An analytical model for thermal and mechanical analysis of solid rotor induction motors

A two-dimensional simplified model of a solid rotor induction motors has been proposed for the analysis of the coupled electrical-thermal–mechanical behaviour of the rotor at steady state. Rotor is assumed to be an infinite cylinder, and the stator is assumed to have infinite magnetic permeability. The electrical model of the motor depends on the definition of the slip to which all the results are referred. This makes all the field variables functions of the radial coordinate only. Eddy currents, temperature field, and elastic displacement field within the rotor are solved analytically. Eddy current computations were compared with finite element solutions. Temperature and displacement fields as a function of slip have been presented. The proposed model has the distinction of being largely analytical, and it gives good estimates for the temperatures, and stress and displacement distributions within the rotor, therefore making critical predictions concerning mechanical integrity of the design, such as verifying that the rotor will not rub on the stator due to displacements as a result of both thermal and mechanical stresses.