Thermal analysis of induction and synchronous reluctance motors

In this paper the thermal behavior of two induction motors (2.2 and 4 kW, 4 pole) and two synchronous reluctance motors (transverse laminated) are investigated and compared. Both motor types use the same stator, but have different rotors. Using a lumped parameter simulation program, a thermal analysis has been also carried out and the obtained results have been compared to the experimental ones. A direct comparison of the thermal behavior of the two motor types has been thus made, for constant load and constant average copper temperature conditions. Since the synchronous reluctance motor has negligible rotor losses compared to the induction motor, it is capable of a larger rated torque, from 10% to more than 20%, depending on the relative size of end connections and motor length