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# Re: [femm] Permanent Magnet Data

- To: femm@yahoogroups.com
- Subject: Re: [femm] Permanent Magnet Data
- From: David Meeker <dmeeker@ieee.org>
- Date: Tue, 15 Apr 2003 15:03:02 -0400
- In-reply-to: <b7hfsg+m8og@eGroups.com>
- References: <b7hfsg+m8og@eGroups.com>
- User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3; MultiZilla v1.4.0.3G) Gecko/20030312

`tano1938 wrote:`

>     Are the BH curve data and the coercivity values for permanent magnet
>     materials given in the materials library intrinsic values or do they
>     include the free space permeability as well? I'm having some problem
>     relating this data to published data from the manufacturer. Also, is
>     the data for Alnico series for cast Alnico? I'm assuming that I can
>     shift this data by the coercivity value to obtain second quadrant
>     demagnetization curves.

> `Thanks for the help`

`The information in the femm B-H curve for a permanent magnet is the "normal" demagnetization curve (as opposed to the the "intrinsic" demagnetization curve, see http://www.magnetweb.com/Sect1C.htm for an explanation) shifted to the right by Hc. You can recover the second quadrant normal demagnetization curve by subtracting Hc from the H values listed in the tables.`
`The Alnico 8 curve was obtained by digitizing figure 4-2(a), "Unit property curves for anisotropic cast Alnico," from:
R. J. Parker and R. J. Studders, "Permanent magnets and their application," John Wiley and Sons, Inc., New York, 1962
The Alnico 5 and 6 curves were cribbed from the "Standard handbook for electrical engineers." Although it is not noted whether or not these are cast alnicos, the demagnetization curves don't differ drastically from the curves for Alnico 5 and 6 from the Parker and Studders book.`

    Dave.
    --
    David Meeker
    email: dmeeker@ieee.org
    www: http://femm.berlios.de/dmeeker

- References:
  - Permanent Magnet Data
    - From: "tano1938" <rgarritano@comcast.net>

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