Science Nerds Assemble

[ChroniC]

Now, I never makes these types of threads because I know If I've thought of it, then someone smarter already has and it must be wrong, but I can't in this case for the life of me see why this doesn't work, and I want you guys to tell me why. (I've googled it, but can't find the info I need)

I'm always when bored, trying to think of ways to making a perpetual motion machine. (I know impossible) and have been recently trying to think of ways to make use of mavity as an energy source, but then this occurred to me.

If you took a simple basic electromagnetic generator, I.e a magnet in a coil, and spin it (you get a current as far as I remember).
I assume you don't get as much electrical energy out, as the energy put in to spin the actual magnet. However, if your in zero mavity, e.g space, would the magnet not spin indefinitely, giving you endless current, and endless electricity.

That's the basis of my stupid idea, now why doesn't it work, and then lets say we could tether to space, could we not just have 1000s of generators floating in orbit?

OCUK, shoot me down!!

 

[Tephnos]

You can only get out as much energy as you put into the system. Perpetual motion is not 'generating' energy, it's just conserving what it has.

Essentially, it would violate the laws of the conservation of energy.

 

[ChroniC]

You can only get out as much energy as you put into the system. Perpetual motion is not 'generating' energy, it's just conserving what it has.

Explain how that applies, when the magnet never stops spinning. Regardless of that law??
The reason it confuses me, is that planets never slow down, the earth never stops spinning, so where is that energy coming from?

Even so, if I'm wrong about that, stick a solar sail on the end of the magnet and let the solar winds (which never stop) spin the magnet. Then your getting energy from the sun.

 

[daz]

The maget's rate of rotation will slow down as you take energy out of the system.

 

[Mobius 1]

i heard the earth might be slowing down, and possibly might spin the other way one day

 

[ChroniC]

The maget's rate of rotation will slow down as you take energy out of the system.

Even though its not touching anything, as it's free floating in zero mavity. Are you telling me that there is a loss of energy through the vacuum? I can understand that by friction, but its a frictionless environment.

 

[Jonnycoupe]

An alternator slows down an engine when you put on the heated rear window...... same principle.

 

[Reaper 392]

i dont see how mavity really affects the electromagnetic generator in the first place, its air resistance, and the magnetic forces from the generator that slow the magnet down, not mavity

if your thinking about perpetual motion, the only thing that will come close is working out how to take the thermal energy from the air and turn that into useful energy.

 

[ChroniC]

An alternator slows down an engine when you put on the heated rear window...... same principle.

Does that principle have a scientific name? Or is that just rubbish?

 

[Clav]

Even though its not touching anything, as it's free floating in zero mavity. Are you telling me that there is a loss of energy through the vacuum? I can understand that by friction, but its a frictionless environment.

If it is free floating in a vacuum then how is it a generator? And not just a spinning object in space?

 

[ChroniC]

i dont see how mavity really affects the electromagnetic generator in the first place, its air resistance, and the magnetic forces from the generator that slow the magnet down, not mavity

if your thinking about perpetual motion, the only thing that will come close is working out how to take the thermal energy from the air and turn that into useful energy.

Ignore mavity, I took it out of the equation, that was just a side thought that lead me here.
What I'm saying is that something set in motion, i.e spin, in space never stops. The principle of an electromagnetic current is a magnet spinning in a coil of wire, apply the never stopping magnet to the equation, and you have a never ending current!

If it is free floating in a vacuum then how is it a generator? And not just a spinning object in space?

I was under the poor basic school science assumption that a magnet spinning in a coil of wire creates current via electromagnetic fields. Freefloat a magnet inside a cylinder of wire then set it off spinning, I also though that since it has no friction, it will not stop spinning like it would on earth.

 

[Liampope]

mavity =/= friction. Putting your generator in 0g does not remove friction from bearings, etc. Also, you are not just turning a generator against friction anyway - even though the rotor is not physically touching the stator, it's motion is resisted by electromagnetic force proportional to the current drawn from it. Not gonna work.

 

[Tephnos]

Remember, the vacuum of space is not a perfect vacuum either. Also, as far as I'm aware, eddy currents would probably disrupt the system eventually (Lenz's law).

 

[Pixel]

The reason it confuses me, is that planets never slow down, the earth never stops spinning, so where is that energy coming from?.

I assume that energy is left over from the formation of our sun and solar system, a huge explosion of some sort if current theories are to be believed.

 

[jak731]

Does that principle have a scientific name? Or is that just rubbish?

Magnetic force, aka Lorentz force will slow the magnet down when current is drawn from the coil around it. Magnetism travels just fine through a vacuum because the photon is the force carrier.

 

[ChroniC]

mavity =/= friction. Putting your generator in 0g does not remove friction from bearings, etc. Also, you are not just turning a generator against friction anyway - even though the rotor is not physically touching the stator, it's motion is resisted by electromagnetic force proportional to the current drawn from it. Not gonna work.

Wouldnt require bearings. Could be done with a solid magnet and a coil of wire.
What do you mean by motion is resisted. Would the electromagnet force applied to the actual coil, have its own resistance to the coil itself?

 

[Tephnos]

The reason it confuses me, is that planets never slow down, the earth never stops spinning, so where is that energy coming from?

Even so, if I'm wrong about that, stick a solar sail on the end of the magnet and let the solar winds (which never stop) spin the magnet. Then your getting energy from the sun.

Well, that's the thing. Nothing in space will last forever. The earth will eventually cease to orbit the sun, it will eventually slow down, etc. It just wouldn't do that for a very long time.

As for your second idea, the 'perfect' energy source would be a 'sail' of satellites covered in solar panels surrounding the sun. Can't get any better than that.

 

[anything I don't mind]

There is already perpetual motion machines I have seen them with my own eyes.

http://www.youtube.com/watch?v=us7YB7eiOeQ

check out the over unity videos on youtube, many machines exists that run on magnets and charge a battery up while using it and the machine can run a light bulb etc for ever. Well as long as the battery and the mechanics of the device hold up.

http://www.youtube.com/watch?v=4O9ectXC3Sk

http://www.youtube.com/watch?v=fRyksa-7Bcc

There are tons of examples.

google: bedini motor

http://www.youtube.com/watch?v=uHh5AqQ4_xw

 

[Freefaller]

Does that principle have a scientific name? Or is that just rubbish?

It's already been stated - it's a key law of physics, the conservation of energy. Energy can neither be created nor destroyed - it only transfers into a different sort.

So the fact that it's spinning, by drawing electricity from it, it'll slow down and eventually stop as you take energy out of the system.

 

[Dr.EM]

Does that principle have a scientific name? Or is that just rubbish?

Inductive braking? It's a very well known effect of electric motors/generators and a widely understood electromagnetic principle! A motor wired onto a H-bridge will be able to inductive brake by effective connecting of the output terminals together, in this scenario the motor tries to generate infinite current (= infinite power) into the short circuit load and this means it brakes hard, useful in some applications. Try it, get a small DC motor, spin it, then spin it with the output shorted or under heavy load, harder isn't it?

Electric vehicles use the effect where the braking, instead of dumping energy into a short circuit, instead pumps the energy back into the vehicle batteries. This is called regenerative braking and helps makes the vehicle more efficient in start/stop traffic.