A polymer composite electrical machine
Rather than being encased in a housing, as is traditional, the Sustainable and Green Engine 2 (SAGE2) demonstrator will have two counter-rotating propellers that are open to the environment. With EU funding, the project COTEM (Advanced electrical machine manufacturing process implementation and tuning based on composite material process technologies) successfully developed an optimised manufacturing process to produce the electrical de-icing machine that supplies power to the de-icing system. The machine is a complex assembly of enamelled winding insulated from a magnetic core by layers of fibre glass-reinforced thermoset resin composite. The outermost layer is also a different high dielectric (highly insulating) thermoset resin. In particular, manufacturing the complex electric machine was no easy task given the disparate materials employed and the numerous material interfaces. In more detail, the assembly consists of an insulating polymer matrix with anodised aluminium sheets as reinforcements, making one type of interface. There are two more critical interfaces: the interface between the main insulation and the magnetic core, and that between the main insulation and the matrix. Important parameters for resin selection were thermal stability, viscosity, weak shrinkage (inversely thermal expansion) and material health. Researchers investigated two different resin impregnation processes and introduced the impregnating material using pressure. COTEM's new prototype machine is of major importance to small- and medium-sized enterprises that do not otherwise have the infrastructure to exploit their abilities in new markets.
Keywords
Electrical machine, open rotor, aircraft, propellers, de-icing, COTEM