Characteristics Analysis of Induction Motor with an Unequal Slot Pitch Cage Rotor

Abstract

Recent developments in induction motors have been moving forward reducing the size and weight of motors. Furthermore for these motors, it demands for much quieter operating conditions to meet environment. Various design methods have been applied to reduce the vibration and acoustic noise of induction motors. One method is to make the slot pitches of the cage rotor unequal, to avoid the resonance with the natural frequencies of the stator frame. In this paper, our purpose is to create guidelines for reducing noise. As the first step for this purpose, we developed a method to analyze the voltage and torque equations of an induction motor with an unequal slot pitched cage rotor and discussed the characteristics from the analyzed currents.