From ancient times, people have been trying to find out the perfect energy producing machine. For that purpose, brilliant minds put themselves to work and researched the most sophisticated mechanical machines ever. Until nowadays, no such machines have broken through the filter of time, and no such wonderful inventors are known to have made the over unity device.
Still, there is a doubt: it seems certain interest groups from the 20th century and today still have a problem with ones who invent anything that goes very efficient, and reduces the consumers’ energy costs, free energy machines included. If you have been paying attention, there are a lot of interesting and breakthrough inventions that you only hear about, but that don’t succeed getting out on the market, or are proven suddenly, with no presentable evidence, that they are fakes.
All I know is that there is no smoke without fire, and there are a lot of non-interested people claiming the same thing.
For example, this man from Serbia, Veljko Milkovic, appears to have invented a device that does overunity: it outputs more energy than inputted, apparently violating Newton’s Third Law of Motion: “For every action there is an equal and opposite reaction.”
It seems Veljko’s machine uses the gravitational force for its power source, thing that others have also claimed.
“This gravity machine has only two main parts: a massive lever and a pendulum. The interaction of the two-stage lever multiplies input energy into output energy convenient for useful work (mechanical hammer, press, pump, transmission, electric generator…).”
More details are on Veljko’s site.