Well, though a way for such things has never been discovered, I'm giving my idea for a perpetual motion device, though it was originally thought up as a device for overunity.

It's pretty simple - attatch a generator directly to an electric motor, then run a cord to the electric motor, and hand crank the generator to start it.

Anyone else have an idea for a perpetual motion device?

I don't think that would work as energy would be transferred to heat (via friction) and sound inside the generator. This would mean that you would run out of energy in the system so it would eventually stop. This is similar to the theory of a solar panel powering a light bulb, but obviously the light bulb gives off heat energy which is not taken up by the solar panel.

rvalkass is right, friction in the system would eventually stop it. No offense but so many poeple have tried inventing a perpetual motion device that I doubt whether it is at all possible with current technology and I doubt whether it'll be developped on this board lol.

In my opinion if you're trying to develop a perpetual motion device your best bet probably involves vacuums, superconductors and magnetic fields. but as I said before... many many poeple have tried and failed... I doubt somebody on here will succeed, of course I could be wrong

They've already succeeded - in space that is. Every satillite in space is in perpetual motion. It's impossible to do it here on earth, I belive. Somebody said it in the Mythbusters forums over at the discovery channel, and those who post there are usually very smart people, but sometimes not.

i thought perpetual motion on earth was already created with that box that had hinges on the edges. I saw a demonstration, but it could have just been powered by electricity to show a theoretical idea.

Before I even read your reply I was going to say gravity and orbit, though I hesitated and still am unsure of this because gravity is the same as falling towards something slowly while circling it, and satellites will eventually collide with something unless some other force moves them away from the planet/gravitational pull they are orbiting.

The satellites in space use solar panels to gather power to correct their orbits, otherwise they would crash, thus since they use an external power source they are not a "perpetum mobile". In theory yes, every satellite is a perptual motion device but as so often, reality and theory don't quite match.

Yes this idea is pretty simple, the biggest thing that will stop it is the efficiency of the motor and generator. While motors and generators are fairly efficient, they are not 100% efficient, due to friction mainly. To explain this in basic terms, let's assume both the motor and generator have an efficiency of 90%, I think it is actually less than this but it will do for this example.

Let's assume the motor consumes 1000 watts and the generator output is 1000 watts. Sounds like a nice balance doesn't it?

The fact is, due to being 90% efficient, the generator will require a motor of around 1100 watts to to drive it sufficiently for it to output 1000 watts. So now we need a bigger motor to drive the generator, but wait a minute, as the motor is also 90% efficient, we need around 1200 watt motor to drive the generator. That means we need a bigger generator to drive the bigger motor, which means we need a bigger motor to drive the bigger generator... ARGH! See the problem with this idea?

If both the generator and motor were 100% efficient, this might work, but alas, that is not the case.

... and it never will be. Even things in space don't move indefinately (they could, in theory, but they don't). The pull of gravity from stars and planets can either slow down or speed up their movement, and objects in space (even just space dust) will slow it down. If there was a perfectly empty vacuum, however, then yes, said object in space would move indefinately.