A surface integral approach to determine the effects of iron on axisymmetric coil systems

Abstract
The scalar potential of any system of axisymmetric conductors can be expanded in terms of Legendre polynomials. This paper describes a method for including the effects of a spherical iron shell into the Legendre polynomial expansion. The scalar potential is found using a surface integral approach by dividing the iron surface into elements over which the potential is constant and then using point collocation. Numerical results are obtained for a range of values of permeability by varying the number of elements and are found to agree well with the analytical results.