Modeling and analysis of cage induction motors under rotor misalignment and air gap eccentricity

Air gap asymmetry exists in all electric machines. This asymmetry creates unbalanced magnetic forces that act both on the rotor and the stator of the machine. Bearing damages and excessive vibration and acoustic noise could be traced to these forces. In this paper, modeling of squirrel cage induction motor under different air gap asymmetries is presented. Transient and steady state unbalanced magnetic forces at the two ends of the rotor are studied. Using the magnetic equivalent circuit method (MEC) for the modeling of induction motor, the most important factors affecting dynamic behavior of induction motors are also considered. Experimental results are provided to validate theoretical findings.