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Author Topic: Are partial monopoles possible?  (Read 6864 times)

DreamThinkBuild

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Are partial monopoles possible?
« on: August 08, 2014, 02:59:19 AM »
Hi All,

Not sure if this has been posted before or old news but I found this out by accident when trying to clean my desk. A stack of magnets slammed into a 1/4" thick iron rectangle, when checking the magnets for damage I noticed that a compass nearby the needle constantly pointing at it no matter the direction of the plate. It only flipped when it got near the magnet stack.

I thought it was pretty odd so I grabbed the magnet tester and it read south on both sides and ends. By bringing the south side of another magnet near it, it repelled on both sides and ends. The magnet stack top will read north but everywhere else on the plate is south. If the south side is brought close to the iron it will stick but otherwise if slightly away from surface it will repel.

This should be easy to replicate all you need is a stack of magnets, a thin iron plate and compass or magnet tester. Another magnet also to show that it's repelling on both sides. It may work with steel also, have not tried yet.

I'm a little stumped why the plate is acting like a monopole, hope someone else can replicate to verify if I'm not just making a mistake somewhere. The repelling of a south facing magnet on each side is pretty convincing to me but I'd like others input.
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MarkE

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Re: Are partial monopoles possible?
« Reply #1 on: August 08, 2014, 04:07:35 AM »
Quote from: DreamThinkBuild on August 08, 2014, 02:59:19 AM
Hi All,

Not sure if this has been posted before or old news but I found this out by accident when trying to clean my desk. A stack of magnets slammed into a 1/4" thick iron rectangle, when checking the magnets for damage I noticed that a compass nearby the needle constantly pointing at it no matter the direction of the plate. It only flipped when it got near the magnet stack.

I thought it was pretty odd so I grabbed the magnet tester and it read south on both sides and ends. By bringing the south side of another magnet near it, it repelled on both sides and ends. The magnet stack top will read north but everywhere else on the plate is south. If the south side is brought close to the iron it will stick but otherwise if slightly away from surface it will repel.

This should be easy to replicate all you need is a stack of magnets, a thin iron plate and compass or magnet tester. Another magnet also to show that it's repelling on both sides. It may work with steel also, have not tried yet.

I'm a little stumped why the plate is acting like a monopole, hope someone else can replicate to verify if I'm not just making a mistake somewhere. The repelling of a south facing magnet on each side is pretty convincing to me but I'd like others input.
Everything in those pictures looks normal to me.  The black thing is an iron plate, right?  In each case where the detector indicates S, the S end of the stack looks to have a shorter reluctance path to the end of the detector than the N end of the stack.
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tinman

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Re: Are partial monopoles possible?
« Reply #2 on: August 08, 2014, 05:50:35 AM »
A Temporary monopole field can be formed around steel sphere, thus giving the result in  that the steel sphere is being repelled by the magnet, insted of being attracted to it.
Might be handy in a SMOT type device.
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DreamThinkBuild

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Re: Are partial monopoles possible?
« Reply #3 on: September 20, 2014, 03:25:09 AM »
Hi MarkE, Tinman, All,

Been doing some more experiments with polarizing metal and find that you can get steel nails to polarize easily. This might help people who want to do magnet experiments but reduce the magnet count. The fields don't seem to become easily stressed in this configuration. I know a couple magnet motor groups out there who may find this useful.  ;)
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MarkE

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Re: Are partial monopoles possible?
« Reply #4 on: September 20, 2014, 10:57:50 AM »
The nails are acting as pole shoes to the permanent magnets.  If you remove the permanent magnet and place one of the nails close to a compass, then you will find that the nail has two poles.
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Newton II

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Re: Are partial monopoles possible?
« Reply #5 on: September 20, 2014, 11:47:03 AM »
The word 'monopole' itself is meaningless.  It is only the direction of flux or direction of lines of force which determines the polarity.

When you consider magnetic flux as a 'line of force',  a line should have two ends.  One end is north pole and the other end is south pole. So, north and south poles will be present at all points in a magnetic field.  But the direction at north pole will be S-N projecting away from the pole and direction at south pole will be N-S projecting towards the the pole.

'Monopole' means a line with just one end and a line with just one end doesnot have existance.
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DreamThinkBuild

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Re: Are partial monopoles possible?
« Reply #6 on: September 20, 2014, 04:09:56 PM »
Hi MarkE,

I agree with that, when you remove the magnet the two poles return on the nail. When the magnet is fixed over the nail though the entire nail reads north, the other pole is redirected.

Hi NewtonII,

Thanks for the clarification. I guess it's more redirecting the lines of force than monopole.

I know this may seem pretty simple to some but there is something interesting when you start to use thinner material like transformer laminates. When passing a magnet over the edge of a laminate with about 1mm-2mm spacing the laminate becomes N polarized. Multiple laminates can be wedged to focus the redirected pole at one end while a weaker field resides at the fanned end. This difference in magnetic field could be used.
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gyulasun

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Re: Are partial monopoles possible?
« Reply #7 on: September 20, 2014, 05:44:29 PM »
Hi DreamThinkBuild,

Your photo labeled as FD.jpg shows an interesting motor idea if I am not mistaken? Suppose you populate the rotor (shown on the right hand side of the photo) with pole-wise properly positioned magnets, there would remain two sticky points? I assume these points would come about at every half turn of the rotor?
Why you name it 'magnet degausser'  I wonder.   :)

Thanks for showing these ideas.

Gyula
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DreamThinkBuild

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Re: Are partial monopoles possible?
« Reply #8 on: October 13, 2014, 07:09:48 PM »
Hi Gyulasun,

Sorry for delay in reply. I'm still working on different designs. I called the other one the fancy magnet degausser :) because it has the same field pattern as the straight track which has become noticeably weakened over time. This is more of a test bed than functional.

Attached is the picture of the nail version, the brown stuff is just modeling clay, I made a miscalculation error so it doesn't friction hold so clay is used to keep the nails from moving.

I have some .5mm iron sheet which I will be using to make a new one to eliminate the large spacing between the nails. I'm seeing an interesting effect (pull in one direction) when not using repulsion but attraction, but the nails spacing is to large so it has discontinuity between breaks so it gates. It is like stair step effect. I'm doing more measurements so I have values to build a new model.
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