On 2011-02-04, Winston wrote:
DoN. Nichols wrote:
On 2011-02-04, wrote:

[ ... ]

Aligned side-by-side, wouldn't these magnets repel
each other?

Yes -- but if properly clamped down, that would not do anything
bad.

We both think that there would be significant weakening of the
clamping action, at least in the 'like poles' area, yes?

Yes. (At least I know that *I* believe it.

[ ... ASCII graphics snipped -- quoting levels distort it ... ]

2 becomes 3 and follows 1, then becomes 4 for the trip back, etc. Since
the end poles of a typical core are half the width of the center core
this would make equal area poles except at the very end, and alternating
poles fairly close together for maximum grip. How many turns would be
needed would be fun to calculate, of course. :-)

Not as much fun as designing that coil winding machine!

I'm getting a headache trying to think of a way to make that
inductor more than one layer deep.

Take a piece of rope the right diameter to fit between the
poles. Thread it in the figure-8 shape though the poles. Cut to length
where the ends overlap. Take it out, and make a wooden form which is
perhaps just large enough to leave a 1/2" gap between the ends. Cut
grooves in the form about every inch.

Wind enough turns on the form to duplicate the diameter of the
rope.

Thread lacing tape through the grooves and tighten lace loosely.

Lift free from the form (perhaps bolt-on flanges to keep it
clustered until time to remove).

Push the bundle of wire to the bottom of a slot near one end,
and work your way down to the end and back and around the final end.

Add more lacing tape to tighten the bundle, and then treat with
the lacquer used for motor windings to keep the wires in place in the
row of poles.

I've done something like this years ago, when rewinding a burnt
out three-speed inverted rotor cap run capstan motor for a tape deck.
Except that I did not have the proper lacquer to finish the job. There
were patterns passing through every other slot (with the secondary
winding passing between the slots already used, then more windings going
through every fourth slot, with the second one going through the ones
mind-way between, and finally windings going through every eighth slot,
and through those half-way between those. *Lots* of magnet wire used in
that project. :-)

(...)
The center of each pole -- or combined pole -- would have less
flux than the edges, so smaller poles are better -- up to the point
where the flux loops back before it significantly penetrates the
workpiece to reach the clamp bar.

Termed 'leakage flux', yes?

That sounds like a good term.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---