Thermal Modelling of Induction Motors Based on Accurate Loss Density Distribution

Abstract

The ability to predict the temperature rise of a machine prior to its construction is as important as the ability to predict its performance. For a complex heat flow systems, such as electrical machines, the lumped parameter network technique still plays a very important role for the solution of heat flow problems. This paper discusses the development of the thermal model, taking into account the different material types and complicated geometries within the machine, as well as the different modes of heat transfer. However, to predict an accurate temperature distribution requires the knowledge of loss distribution in the machine. Using the temperature-time method a more accurate loss distribution is obtained. The model performance is validated against measured results obtained for a 4 kW, 3-phase, 4-pole, 415 V totally enclosed fan cooled induction motor.