A direct current motor has a rotatable axially slotted cylindrical armature and an even number of permanent magnet poles. The poles are spaced apart 360*/N where N is the number of poles. The poles can be asymmetrically shaped so that the points of maximum field strength of each pole are spaced 360*/N + OR phi from each adjacent pole to effect cooperative cancellation of cogging torque tending to be generated between the armature and the respective adjacent poles.