Mike,

I think, if done properly that might work.  In=20
the gap between the magnet N poles you would get=20
an intense field coming out at right angles to=20
the magnets' axis, which would be the region=20
where you would put the coil.  The main problem=20
would be figuring out how to mount the magnets=20
and coil and possibly how to provide iron return=20
paths for the flux lines which would be spraying=20
out all around the ends of the magnets.

There is a magnet design program called=20
'femm'--finite element method magnetics.  It's=20
not all that easy to learn, but it would tell you=20
everything you ever wanted to know, and more,=20
about any cylindrical magnet/coil structure you designed.

For an example one of the many things it does,=20
take a look at the plot for one of the Inyo Force=20
Balance Vertical coil designs.
   http://www.bnordgren.org/seismo/FBV/InyoMagnet.jpg

Regards,
Brett

At 12:02 PM 8/11/2010, you wrote:
>Hi everyone,
>
>Here=92s a question I=92ve always wanted to=20
>ask:  Why (if the number of magnetic lines of=20
>force cut per unit time produces a current flow)=20
>is it not possible to force two identical=20
>magnets together so that they=92re oriented (for=20
>example) N pole to N pole.  It seems to me that=20
>the lines of force would crowd together so that=20
>the least movement of them would produce quite a strong response in a coil.
>
>I built a simple vertical seismometer with a 5=20
>pound plumber=92s lead as the weight, a spring and=20
>two cow magnets forced together in a 4 inch PVC=20
>tube so that the resting position in the coil=20
>was the point at which the maximum lines of=20
>force resided.  It made a lot of sense when I=20
>designed it but I didn=92t have a good environment=20
>in which to test it; e.g. A 500 foot TV station=20
>antenna within 50 feet; an expressway two blocks=20
>away and a location inside a TV studio.  To be=20
>sure, it was a short period sensor and it indicated a lot of local noise.
>
>I=92m not a seismologist (that should be quite=20
>evident) =85 I=92m a retired electrical engineer who=20
>specialized in grounding and lightning &=20
>transient damage risk mitigation.   I was just  curious and thought I=92d=
 ask.
>
>Miguel Lozano
>Lockhart, TX
>
>


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