Magnet confusion
Magnet confusion
(OP)
Hi everybody,
I'll not lie: I joined this forum to see if I could find somebody so kind to help me with a simple question.
In the first picture I have represented the lines of force of a couple of magnets.
One is small, and represented in its entirety, the other one is much larger and only its North pole is represented.

So, question n. 1, are the line of force roughly right or not?
Based on the lines of force from the first picture, I have made another picture which shows what the vector power of the magnet should be.

The big N of the large magnet is pushing away the North of the small magnet while also pushing it in the South direction (right), while the South of the small magnet is being attracted to it vertically as well as being pulled to the right side.
The overall vector should result first of all in the rotation of the magnet along its axis, AND moving it to the South direction.
My question is: am I right or not?
Thank you in advance for your help!
Marco
I'll not lie: I joined this forum to see if I could find somebody so kind to help me with a simple question.
In the first picture I have represented the lines of force of a couple of magnets.
One is small, and represented in its entirety, the other one is much larger and only its North pole is represented.
So, question n. 1, are the line of force roughly right or not?
Based on the lines of force from the first picture, I have made another picture which shows what the vector power of the magnet should be.
The big N of the large magnet is pushing away the North of the small magnet while also pushing it in the South direction (right), while the South of the small magnet is being attracted to it vertically as well as being pulled to the right side.
The overall vector should result first of all in the rotation of the magnet along its axis, AND moving it to the South direction.
My question is: am I right or not?
Thank you in advance for your help!
Marco





RE: Magnet confusion
RE: Magnet confusion
RE: Magnet confusion
https://dl.dropbox.com/u/858716/various/magnets/IM...
https://dl.dropbox.com/u/858716/various/magnets/IM...
RE: Magnet confusion
RE: Magnet confusion
RE: Magnet confusion
http://www.supermagnete.it/eng/M-04?img=7
Btw it is not possible to edit posts in this forum?
RE: Magnet confusion
RE: Magnet confusion
Is my hypothesys correct?
RE: Magnet confusion
I just simplified it because of posting the stuff here, but if this becomes a main parameter I will explain better.
It's a long magnet, whereas the North face is pointing to the small magnet.
In reality, it's as thick as the small magnet (3 mm), only longer, and the North pole is facing the small magnet.
So, not so big, and the South is right under the North
I can add that the power for square millimeter is practically the same for both magnets, N35 or N42, something like that.
RE: Magnet confusion
b.t.w., N35 N42 are most likely the grades of NdFeB magnets, not square mm.
RE: Magnet confusion
RE: Magnet confusion
RyreInc can you tell me what's that software you used? Is it free or not?
I notice that the bottom magnet is not put in horizontal position, why? Is it possible to make it larger?
That's the essence of my question, as to also know if the small magnet would "travel" from North to South.
Thank you again, really grateful!
RE: Magnet confusion
RE: Magnet confusion
So I think the small magnet in this case will not travel anywhere, it will only rotate on its axis if I understand well.
The problem is, this is not the right configuration.
The bottom magnet must be large, much larger than the small one.
Thank you for the FEMM thing, I'm going to install it right now and I'll let you know
RE: Magnet confusion
TTFN
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RE: Magnet confusion
Move, rotate and scale are simply a hell!
Anyway, I managed to create some points and connect them with lines.
Now, how to tell which is North and which South?
I tried to use the properties menu but no way to assign anything to the points I selected.
I open the library and... can only watch the materials but not assign them?
RE: Magnet confusion
Assuming the bottom magnet is fixed, and the upper magnet is free, the upper magnet will move.
But it will not move in one direction or another, it will only rotate on its axis.
As you said, the final position will be contact South on North, not much of a science here.
But if you watch closely, the first point of contact are the two corners I mentioned.
This said, I understand that the problem I propose is not detailed enough to obtain the answer I need.
Let's see if I can make it a little bit more clear.
Imagine that the small magnet is free in movement on a horizonatl axis, and NOT free of rotating.
I suppose the magnet wouldn't move anywhere.
But still, I think that the simulation would be much different from this one if the bottom large magnet would be much larger than the upper one, like in my drawings.
RE: Magnet confusion
The way you have it drawn in the first picture, one could interpret it a few ways: The upper magnet could have a single arrow pointing right to left, indicating simple thru magnetization; or it could have an arrow pointing up on the left and an arrow pointing down on the right, indicating a two-pole (per face) configuration. These are very different! But using arrows instead of poles to begin with gets rid of this ambiguity. Plus, dividing the magnet into N and S regions implies that you could separate the two and be left with a pair of monopoles!
All of this is a roundabout way of saying that you can't specify North or South poles in FEMM, or any FEA software, only direction of magnetization. I've never actually used FEMM, so I don't have any specific help on manipulating the software.
RE: Magnet confusion
RE: Magnet confusion
Unless it's actually pivoted, no. There will be rotation, yes, but there will also be translation. It's most like that the free magnet will wind up overhanging the right edge of the fixed magnet. Every termination of a line of force will be subject to attraction, so, even the portion to the right of center will be attracted and will move toward the fixed magnet.
TTFN
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