Estimation of equivalent thermal parameters of electrical windings

The equivalent bulk thermal properties of electrical winding samples are measured experimentally. An analytical relation and a finite element thermal model of the conductor and insulation amalgam are compared with the test results. The thermal parameters are verified by the construction and dc test of three air-cored inductors with differing material configurations. The finite element implementation allows the effects of conductor placement, dimensions, and insulation system to be studied and facilitates an initial estimate of the thermal properties of a winding employed in an electrical machine design.