On Jan 12, 2010, at 6:49 PM, Stephen A. Lawrence wrote:
On 01/12/2010 06:29 PM, Terry Blanton wrote:
On Tue, Jan 12, 2010 at 4:05 PM, Stephen A. Lawrence
<sa...@pobox.com> wrote:
[And by the way I'd still love to see a sketch of the field of the
toroidal magnetic cores, if anyone happens to have a link to one
(don't
spend a lot of your time searching the Steorn site for a diagram,
tho,
please, just to save me the time to do that, wouldn't be fair).]
This is from one of Fred Sparber's (GRHS) favorite sites (mine, too
since it's from Ga):
http://hyperphysics.phy-astr.gsu.edu/Hbase/magnetic/toroid.html
Thanks, Terry... but unfortunately, that page is not what I'm looking
for. That's the field of the coil, and it's entirely contained within
the toroid.
I'm looking for a sketch of the field of the toroidal *core* when the
current is switched off. For the magnetism of the core to mean
anything, that field must not be entirely contained in the toroid, and
consequently must not be a purely circular field running parallel
to the
torus ring.
The field of a permanent magnet must be either anchored in the
magnet's
material, or knotted around part of the magnet, as in the attached
sketches. But those aren't the only possibilities for a toroidal
magnet, and I don't know what the fields of the Steorn toroidal
magnets
look like.
("bad" in the image file names refers to the quality of the sketches,
which are, well, bad...)
<bad-toroidal-field-2.jpg><bad-toroidal-mag-field-1.jpg>
I can say that, experimentally speaking, it was surprising to me the
degree to which the field of a toroidal coil is entirely contained
within the torus surface, even if that surface is highly distorted.
Here is an experiment I did along those lines:
http://www.mtaonline.net/~hheffner/OddTransNotes.pdf
I tried to make a transformer that could tap the fringe field energy
of a highly distorted toroid surface. There was very very little
there to tap!
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
