Thermal analysis in an induction machine using thermal network and finite element methods

Winding damage, except when caused by accidents, depends on the wear level of the windings themselves; the wear is a function of the time and of the temperature. This is why is is necessary, at the design stage, to foresee with a certain degree of accuracy the thermal stresses to which the electrical machine is subjected under rated operating conditions. The results obtained by the thermal network method (TNM) and by the finite element method, both used for the thermal field analysis of a three phase asynchronous motor with deep-bars and squirrel cage rotor, during steady-state operation, show that the calculated temperatures are within the limits required by standards. The use of FEM instead of TNM for calculating the temperature distribution is very important for the optimal design of the whole machine in general and of the rotor squirrel-cage in particular