Low profile starter-generator

A power system for a vehicle may comprise an electric machine interposed between an engine and a transmission of the vehicle. The electric machine may comprise an exciter generator with exciter armature windings surrounding an axis, a main generator with main field windings surrounding the axis so that the exciter generator and the main generator are concentric and a rotor coaxial with the axis and the rotor supporting the exciter armature windings and the main field windings. The rotor may have a first end attached to the engine power output shaft and a second end adapted to deliver mechanical power from the engine to the transmission.