A new type of insulation structure for class H motor

Abstract

We propose a design scheme for a new type of insulation structure for a class H shielded motor based on a study of the insulation systems of class H asynchronous motors and DC machines. We describe the choice of main insulation materials, such as Kapton polyimide film, flat copper wires wrapped by common Kapton film-46 composite, and a newly developed corona-resistant (CR) Kapton polyimide film-46, polyimide film glass cloth-reinforced mica paper tape and impregnating varnish, as well as their properties and technical indexes. By estimating the data of the thermally accelerated aging for this new type of insulating structure, we obtain a temperature index (TI) of 187/spl deg/C, and a thermal lifetime of 27 years by extrapolating to 150/spl deg/C. Thus, this new insulation structure not only provides a design basis for class H asynchronous machines, shielded machines and DC motors, but also improves their temperature rise and is a thin, low-cost insulation.