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

# Re: Voice Coil Motor with Aluminum bobbin

- To: femm@yahoogroups.com
- Subject: Re: Voice Coil Motor with Aluminum bobbin
- From: "tano1938" <rgarritano@comcast.net>
- Date: Tue, 27 May 2003 14:16:55 -0000
- In-reply-to: <3ED2876F.2090402@ieee.org>
- User-agent: eGroups-EW/0.82

    --- In femm@yahoogroups.com, David Meeker <dmeeker@i...> wrote:
    >I'd guess that the node at (0.01,-0.325) should really be at (0,-
    0.325), but other than than, the solution looks like I'd expect.
    You'll also need to specify a nonzero conductivity for the 1018 steel
    to get the eddy currents induced in those parts.

    The result is just the AC part of the field due to the coil. Remember
    that the program isn't solving the combined AC + DC offset problem--
    it can only solve one part at a time. Additionally, the AC problem
    considers only major hysteresis loops (i.e. no DC offset). I
    occasionally threaten to write a combined AC + DC offset program,
    because this scenario keeps popping up in the context of a lot of
    practical problems, but I haven't gotten around to it yet.

    Anyhow, since your DC problem has significant nonlinearity, you'll
    have to be careful how you set up the AC problem--you can't just
    superimpose the results in the way that one can for linear problems.
    For AC analyses, you'd want to replace the alnico with a linear
    material where the permeability of the magnet is chosen to be
    representative of the incremental permeability at the nominal
    operating point. You may have to do a similar trick with the 1018 in
    the areas with high fields in the DC problem.

    Dave.

    Thanks Dave. I should have read the manual closer.

    Would it be OK to model the Alnico magnet with a linear material like
    you suggest, and use the published "recoil permeability" of Alnico 5,
    which is about 5.0?

    Ron

- Follow-Ups:
  - Re: [femm] Re: Voice Coil Motor with Aluminum bobbin
    - From: David Meeker <dmeeker@ieee.org>

- References:
  - Re: [femm] Voice Coil Motor with Aluminum bobbin
    - From: David Meeker <dmeeker@ieee.org>

- Prev by Date: egun simulation
- Next by Date: Re: [femm] Re: Voice Coil Motor with Aluminum bobbin
- Previous by thread: egun simulation
- Next by thread: Re: [femm] Re: Voice Coil Motor with Aluminum bobbin
- Index(es):
  - Date
  - Thread