ON THE ROLE OF SYMMETRY AND ANTISYMMETRY IN BIE FORMULATIONS OF EDDY-CURRENT PROBLEMS OF MULTICONDUCTOR SYSTEMS

The eddy current problems of multiconductor systems are considered for those cases in which we are interested to know the magnetic field dis tribution over selected conductors only. For these problems the classi cal approach to reduce the number of unknowns in the formulation of th e numerical procedure is to replace other current-carrying conductors by fictitious current filaments carrying the same total currents, In t he present paper the error due to this approximation is estimated in r elation to the kind of symmetry of the problem, It will be shown that the factor governing the approximation error is the number of ANTIsymm etric lines, namely, the error is smaller the greater the number of an tisymmetric lines in the problem, In problems,vith double antisymmetry the error is reduced by two orders of magnitude as compared with the formulations of the problems without symmetry, Some examples are inclu ded to illustrate the theory.