Thermal Property Determination of Different Electric Machine Wire Types by Model Variable Fitting on Measurements

This paper proposes a combined experimental and model based approach to compare and determine the thermal properties of different wire types of electric machines. With the increasing trend in power density, reliable thermal models are key in the design of electric machines which rely on the accuracy of the input parameters. These thermal properties highly depend on the manufacturing processes and knowledge on material properties which highly vary within scientific literature. Based on the experiments on different windings assembled on identical motorettes, thermal properties are fitted with a lumped parameter model and uncertainties are quantified. These are used in a model based thermal comparison of the wire types. The rectangular copper wire is performing best, followed by the rectangular aluminum, thin stranded, thick stranded and finally Litz wire. The results show the reliability of the approach in the design of electric machines.