Introductory overview

Abstract

EM field modelling is an old and well established science; or should that be art? Algebraic analysis using Schwarz-Christoffel transformations were used by J.J. Thomson in 1883. Then in 1900, F.W. Carter published a paper on airgap induction, using conformal mapping. Many other papers followed. For the most part, these were all concerned with field solutions in parts of devices, not the whole device. Somewhere around the mid-twenties, finite differences (FD) appeared applied to both electrical and magnetic field problems. The labour involved was considerable, and it was not until the introduction of digital computers in the early sixties that the technique became widely used. Within ten years FD gave way to finite element modelling. Possibly the first paper in which the technique was applied to electrical problems was by Silvester in 1969. Since that time, the method has become extremely popular for the solution for both magnetic and electric field problems. More recently, boundary element methods have appeared. These have their own loyal following. It has to be added, that much of the early development of all the above numerical methods owes much to structural engineering. That situation has now changed, and there is a healthy flow of new ideas in both directions.