[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# Re: [femm] Magnetization circumferencely

- To: femm@egroups.com
- Subject: Re: [femm] Magnetization circumferencely
- From: David Meeker <dmeeker@foster-miller.com>
- Date: Fri, 08 Sep 2000 09:40:11 -0400
- Organization: Foster-Miller, Inc.
- References: <8p8jq2+m57s@eGroups.com>

    wilsons@avonil.net wrote:

    > Hi I am a new user of femm and am trying to get a circular donut
    > magnatized cicumferencely and am having a hard time figuring out how
    > to do this. I am a senior level college physics student and have
    > tried everything that I could figure out. Any help in this would be
    > greatly appreciated. Thanks in advance.
    > Jason

    There are a couple of ways that you could do this. A physical configuration
    that actually acts this way is a toroidal core wrapped with wire. A 2-D
    planar simulation would be modeling an axial cross-section of the toroid.
    To make the field, you then have to model the coils that would be wound on
    the toroid. This would consist of a circular region in the bore of the
    toroid defined with a current density. You could then put a second coil
    region external to the toroid, also with a current density defined--this
    current density should be the negative of the value defined in the bore.
    Then, specify A=0 on the outer boundary of the outer coil. This results in
    a purely circumferential field in the iron. See cylinder2b.fem in the
    attached zip.

    A different "quick and dirty" way to make a circumferential field is to
    assign the inner bore of the toroid to be A=0 and assign the outer boundary
    of the toroid to be some nonzero value of A. Specifically, if you want an
    average flux density to be B in the toroid (that is, the average of B along
    any radial line linking the inner and outer boundaries of the toroid),
    define the outer boundary to be A=B(ro-ri), where ro is the outer radius of
    the toroid, and ri is the inner radius. See cylinder2a.fem in the attached
    zip.

    Dave.

    begin:vcard
    n:Meeker;David
    tel;fax:781-890-3489
    tel;work:781-684-4070
    x-mozilla-html:TRUE
    url:http://members.aol.com/dcm3c
    org:Foster-Miller, Inc.;Electrical and Electronic Systems Group
    version:2.1
    email;internet:dmeeker@foster-miller.com
    title:Senior Engineer
    adr;quoted-printable:;;350 Second Avenue=0D=0A;Waltham;MA;02451-1196;USA
    fn:David Meeker, Ph.D.
    end:vcard

- References:
  - Magnetization circumferencely
    - From: wilsons@avonil.net

- Prev by Date: any body know?
- Next by Date: Re: [femm] Magnetization circumferencely
- Previous by thread: Re: [femm] Magnetization circumferencely
- Next by thread: Re: [femm] Magnetization circumferencely
- Index(es):
  - Date
  - Thread