Abstract: A novel stator assembly, D.C. electric motor, and method of controlling the speed of the motor is described. The stator assembly includes a pair of field poles, each having a field coil wound around a shank portion, a plurality of separately excitable field control coils wound individually around separate field pole leg members, and a face portion forming a bore for receiving the motor armature. The field poles also have a core portion which provides a magnetic path between the shank and face portion. This core portion permits the magnetic flux in the field poles to shift across the face portion when one or more of the field control coils are energized magnetically subtractive to the flux generated by the field coils. The speed of the motor may be controlled by energizing the field control coils and controlling their polarity with respect to the field coils. A motor controller for the motor according to the present invention is also described, and is particularly useful in an electric vehicle application.

Abstract: A novel stator assembly, D.C. electric motor, and method of controlling the speed of the motor is described. The stator assembly includes a pair of field poles, each having a field coil wound around a shank portion, and a plurality of separately excitable field control coils wound individually around the field pole legs defining a face portion of the field poles. The field poles also have a core portion which provides a magnetic path between the shank and face portion. This core portion permits the magnetic flux in the field poles to shift across the face portion when one or more of the field control coils are energized magnetically subtractive to the flux generated by the field coils. The speed of the motor may be controlled by energizing the field control coils and controlling their polarity with respect to the field coils. A motor controller for the motor according to the present invention is also described, and is particularly useful in an electric vehicle application.