Re: spun toroids

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 6/4/01 2:59:46 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

>  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.

Bart,

That is all well known.  My suggestion for the fat toroid is a sort of
compromise to keep the toroid a little smaller, and yet get very
powerful sparks.  Since such a toroid will have less capacitance,
it will be able to break out of a larger ROC than a wider diameter
toroid.  This is the approach that Malcolm used on his coil.  He
has a 9" by 25" (approx) pseudo-toroid on a 10" dia secondary.
Not much work has been done which such aspect ratios to see
how they perform in the real world.  It certainly would be interesting
to do more experiments.  Such a fat toroid would also fit in well
with the idea of using smaller diameter secondaries than normally
used.  The loss of L would be compensated for by using a little
thinner secondary wire gauge.

Cheers,
John

>  
>  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