A note on the surface loss in a laminated pole-face

Linear electromagnetic theory has been used to obtain a formula for the surface eddy-current loss in a laminated pole-face due to the flux ripples induced by the opposing slotted armature, without any restrictive assumption being made as to the thickness of the laminations. Earlier formulae have been examined in the light of this more general theory and a formula derived by the author´s father the late Dr. F. W. Carter, has been found to be a good approximation over a range of conditions frequently encountered in practice.