Abstract: A fractional-power electric motor is provided to generate varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on a battery-powered source. The electric motor includes a rotor and a stator assembly. The stator assembly is disposed around the rotor and is inductively coupled to the rotor. The stator assembly further includes a plurality of poles, each having a main winding and at least one fractional-power winding. The main winding and associated at least one fractional-power winding on each of the stator poles are wound so that the magnetic fluxes generated therefrom are added. Power switching circuits are provided for independently energizing the main and fractional-power windings on each of the stator poles. A controller is used to control selectively the frequency and duty cycle energization of the power switching circuits to vary the rotational speed of the rotor and the amounts of torque supplied to the driven member.

Abstract: A fractional-power electric motor is provided to generate varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on a battery-powered source. The electric motor includes a rotor and a stator assembly. The stator assembly is disposed around the rotor and is inductively coupled to the rotor. The stator assembly further includes a plurality of poles, each having a main winding and at least one fractional-power winding. The main winding and associated at least one fractional-power winding on each of the stator poles are wound so that the magnetic fluxes generated therefrom are added. Power switching circuits are provided for independently energizing the main and fractional-power windings on each of the stator poles. A controller is used to control selectively the frequency and duty cycle energization of the power switching circuits to vary the rotational speed of the rotor and the amounts of torque supplied to the driven member.