How to harness energy from magents

[debian0001]

Can someone give me a good guide or book.. I would like to create something like this and power something stupid... What would I need to harness power from this.. I don't know much but I want to learn.

http://www.youtube.com/watch?v=27-3TKKXsm4

 

[masteryoda34]

http://en.wikipedia.org/wiki/Laws_of_thermodynamics

 

[Matt1970]

In layman’s terms it takes more energy to make the magnets than the magnets will ever be able to produce.

 

[Sheep221]

He didn't measure how much energy it generated, but I assume that using computer fan won't create much high voltage, but it could be used to charge phones in the case of blackout.

 

[Jeff7]

Magnetic fields aren't some kind of energy that can be sucked out of the magnet like a battery. It's more along the lines of how you can use Earth's gravity for power:
Hydroelectric power does use gravity - but the water's got to get into the basin in the first place before it can then fall over a turbine, which is of course done by solar energy, via the water cycle. In that case, you can only get out, at most, the amount of energy that was put into the water to move it up to the higher elevation in the holding basin above the turbine.
What makes magnets special is that they can influence electrons. Push a wire through a magnetic field, and the electrons will want to move a certain way as they pass through the field. If they're in a conductive material, this will permit the flow of charge, which is current. But while you're pushing the wire through the field, the moving charges will puff out their own little magnetic fields to try to return themselves to the original field state. If the electrons have nowhere to go though, if the wire isn't connected to any kind of load, then they can't move much, so their resisting magnetic field is very minimal. But if there's a load attached, they will resist more intensely - this is why a generator turbine needs to be forcibly pushed to keep spinning, and it's also (a small part of) why these "perpetual motion machines" can't exist.


More on magnets in general: They've got a field that acts over a large distance, at least when compared to the electric field, which is what keeps matter from passing through other matter. That field works over very short distances, such that we perceive it to be a sudden impact.
If you looked at a magnet on a different scale, it would react in very much the same way: Start 5 miles away from a small magnet's north pole, and walk toward it while holding another magnet with its north pole facing toward the stationary one. The vast majority of your journey will be quite uneventful, with the exception of the last few inches of the trip, when you are finally close enough to feel the magnet's effects. The electric field's range of influence is simply very small.
(And then you've got gravity, which operates over very large distances. Maybe they're all even related...somehow.)

In either case, magnetic or electric, it's still just a static field, and it's not some kind of infinite energy source that the magnet is stubbornly trying to keep to itself.

 

[Mark R]

Can someone give me a good guide or book.. I would like to create something like this and power something stupid... What would I need to harness power from this.. I don't know much but I want to learn.

http://www.youtube.com/watch?v=27-3TKKXsm4

This device is very simple.

You need a conventional DC brushless motor fan. Attach a CD to it, and then glue 4 magnets, with N pole facing outwards to the CD.

Then take 2 extremely fine wires (so fine, they are difficult to see, and to fine to be seen by a cheap camera phone), and attach them to the fan leads. Use a switch to connect your thread-like wires to a 12V power supply.

Using a bar magnet with S pole facing away from you, use it to spin the disc by attracting the magnets on the CD.

Once you have got the disc starting to spin, turn on your switch. The fan motor will take over and keep the disc spinning.

To stop the spin, simply move the magnet away from the CD and turn off the switch. You don't need to move the magnet away - but it looks better if you do.

 

[WildW]

I had assumed the magnet in his hand was an electromagnet driven by an alternating current with wires going up his arm. So many possibilities, but definitely not what it appeared to be.

 

[Matt1970]

I had assumed the magnet in his hand was an electromagnet driven by an alternating current with wires going up his arm. So many possibilities, but definitely not what it appeared to be.

It actually works like he shows. You can build one yourself. And there will actually be current on the wire leads of that fan. The problem is the total energy something like that will ever be able to produce over its lifetime will never equal the energy it took to make those magnets. It's not perpetual motion or free energy. If it were a certain amount of current could be looped back to keep the magnets fully magnetized.

 

[Mark R]

It actually works like he shows. You can build one yourself. And there will actually be current on the wire leads of that fan. The problem is the total energy something like that will ever be able to produce over its lifetime will never equal the energy it took to make those magnets.

Magnets do not release energy slowly or "discharge" because you've drawn energy out of them.

Magnets release energy when a piece of metal (or another magnet) is attracted to it. The magnet is recharged when you pull the metal off.

Permanent magnets do "fade" very slowly, but this is not because you've drawn energy out, but because of random molecular motion gradually destroying the magnetic orientation.

 

[Matt1970]

Magnets do not release energy slowly or "discharge" because you've drawn energy out of them.

Magnets release energy when a piece of metal (or another magnet) is attracted to it. The magnet is recharged when you pull the metal off.

Permanent magnets do "fade" very slowly, but this is not because you've drawn energy out, but because of random molecular motion gradually destroying the magnetic orientation.

Magnets don't recharge themselves. Every time a magnet attracts another piece of metal or another magnet it loses a tiny fraction of its magnetic ability. The magnets in that demonstration aren't having energy drawn directly out of them. They are being used to produce work. That work can be converted into electricity. The thing is the amount of electricity that magnets can produce through work like that will never equal the amount of electricity it took to make the magnets. Every time that magnet goes by another magnet it loses a very tiny amount of its magnetic ability and eventually will no longer be able to the work, in that case spinning the CD/fan it is on. Those magnets will now need to be re-magnetized and that will take more electricity than the machine ever produced to begin with. If it didn't, you would have perpetual motion.

 

[Mark R]

Every time that magnet goes by another magnet it loses a very tiny amount of its magnetic ability and eventually will no longer be able to the work, in that case spinning the CD/fan it is on. Those magnets will now need to be re-magnetized and that will take more electricity than the machine ever produced to begin with. If it didn't, you would have perpetual motion.

Absolute nonsense.

 

[Matt1970]

Absolute nonsense.

Nevermind. I don't even think the centrifugal force will be enough to overcome the opposing magnets force to keep it spinning.

 

[Red Squirrel]

You need energy to move the magnet, and the more energy is being produced, the more drag it will cause thus require more energy to turn it.

Take a small DC motor, hook it up to a dremel tool. Turn it on, short the motor out or put a heavy load on it, the dremel will be forcing. You can also rig something up so you can crank it, and see that it will be harder to crank as you draw more watts from it.

 

[Born2bwire]

Magnets do not release energy slowly or "discharge" because you've drawn energy out of them.

Magnets release energy when a piece of metal (or another magnet) is attracted to it. The magnet is recharged when you pull the metal off.

Permanent magnets do "fade" very slowly, but this is not because you've drawn energy out, but because of random molecular motion gradually destroying the magnetic orientation.

I agree with Mark R. The magnetic field is a conservative field. When a piece of metal is attracted and moves towards a magnet, the energy stored in the magnet decreases as it does work on the object. But this same energy is reinvested into the magnet when you pull the metal away from the magnet (from the work you do to counter the force of the magnetic field). Ideally, this process would proceed for infinite iterations but a ferromagnet works on the principle that the small magnetic domains inside the material are aligned in a common direction. The directions of these domains can revert to a more random pattern, particularly if they are exposed to physical or thermal shock, but they can be very stable, depending on the material. The lowest energy state of a ferromagnet is being overall unmagnetized.

 

[Biftheunderstudy]

Everyone repeat this mantra:

Magnetic Fields do no work!!

Basic tenant of E&M.

Edit: I should point out, I'm being (somewhat) sarcastic here as this "tenant" is kind of slippery.

 

[Born2bwire]

Everyone repeat this mantra:

Magnetic Fields do no work!!

Basic tenant of E&M.

Edit: I should point out, I'm being (somewhat) sarcastic here as this "tenant" is kind of slippery.

This is true, but the caveat is that we always have an electromagnetic field where the electric field can do work. The magnetic and electric components of the EM field change depending upon the frame of reference. What I mean by this is that we can have a lab frame where we have only magnetic fields but there is obviously some work being done when an object is pulled into the magnet (like the case of two parallel wires with constant currents). But from the perspective of the object, it will see an electric field that exerts the force that gives rise to work due to the transformation of the lab frame's magnetic field into an electric field in the moving frame of the object.

Griffith's electrodynamics text has a section about this where he takes the case of the electrons in two current carrying parallel wires. He shows explicitly how the magnetic field is transformed into an electric field in the frame of the electron that gives rise to the same attractive force that is seen in the lab frame due to the magnetic field.

 

[SecurityTheatre]

Wow, perpetual motion machines are so much bunk. You can make something *look* that way all you want, but the power comes from somewhere. That rig has a non-trivial amount of drag. Any other power comes from an external source, whether it's the hand moving toward the device, or something more hidden like a motor, it isn't just generated out of the air.

And no, magnets do not "deplete". Permanent magnets are not losing magnetism from attracting things. They can, however, lose magnetism from being dropped, or subjected to repeated impacts.

 

[Matt1970]

Wow, perpetual motion machines are so much bunk. You can make something *look* that way all you want, but the power comes from somewhere. That rig has a non-trivial amount of drag. Any other power comes from an external source, whether it's the hand moving toward the device, or something more hidden like a motor, it isn't just generated out of the air.

And no, magnets do not "deplete". Permanent magnets are not losing magnetism from attracting things. They can, however, lose magnetism from being dropped, or subjected to repeated impacts.

I was under the understanding that magnets generate a small amount of heat when attracted to another magnet or metal and that heat slowly destabilizes them.

 

[SecurityTheatre]

I was under the understanding that magnets generate a small amount of heat when attracted to another magnet or metal and that heat slowly destabilizes them.

No.

Magnetic forces are much like gravity. There is a "potential energy" that is consumed from falling into a magnetic field, just as there is from falling into a gravity well, but it is not a physical property that can be measured.

Some people ask "how do magnets generate seemingly endless energy to inflict forces on objects?" But this is a bit like asking "how does this hill generate seemingly endless energy to cause things to continually roll down it?"

The act of falling toward a planet does not impart any energy onto the planet, in the same way that the act of being attracted to a stationary magnet does not impart any energy into the system (other than potential energy), in a relative sense.

 

[Matt1970]

No.

Magnetic forces are much like gravity. There is a "potential energy" that is consumed from falling into a magnetic field, just as there is from falling into a gravity well, but it is not a physical property that can be measured.

Some people ask "how do magnets generate seemingly endless energy to inflict forces on objects?" But this is a bit like asking "how does this hill generate seemingly endless energy to cause things to continually roll down it?"

The act of falling toward a planet does not impart any energy onto the planet, in the same way that the act of being attracted to a stationary magnet does not impart any energy into the system (other than potential energy), in a relative sense.

I am confused. Are you saying you can't measure the amount of potential energy consumed from falling into a magnetic field or the field itself? You can use a magnetometer to measure the strength of magnetic fields.

 

[piasabird]

Check out this professor in Motreal area in Canada. He builds things with magnets and has some videos about urban solar powered mobility vehicles.

http://www.youtube.com/watch?v=QaVwhBOq8lw&list=PLC57A2E5D89FB1740

This guy is interesting. He seems quite smart.

He also believes that aliens seeded many different earths or planets.

 

[Gibsons]

I am confused. Are you saying you can't measure the amount of potential energy consumed from falling into a magnetic field or the field itself? You can use a magnetometer to measure the strength of magnetic fields.

He's saying that it's similar to having a big boulder on top of a hill. Yes that's potential energy, but it's in no way perpetual. Unless you've got Sisyphus to roll the rock back up perpetually.

 

[yhelothar]

He's saying that it's similar to having a big boulder on top of a hill. Yes that's potential energy, but it's in no way perpetual. Unless you've got Sisyphus to roll the rock back up perpetually.

It is perpetual if it's orbiting the planet.
But harnessing that kinetic energy would deorbit it.

 

[piasabird]

If you had a magnetic drive that spins at 2k and slows down over an exended period of time due to centrifical force, then it could be creating power even when coasting just from the magnetic field created. Or you could keep it going at a steady rate buy using pulses instead of constant power.

Think of the perpetual movement of waves in the ocean. Does moving ships back and forth through the waves make the earth slow down? Same goes for wind turbines. How comes the earth's orbit does not decay when we harness the power?

 

[Biftheunderstudy]

Basically, yes, waves (really tidal forces) are slowing the Earth's rotation. This is a measurable effect, and you can also see it in the recession of the moon's orbit. Do ships and wind turbines change the Earth's rotation? Sure. But the Earth has a *lot* of angular momentum...the effect is very small.

Very large earthquakes also change the earth's rotation.

Thermodynamics and conservation of energy, they are a thing.