The calculation of the magnetic field of rotating machines. Part 3: Eddy currents induced in a solid slab by a circular current loop

The paper contains a detailed analysis of the eddy currents induced in a semi-infinite slab by a circular current outside the slab. Particular attention is paid to the magnetic field outside the slab, and the conditions are explained under which the method of images can be safely applied. The effective impedance of the slab is calculated, and the results are compared with recent experimental work. The application of the work to the end-fields of rotating machines is discussed, and it is shown that the diameter of the end-windings and the degree of saturation of the end-plates have a profound effect on the eddy-current behaviour.