The thermal properties of high-voltage insulants

Lack of agreement between published values of the thermal properties of high-voltage insulants necessitates the development of relatively simple methods for their measurement. Transient methods for the determination of the thermal diffusivity of solids and thermal conductivity of fluids are described, with examples of their use and an estimate of their accuracy. Allowance is made for anisotropy in the case of solids. Suitable methods for determination of specific heat are discussed, and the importance of the rate of change of density of liquids with temperature is stressed.