A starter-generator system is configured to be operable at multiple
variable frequencies. The starter-generator includes a rotor and a
stator. The rotor is configured to rotate and has a single main field
winding wound thereon. The stator has at least a first stator winding set
and second stator winding set independently wound thereon. Upon
electrical excitation and rotation of the rotor the starter-generator
supplies electrical power from each of the stator winding sets at
different frequencies. Also, upon electrically exciting one or both of
the stator winding sets with appropriate AC power, the rotor will rotate
and generate a starting torque.