The book investigates the thermal behavior of a rotating electrical machine when subjected to a mechanical failure. Linear and nonlinear system identification techniques are used to evaluate the temperature rise of the motor. Two mathematical formulations: one linear (ARMA) and one nonlinear (NARMA) were respectively chosen for the purpose of analyzing the thermal dynamics of the system. The obtained models were validated according to the procedures: k-step forward prediction, residual analysis and the statistical indexes root mean square error ("RMSE") and mean absolute percent error ("MAPE").