Patent ID: 7898135
Filing Date: 2011-03-01
Classification: H02K

Abstract:
1. An electro-mechanical device comprising: a rotor having a plurality of poles arranged about a central axis of rotation; and a stator including a plurality of stator segments arranged on a circle that circumscribes the rotor and defining a magnetic flux path, said stator also including a plurality of permanent magnets, each of which has north and south pole faces oriented in a first direction and is positioned between a different pair of stator segments among the plurality of stator segments, wherein the different pair of stator segments each has permanent magnets with north and south pole faces oriented in a second direction opposite the first direction, wherein each stator segment has an associated coil, which when energized produces flux that opposes flux from the permanent magnets, such that the flux from the permanent magnet traverses into the rotor and which when de-energized isolates the flux from the permanent magnets to the stator with the rotor experiencing little or no cogging torque.