Magneto-thermal coupled analysis of canned induction motor

The authors present the calculation of the distribution of the transient temperature in the rotor bars of a canned induction motor, during locked rotor conditions, where the phenomena of electromagnetically induced currents and heat transfer are coupled. They have developed a coupled finite element electromagnetic code called WEMAP in which the calculated power loss densities are used as the heat sources for a transient thermal solution in subregions of the original problem geometry. These subregions are enclosed by surfaces on which either temperature or a convection boundary condition is known. In addition, the change in rotor bar resistance as a function of the temperature is included in these calculations. The calculated temperatures are compared with test results, and favorable agreement is obtained