This paper deals with the three-dimensional modeling of massive conductors
carrying a total imposed current and involving multiply connected regions.
Both stationary motion and time harmonic eddy current problems are consider
ed. The aim of the modeling is to determine the current distribution and th
e eddy current's effects inside the conductor, as well as to calculate the
Lorentz force acting on a conducting region. The choice of a suitable formu
lation based on solving the current vector potential T and the magnetic sca
lar potential phi is argued, then various methods for the restoration of th
e Ampere law in the multiply connected regions are presented Two methods fo
r calculating an auxiliary vector potential T-0 are applied in order to cal
culate the force acting on the armature of a railgun and the repulsion betw
een the electrodes of a vacuum circuit breaker, then the results are compar
ed.