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Date: Wed, 21 Sep 2011 18:08:06 -0700
From: Andrew Poelstra <asp11 AT sfu DOT ca>
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Subject: Re: [geda-user] gEDA-user: Electromagnetic bike
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On Wed, Sep 21, 2011 at 11:45:17AM -0400, Rob Butts wrote:
> 
> I'd like to order material to start prototyping.  I would like to be able to
> calculate approximate torques for given size disks of aluminum or copper and
> approximate size, quantity and strength of magnets mounted to a disk a given
> proximity away.  Does anyone know the theorey and how I would try to model
> this to calculate the variables and purchase materials to begin a
> prototype?  Or refer me to a source covering the theory?
>

This is touched on in first- and second-year physics, so any elementary
text on electromagnetism should talk about it. However, there is not a
lot of quantitative information known about this, since the paths of the
specific eddy currents aren't very predictable.

I had a homework assignment about this last year that made some (very)
questionable assumptions to get an idea of the torque involved, which
you might find instructive nonetheless.

I have my answer, but can't find the original question, unfortunately..I'll
have to ask the prof.

-- 
Andrew Poelstra
Email: asp11 at sfu.ca OR apoelstra at wpsoftware.net
Web:   http://www.wpsoftware.net/andrew