Patent attributes
A rotor for an electric machine having posts extending partially or completely between end irons. Each end iron is formed of a single piece of magnetic material with the posts extending from it, including the other end iron where the posts extend completely between them. Magnets are arranged between the posts with poles facing the posts to concentrate flux. In order to prevent too much of the flux from being drawn into flux paths through the end irons, the total magnetic flux is made to exceed a saturation flux of at least a portion of the flux path. This may be achieved by using interdigitated posts extending only partially between the end irons to provide gaps in the flux path, by providing flux resistors in the end irons to reduce a saturation flux below the total flux, or by using high aspect ratio magnets or posts so that the magnetic flux exceeds a saturation flux of the posts or end irons.
