I met an inventor who told me he had submitted a patent application which had been rejected by the PTO beacause it was considered a perpetual motion device.( not allowed)
The textbooks on dc motors always warn not to remove the resistance from the field coils because if you do,the dc motor will accelerate and self destruct from the centrifugal forces.WilburDuncan (the inventor) said he'd devised a way to extract the energy from it before it self destructed.-much like an inertia motor for auto propulsion.
This sounds like a plausible thread for consideration.
Robert