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# Re: [femm] about magnetization of magnets

- To: femm@yahoogroups.com
- Subject: Re: [femm] about magnetization of magnets
- From: Dave Squires <djsquires@plix.com>
- Date: Mon, 22 Sep 2003 10:22:44 -0700
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    I have found the same thing, but there is not much you
    can do about it. FEMM assumes that the magnetization
    direction and/or angle specified applies to the entire
    block. Therefore, if you want a changing angle of magnetization
    you have to break the magnet up into sections with incremental
    angle changes to mimic a changing angle of magnetization.
    I have made up toroidal magnets with a circular magnetization
    this way. The easiest way is to make up the geometry and
    put in one property. Then you copy it radially and the
    angle will change automatically. If you need alternating
    polarities then copy two magnets radially at twice the
    angle of one alone. It's actually very easy to do once
    you know how.

    Regards,
    Dave Squires

`Ramdane LATEB wrote:`

> `hello femm's members,`
> `My question is about magnetization of magnets, it seems
> that the magnetization in femm depends on the number of subdivisions in magnets, I mean even if I put a radial magnetization in the middle of a span magnet, this seems true if the span is very small, but if the span is important I have to split the magnet into sub-magnets. What (I think)
> I have understood is that it's rather a global magnetization,
> more largest the span is, more parallel the magnetization
> is, and less largest the span is, more radial the magnetization
> is, so to have a radial magnetization I have to split the magnet into sub-magnets. I 'm wondering if someone else have observed this phenomenon in femm (perhaps it has been discussed before, if so , thank you to direct me to the corresponding messages). or your own experience, trie with a span magnet of 150° (electrical), with out splitting the magnet, and look to the back fem (or magnetic flux) in one tooth and the cogging torque (no load), and make the same when splitting the magnet in four (I mean splitting ,by just adding radial segments and adding a radial magnetization in each created sub magnet, and use a same mesh to approach the number of global nodes), the difference is rather observed in both cogging an tooth magnetic flux.`
> `Any advice is welcome, thank you`
> ``
> ``
> `
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``
``

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    - From: Ramdane LATEB <ramdane.lateb@ensem.inpl-nancy.fr>

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