Patent ID: 8378542

Claim:
A magnetic center-finding device comprising: a magnet-free rotor movable around a rotation axis, comprising a first mechanical support structure, a first rotor-mounted magnetic yoke secured to the first mechanical support structure at a first distance from the rotation axis, and a second rotor-mounted magnetic yoke secured to the first mechanical support structure at a second distance from the rotation axis, wherein the first distance is different from the second distance; a stator, comprising a second mechanical support structure, an upper stator-mounted magnetic yoke secured to the second mechanical support structure and a lower stator-mounted magnetic yoke secured to the second mechanical support structure, the upper stator-mounted magnetic yoke and the lower stator-mounted magnetic yoke positioned between the first rotor-mounted magnetic yoke and the second rotor-mounted magnetic yoke, wherein at least two air gaps are formed and positioned at a location adjacent to each of the first distance and the second distance that separate the first and second rotor-mounted magnetic yokes from the upper and lower stator-mounted magnetic yokes; a plurality of windings disposed adjacent to the upper and lower stator-mounted magnetic yokes, each of the windings having a winding current, to provide power; and a plurality of magnets disposed adjacent to the plurality of windings; wherein: said plurality of windings comprises a first set of windings powered by a winding current and wound around said lower stator-mounted magnetic yoke and a second set of windings powered by a winding current and wound around said upper stator-mounted magnetic yoke; said plurality of magnets generates a magnetic flux following a magnetic path which passes through both said upper and said lower stator-mounted magnetic yokes and through said airgaps; and said first set of windings and said second set of windings generate a magnetic flux that follows a magnetic path that also passes through both of said upper and said lower stator-mounted magnetic yokes and through said airgaps.