Tangential forces in overlapped pole geometries incorporating ideally saturable material

The tangential force in overlapped-pole and attracted-slab geometries typical of electromechanical devices is examined for the case of magnetic or dielectric material having an ideally square saturation characteristic. Simple force expressions for large overlap are presented, these indicating in general a doubling of force as compared with the linear case, and a linear rather than square-law variation of force with driving potential difference (magnetic or electric). The approach for the overlapped-pole geometry, based on the physically nonrealizable idealization of ideally square material characteristic, yields results correlating remarkably well with experimental measurements.