A basic principle in Physics, at least in the realm of our everyday size, energy is conserved. That means that perpetual machine is an impossibility. However, here are two videos on youTube which claims to produce free energy with over millions of views.
Power is not just voltage. Power is voltage times current. By increasing the number of turns in the rotor, we can get a higher induced e.m.f, ie voltage. But once a load is applied, there will be a current and the current will generate a force to oppose the motion and hence stopping the rotor. So far, no one has just demonstrably show a perpetual machine, not to mention extracting additional energy out of the machine.