Leakage flux and surface polarity in iron ring stampings

The paper deals with the conduction of magnetic flux through iron circuits magnetized by windings which surround only a part of the iron. The complete solution is obtained for an infinitely long hollow iron cylinder magnetized by a single current loop, and it is shown that surface polarity on the iron plays a dominant part in causing the flux to be substantially constant at all sections around the circumference of the cylinder. Experimental evidence is brought forward in support of the theoretical investigation.