Design optimization and thermal analysis by FEM of an induction motor having high air gap

The authors have presented a method for the design optimization of a three-phase double squirrel-cage pump induction motor based on ten independent variables. The objective function to be minimized is represented by the motor capitalized cost per annum. The problem of the constrained optimization has been solved by resorting to the Lagrangian function method. This procedure allows us to reduce the annual cost by about 10%. Moreover, the thermal analysis carried out by means of the finite element method has led to a more accurate estimation of the temperatures in the various points of the stator, which is the most stressed part of the induction motor having high air gap.