Measurement of the thermal characteristics of a stator-housing interface

Proper estimation of the thermal contact conductance at the stator-housing interface of electrical machines is necessary for the accurate prediction of thermal performance, since this material interface typically lies in the main heat extraction path. However, thermal contact conductance is a complex phenomena influenced by many factors including material properties, interface pressure and surface finish, making reliable analytical estimates challenging. In this paper, a simple heat-flow meter is used to experimentally measure the thermal contact conductance between representative stator and housing material samples under in-service conditions. This approach allows the various combinations of materials, cutting methods and surface finishes encountered in electrical machine manufacturing to be measured and assessed and could enable the expected thermal performance deviation between prototype and production manufactured electrical machines to be quantified.