Analysis of rotor bar number on induction motor performance characteristics and rotor temperature

This paper investigates the influence of rotor bar number on the thermal and electromagnetic performance of induction motors using a combined FEM--thermal modeling framework. A systematic analysis covering 8--26 rotor bars was conducted under both constant voltage and constant current conditions. Results show that rotor temperature and torque ripple are strongly dependent on bar count. A multi-objective optimization function is proposed to determine the optimal bar number by balancing efficiency and temperature rise. The novelty of this work lies in integrating thermal constraints into rotor bar selection, providing practical guidance for designers. Validation was performed using Motor-CAD and an extended lumped parameter model, demonstrating good agreement.