Patent ID: 8701615

Claim:
An apparatus that improves rotation of a rotatable shaft about an axis, the rotatable shaft having a cyclical cogging torque acting thereon in a first direction, the apparatus comprising: a first support member that is coupled to the rotatable shaft for rotation therewith; a second support member that is adjacent the first support member, the first support member operable to rotate relative to the second support member; a plurality of first magnetic members coupled to one of the first and second support members, the plurality of first magnetic members including at least one inner magnetic member disposed at a first radial distance from the axis and at least one outer magnetic member disposed at a second radial distance from the axis; and a second magnetic member coupled to the other of the first and second support members, the second magnetic member disposed at a third radial distance from the axis, the third radial distance being greater than the first radial distance and less than the second radial distance, the second magnetic member operable to magnetically interact with the at least one inner magnetic member and the at least one outer magnetic member to provide an anti-cogging torque to the rotatable shaft in a second direction that opposes the first direction to at least partially offset the cogging torque.