# Dampering a magnetic field

1. Jan 11, 2008

### rneville

Hi,

I have a real world practical problem I need to solve. Assume you have a magnet of your choice and nearby (say 1 inch away) a piece of metal of your choice that is being attracted to the magnet. Is there some material / substance that can be easily placed between the magnet and the piece of metal that will diminish or ideally, cancel the attractive force? The only requirement of this problem is that the 'material' needs to be easily inserted and removed with little energy expended. What magnet / metal combination would provide the greatest attractive force without the 'material' but offer the largest reduction in force when intercepted with this 'material'?

Ok so you can smell from my terminology that this is not my field - I'm in the computer side but this truly is a problem that needs a solution.

Thanks for any suggestions!

rob

2. Mar 10, 2008

### navy2kq

the millenia problem!

Hi rob it seems we both have the same question... What you want to do is to be able to use the magnets force po push only at demand (like an electirc magnet would do by turning on and of) there seems to be some sollutions to the problem see some other posts on this forum about magnetic insulation seems some silicon-steel and mu coatings would do the job of insulating ... The energy used to start-stop(insulate/release) it are unknown to me.

My idea was to build a system similar to a basic inner combustion engine like any car engine, by compressing and then exploding the carburant(insulating and realeasing the magnetic field)... similarily if you can turn of and on a magnet's power by using a "short circuitting" or insulating material would mean that such an engine is possible... if shortcircuiting the magnet doesn't require exactly the same amount of energy gained from the "reaction" you might just be onto something. If this problem is solved, very efficient "magnetic power" could be harnessed.

The problem you try to find a sollution to is the basic problem why there arn't any such egenerators for the moment... I think :)... There's got to be an issue with the energy inserted and gained from the system (allways was).

Btw I'm in the computer industry aswell :D, maybe that's why I can better relate to your problem :D

E=F*d (Energy = Newton*meter for instance) this means that if you only measure this energy after the magnets are N to N(or S to S for instance) brought together you will measure an energy... Given the fact that you actually need the same amount of energy to put into the system to bring the 2 magnets that close is equal to the released energy it all goes to 0. Now if you somehow are able to stop/start(insulate/release) the magnets property at will you can create magnetic power electric generators or whatever else... since this is a nobel prise question and quest I don't think the energy needed to insulate the magnet can be lower then the one produced by releasing it(at least not with our current knowledge). I think that quantic physics will some day solve the riddle and understand how to really harness this mesmerising "power" or end this quest for the physics Graal.

The problem with this is that you have to use some sort of another energy to do it because the laws of thermodinamics state clearly **** in **** out. So you need to find some sort of another energy that is very cheap expendible or anything else to do so, in this case probably chemical energy of some sort could be used but I could't tell you exacly what. Just try the sollution wit silicon steel and mu... As I said the probability that even with this materials you will need es much energy as you get out just to insulate it is very high or dare I say for sure... As you see allways something needs to get used somewere... I think everybody just hopes to actually use zp energy or some other "astral" powers we don't know about and thus go on and on in their pursuit of the modern Graal...

Hope this helps,

paul

PS: I'm not a pesimist just making sure that I have some reality to base my dreams on...

Last edited: Mar 10, 2008
3. Mar 10, 2008

### TVP45

You can always shield the magnet with a high permeability material. The problem is that you will use energy in doing so. No free ride there.

4. Nov 17, 2008

### unscientific

put a magnet in between them.

5. Nov 25, 2008

### Daynosdr

I have no scientific evidence to back up my point, though I have practical application.

There is a material which can be put in place between a magnet and a ferrite, to cancel (or at least reduce) attraction.

The Material is found in hard drives on the really powerful magnets (the pieces that secure the magnet to the casing.) I was looking for the material upon noticing the property. If you do figure it out please let me know.

Thanos
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Mechanical Engineering
University of Ottawa