A Feasibility Study of Additively Manufactured Heat Guides for Enhanced Heat Transfer in Electrical Machines

This article investigates a new heat extraction approach for application to high-specific-output electrical machines. The proposed technique employs thermally conductive heat guides (HGs) to provide supplementary heat evacuation paths for the machine regions, which are particularly susceptible to high power loss. Here, the research focus has been placed on the stator-winding assembly. The HGs investigated in this article rely solely on conductive heat transfer, in contrast to the solutions involving working fluid phase change, e.g., heat pipes. It is intended for the HGs to be an integral part of the stator-winding assembly, for e.g., HGs incorporated in the winding active and/or end region. Such arrangement, however, imposes several design challenges. These are related to the HGs being a source of additional power loss due to the machine's magnetic flux leakage. The objective of this study is to evaluate a concept of HGs, which are immune to the external magnetic field with good heat transfer capability. To facilitate that, a combination of detailed multiphysic design optimization and modern additive manufacturing (i.e., selective laser melting method) has been employed here. The theoretical analysis has been supplemented with an experimental work. A number of stator-winding hardware exemplars (motorettes) incorporating alternative HG designs have been fabricated and tested. This article provides a new set of experimental data in support of the authors' initial work on HGs' thermal behavior. The new research findings show that the optimized HGs allow for up to 85% improvement in dissipative heat transfer from the winding body and insignificant additional power loss, for the analyzed stator-winding assembly.