A Comparison of the Electrical Endurance of Plasma Sprayed Aluminum Oxide to Existing Insulation Materials

As electric machine power levels rise, so does the need for improved thermal management techniques to manage the increased heat production. The polymers used in most of the insulation in low to medium voltage machines have excellent insulative properties, but their low thermal conductivity traps heat in the stator slot and accelerates the degradation of the insulation. New insulation strategies need to be developed that are capable of withstanding higher temperatures and conducting heat away from the conductors in a more efficient manner. Plasma sprayed ceramics have the potential to meet these requirements but are untested as long-term electrical insulators. This paper presents the results of a study designed to test the electrical characteristics of plasma sprayed aluminum oxide over time, and compares the behavior to well established machine insulation materials that underwent identical accelerated aging cycles.