the design of stator and rotor slots. A thorough investigation on the performance analysis of a sample motor is carried out using its finite element model, by varying the number of rotor slots. It explores the power, torque, current, speed, efficiency and power factor. In addition, the losses and torque ripple are also studied using equivalent circuit analysis and motion analysis respectively. For the chosen three phase induction motor, the optimum design parameters which provide a compromise between torque ripple and good overall performances, are recognized to be that for rotor slots 19. The performance of the motor is analysed for three different rotor bar materials namely, copper, aluminium and titanium. The simulation results show that the use of copper and aluminium as rotor bar material gives good efficiencies of 90.3% and 90.2% respectively. The efficiency of the motor with titanium rotor bars is only 75.8%. It is observed that, three phase induction motor with titanium rotor bars exhibits linear torque speed characteristics and good thermal stability. These findings can be adapted for the design of three phase induction motor for industrial applications based on their needs.