Magnetism: Can Magnets Power Devices?

[Denken]

I know that a magnet passing through a coil will create a current in the wire. So what is stopping us from using magnets to power things?

 

[Vagn]

I know that a magnet passing through a coil will create a current in the wire. So what is stopping us from using magnets to power things?

We do! Well sort of, that's what happens in most power stations, the working fluid is heated up by burning fossil fuels etc. and turns the turbine, which contains a large magnet to produce an electric current. We also use it to light up the lamps you get on bicycles etc. If you mean why don't we just use a magnet? That's because you need to do more work lifting the magnet up then you get out of dropping it through the coil.

 

[Denken]

but it doesn't have to be dropped
it can be pushed sideways

 

[Vagn]

Then you would have to do work to move it across, which again would use more energy than would be induced in the coil.

 

[Curl]

I know that a magnet passing through a coil will create a current in the wire. So what is stopping us from using magnets to power things?

Other than money, nothing.

Its being done every second around the world.

 

[Hassan Javed]

it will consume more energy as to move megnet , than the energy it will give as output.

 

[MagnetDave]

I know that a magnet passing through a coil will create a current in the wire. So what is stopping us from using magnets to power things?

Nothing. We do it all the time in alternators and some generators.

It's not perfect, since less than 100% of the force used to move the magnet is turned into electricity, but it works pretty well.

 

[K^2]

but it doesn't have to be dropped
it can be pushed sideways

There is a force, similar to friction, when you move a magnet past a coil through which a current can flow. So when you move a magnet past a coil to drive current, you have to have something continuously pushing on the magnet. Simplest example is a generator. You crank up the arm, and you get current flowing, but if you've ever tried that with a real generator, you know that it takes quite a bit of effort to do.

 

[cragar]

That's how they produce hydro-power in a dam.

 

[K^2]

That's how they produce power pretty much anywhere. Other than solar panels, I'm not aware of any other method of industrial-level power production that does not involve magnets. Though, they aren't necessarily permanent magnets.

There are also fuel cells, chemical batteries, and thermocopules, but none of these are used on particularly large scale.

 

[cragar]

good point

 

[Denken]

ok so i know that there is force between a magnet and a wire with a current already in it. So tell me if I am misunderstanding, but then are you saying that that force also applies when the magnet creates the current in the wire?

 

[K^2]

At the exact moment you start moving the magnet, there is no current, and there is no force. However, since there is no current, the coil isn't outputting electrical work, either. For coil to do electrical work, current must be non-zero, but then the force on the magnet is non-zero, and then the work you do on the magnet is non-zero. If there is no friction or resistance, the two works are exactly equal. In realistic case, the work you do on the magnet is greater than the electrical work the coil does on whatever you connected it to.

 

[Denken]

im just wondering for just a magnet moving through an uncharged coil, the charge created is creating a force back on the magnet
right?

 

[nismaratwork]

im just wondering for just a magnet moving through an uncharged coil, the charge created is creating a force back on the magnet
right?

Let me ask this flat out: Are you still trying to think of a way to extract energy directly from EM fields (a la incredibly long antennae or the like), or trying to understand some other principle?

Any, it SEEMS like you're asking whether or not the motion of a magnet past the kind of coil mentioned earlier (I think you're mixing some terminology) produces a reciprocal force on the rear of the magnet... which would propel the magnet forward.

NO.

If you're thinking of a coil-gun, then it's an uncharged slug in a coil, where the COIL is the magnet. If not that... I have no idea what the hell you're thinking.

 

[JaredJames]

I can see this becoming a discussion on a PPM.

Just from what I've read here, I can come up with three 'designs' for such a device (naturally won't work, but I can see them as something someone could be thinking of and trying to make).

 

[Denken]

I've been studying a few things related to this so I am not just asking a bunch of question's and yes it does related to a ppm, my idea would be effectively a ppm however at a point the container would weaken to the point of breaking and stop it, so it is not a true ppm.
...
Since i don't have the means to test my idea I've brought it here to test the idea with people that i assume know more about it than i do.
...
there are two ideas i have that i believe would virtually be perpetual:
1. having an open top rectangular container where the walls and floor are lined with magnets all but one of the smaller walls having either have + or - facing inward, and that one other wall being the opposite of the others. Then with a three sided "cart" lined with magnets facing outward and opposing, creating a levitating effect. Then having a magnet inside the cart facing in such a way as to repel from both of the smaller walls of the container. All within a vacuum.

2. is the same basic idea except with a circular track instead of a rectangular one, and instead of one "cart", having two that start next to each other and when released would bounce back and forth along the track.
...
these are not to create energy they are simply "perpetual machines" (possibly)
If you think you see a flaw with this ( other than in breaking down overtime due to a joint failure related issue ) i would love to hear about it.

 

[JaredJames]

I've been studying a few things related to this so I am not just asking a bunch of question's and yes it does related to a ppm, my idea would be effectively a ppm however at a point the container would weaken to the point of breaking and stop it, so it is not a true ppm.

That topic is banned here. PPM don't work. Period. (And for more than simply having parts break down.)

there are two ideas i have that i believe would virtually be perpetual:
1. having an open top rectangular container where the walls and floor are lined with magnets all but one of the smaller walls having either have + or - facing inward, and that one other wall being the opposite of the others. Then with a three sided "cart" lined with magnets facing outward and opposing, creating a levitating effect. Then having a magnet inside the cart facing in such a way as to repel from both of the smaller walls of the container. All within a vacuum.

2. is the same basic idea except with a circular track instead of a rectangular one, and instead of one "cart", having two that start next to each other and when released would bounce back and forth along the track.

Both similar to ideas already out there. They both have a number of flaws. Number 2 for example would reach an equilibrium point and stop - assuming I'm picturing it right. Number 1, I'm not entirely sure what you're describing, but without an external source of energy (which neither has) they cannot function as perpetual machines.

To have a perpetual machine, you need an external energy input to maintain motion. PPM in the form of over unity devices simply don't work.

Number 2 sounds like something already on the market but with a battery powered electromagnet controlling things.

 

[nismaratwork]

The other flaw is that perpetual motion WOULD require infusions of energy... you can't just ignore that Denken. Oh, and yeah, so SO banned topic I feel vaguely radioactive being close to this thread and you.

 

[russ_watters]

Denkin, those are not perpetual motion machines, they are just devices that can run for a long time. Newton's first law tells us an object will move forever if it isn't acted on by an outside force, so obviously it is possible to set an object into essentially perpetual motion - it can be done with an orbit, for example. But that's not a machine. A perpetual motion machine is a machine that violates one of the laws of thermodynamics, typically for the purpose of creating free energy.

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

 

[Archosaur]

If I could just jump in here before the hammer falls...

Denken, when you think of magnets in terms of energy, think of it sort of like gravity. Sure, something can gain energy by "falling" toward a magnet, but there can be no cyclical process unless the object is "picked back up," which takes at least the same amount of energy as is generated.

Also, when inducing currents with a magnet, there is a force that opposes the movement of the magnet. The electrical energy produced is AT MOST equal to the force opposing the magnet, times the distance it moves. i.e. it takes more energy to push the magnet through the coil than you get out in the form of a current.

 

[berkeman]

Thread closed for now.