US Patent 9515597 Electric machine

An electric machine has a primary mechanical output or input, a plurality of electric sub-machine rotors each having an output or input shaft, a plurality of electric sub-machine stator magnets proximate the rotors, a drive train connecting each of the output or input shafts of the plurality of electric sub-machine rotors to simultaneously drive, or be driven by, the primary output shaft. Each sub-machine is selectively engaged or disengage depending on machine power.