Magnetic force through a structure?

Discussion in 'Physics' started by shortbus, Mar 7, 2012.

  1. shortbus

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    Sep 30, 2009
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    What is the proper term for a magnetic field/force through a ferrous/iron structure? I've beat my head against the wall trying to find the correct term in Google.

    What I am after is how magnetic field from a permanent magnet is guided through a ferrous part in a machine. Such as in a small toy DC motor, the cheap style that has one magnet and two iron "fields" that the rotor turns in. Or like in a magnetic cabinet latch, the kind that has a magnet between two iron pieces, that hold a door closed.

    Can anyone help with some suggestions on where to find more information?
     
  2. praondevou

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    Maybe "magnetic flux density distribution inside ferromagnetic material"?

    I typed it and chose images (in google).

    For exact information you will need a magnetic field simulation software. We have one in our company but I can't remember the name right now. (I'm not familiar with it) Takes several days to calculate complex fields, e.g. of a DC motor.
     
  3. THE_RB

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    Magnetic flux?

    (edit) Haha! Darn I must have beat your post by seconds but it would not accept my reply of "Flux?" as it was less than 10 characters... So I had to edit to add "Magnetc" and re-submit which cost precious seconds. ;)
     
  4. amilton542

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    A current carrying conductor will experience a force when placed in the vicinity of a magnetic field, which can be referred to as the 'BIL' force. I suppose the core could suffer damage from mechanical force in some way shape or form due to a short circuit inside a transformer, where the axial and radial components will be to blame.

    The magnetic flux will follow the path of least reluctance and become denser because of the permeability of the core. There is less 'effort' to travel through a material with a high permeability, why would it stay in the air? Except for leakage flux.
     
  5. studiot

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    I'm afraid your question is a bit vague.

    There are several quantities describing different aspects of magnetic field behaviour rather than a single one.

    Magnetic flux, magnetic flux density, magnetomotive force, magnetic field strength are all candidates to answer your querstion.

    This is a good link to review.

    http://info.ee.surrey.ac.uk/Workshop/advice/coils/terms.html
     
  6. shortbus

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    Thanks guys for the answers. This is the only type answer I've found on this, too. Don't know really how to describe what I want to know.:(

    How is a magnetic flux transmitted through the material? Not the true physics of magnetics but the practical part of it. And not by an electro magnet but a permanent magnet. All I come up with has to do with transformers or biological research.
     
  7. praondevou

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    You want to know why when attaching a permanent magnet to a ferromagnetic piece of metal the latter becomes magnetized,i.e. can itself attract other ferromagnetic materials?

    Maybe it's the reorientation of magnetic domains you are looking for?
     
  8. amilton542

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    shortbus likes this.
  9. shortbus

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    Thanks Prandevou, but that doesn't link to it either. I'll draw up a sketch and post it to try and explain better.
     
  10. studiot

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    Good idea.
     
  11. praondevou

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    I found this in one of my documents. Don't bother the french text. It shows the concentration of magnetic flux inside ferromagnetic material of various shapes. The sourrounding matter is air. The originating magnetic field in this case is the earth's field (uniform).

    It shows what Amilton542 said in his post.
     
  12. shortbus

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    Thanks every one, I'm going to buy a couple of neodymium magnets and just experiment. What I'm working on is a rotor for a IPMSM (interior permanent magnet synchronous motor)
     
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