Calculations for coreless induction furnaces

Calculations of electrical characteristics of coreless induction furnaces usually are made by means of the penetration formula (equation 18 in this paper); this formula, however, gives only an approximation which is fairly accurate only at relatively high frequencies. As a wide range of frequencies can be used in these furnaces, there is a need for calculations that are good at any frequency; to meet this need, the fundamental calculations upon which the penetration formula is based are presented in this paper.