US Patent 7977905 Electric drive

An electric drive which has an inductor with poles, an armature having a plurality of windings and rotatable relative to the inductor and its poles, and a control unit which, when a respective one of the windings of the armature approaches a respective one of the poles of the inductor, turns off a voltage supply to the winding so that when the winding passes the pole it does not have a voltage, and when the winding moves away from the pole the control unit supplies opposite voltage to the winding, and therefore no counter electric motive force is generated during the operation of the electric drive.