Temperature Distribution in Materials with Positive Temperature Coefficients of Electrical Conductivity When Heated by Eddy Currents

Steady-state digital and analytical solutions are given for the temperature distribution in slabs and cylinders of materials heated by varying magnetic fields. The materials are assumed to have a positive temperature coefficient of electrical conductivity of the type associated with semiconductors. The stability of the temperature distribution is investigated. It is shown that the solutions can be either stable or unstable, depending upon the size of the sample. Some of the practical significance of such heating is discussEd in relation to the design of high-power wideband transformers.