Analysis of magnetic rollers with the finite element method

Multipole configurations are used as magnetic rollers in eddy current separators as well as in copy machines. The magnetic field attracts ferromagnetic particles. Therefore, it is the aim to calculate the magnetic field distribution and the force density distribution, even if only the magnetic field outside the magnetic roller is available. Transforming the measured magnetic field values into a set of magnetic vector potentials and using them as the magnetic source in the finite element analysis, makes this method independent of the real excitation (permanent magnets or electromagnets). In this way is possible to evaluate the force components acting on the particles.