Survey of Insulation in Electrical Machines for Aerospace: Systems, Materials & Inspection

Electrical machines have made significant inroads in the transportation sector in applications such as electric vehicles, rail, and aerospace. Amongst the key critical technologies for electrical machines, robust electrical insulation is essential for reliable operation. Therefore, insulation systems have attracted considerable research attention in recent decades spanning design, material selection and testing methods for inspection. This paper provides an overview of the main insulation systems and materials used in electrical machines, with a focus on aerospace applications. It reviews the main stresses to which insulation components are exposed, the state-of-the-art in diagnostic tests, and inspection methods. The paper concludes by discussing the challenges of electrical insulation, with reference to the inspection and repair of electrical machines in aerospace.