SIMPLE FORCE EXPRESSIONS FOR IDEALIZED SATURABLE POLES AND WEDGES

Force expressions are presented for simple idealized magnetic pole geo metries with a) infinitely permeable pole material, b) ''square B/H'' saturable pole material, and c) ''square M/H'' saturable material, the third being the most realistic. The simplicity of the force expressio ns with saturation is surprising, and important conclusions can be dra wn about the role of saturation, the effects of different iron saturat ion models, and details of the field. For example, for the fundamental ly important saturable overlapping rectangular pole configuration, wit h saturable poles modeled as highly nonlinear, ''square M/H'' iron, th e useful transverse force for positive overlaps is F = mu(o)M(s)F, twi ce a comparable value for infinitely permeable poles. This paper is an exploration of how far one can go, using a variety of analytical nonn umerical techniques, in determining fields and forces when saturation effects predominate. The results give useful insights not easily obtai ned from numerical solutions and provide exact results in certain case s.