Re: spun toroids

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi John,

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<FutureT-at-aol-dot-com>
>
> Bart, all,
>
> I like the idea of a light-weight large toroid too.  The Langegran
> toroid was 0.125" thick I think.  Somehow I suspect that if one
> of them was dropped on the ground, it would get dented, even
> using 6061, but I may be wrong about that.  It seems to me the
> greater weight of a thick toroid would cause it to fall with more
> momentum, making denting likely anyway although I'm not sure
> if it works quite that way.

Sure, the greater the weight, the greater the impact. The thinner the wall, the
greater the impact. It's a tradeoff. I think we just should keep them thin,
 not
"drop" the toroids, and simply have them packed well for shipment.

> Speaking about toroid dimensions, I wouldn't
> be surprised if it's a good idea to make the minor diameter large
> relative to the major diameter.  For instance a 10" by 30" toroid
> may be preferable to a 8" by 30" toroid.  A 12" by 30" toroid may
> be even better.  Such a "fat" toroid would hold off large voltages,
> to handle a lot of power, yet, the toroid would not fill the Tesla
> lab as much.  I don't think very many experiments have been
> done to analyze the relative benefits of a fat toroid vs. a thinner
> aspect ratio.

Ah yes. The fat toroid is appealing. But I'm not so sure that fat toroids are
necessarily the best way to go. For field control, I can see a fat toroid is
useful. Breakout tends to occur slightly above (or below) the outermost
edge and
this is helpful with a fat toroid. But to gain the most top capacitance for the
toroid size, my recent testing has shown that if the toroid proximity is
further
away from the secondary (a large outer diameter), the effective top capacitance
increases closer to it's free-space value. Because of top C, the cord
diameter is
then smaller to maintain the same capacitance.

John, these past 4 years on the list, I've kept my eye on some coilers who have
rather large diameter toroids with rather small diameter cord sizes. These
coils
did very well. Field control is not altered because of the increased breakout
proximity from the secondary.

My personal toroid wantings are a 10" x 40" toroid. This keeps ROC
excellent for
higher powered sparks and keeps the proximity to secondary large (4:1 aspect
ratio). But for some of the people wanting to take part of this bulk buy,
have to
wonder if they have enough power to breakout on a toroid of this size (I
know David
and I can, but not sure for others). I'll be happy to go with whatever the
consensus is.

Take care,
Bart Anderson