Over-unity

Look for the "over-unity" ratio when calculating energy output versus input as a proof of free energy.

Source: wiktionary

The system behaves as an over-unity device producing energy from atomic hydrogen by a repeated dissociation and recombination of hydrogen atoms. MAHG tube contains a vacuum tube filled with hydrogen at 0.1 atm and cooled by water.

Source: wiktionary

"The Potapov device," the experimenters reported ruefully, "did not show any evidence of over-unity performance in our tests. We can find no explanation for the failure of this Potapov device to perform as reported (300% over-unity)."

Source: wiktionary