Separate multiple flux paths for an electrical generator or motor are provided in a single rotor machine by axially mounting a plurality of pole pieces on the rotor shaft. Each pole piece includes a central disc portion having a plurality of radial pole-forming projections, with the projections of adjacent...http://www.google.fr/patents/US5130595?utm_source=gb-gplus-shareBrevet US5130595 - Multiple magnetic paths machine
