"why does it matter"! - the fact that you ask that tells me all I need to know! Forget any calculations, forget any comments above, test the theory. Connect your "engine" to a small alternator, it can turn that can't it? Feed that to a car battery, connect a 12v-240 transformer to the battery and plug the drill into that. Also plug the drill into the mains, split the wires so both sources feed the drill. Turn on the mains and the drill, leave the drill on and turn off the mains. If you are correct the "engine" should run fior ever with no power input. Tada, nobel prize!