Finite-element method for calculating power frequency 3-dimensional electromagnetic field distributions

A finite-element method for calculating power frequency 3-dimensional electromagnetic field distributions is described. The problem region is partitioned into regions which contain no eddy currents, and regions in which eddy currents flow in such a way that the dividing surfaces are the surfaces of the conductors. Magnetic scalar potentials are then used to describe the field in non-eddy regions. A magnetic vector potential A is used in eddy regions. If the conductor permeability is nonuniform Lagrangian multipliers are also needed to enforce the zero divergence of A.