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Re: toroid sizing





On Wed, 29 Mar 2000 21:34:25 -0700 Tesla List <tesla-at-pupman-dot-com> writes:
> Original Poster: Fucian-at-aol-dot-com 
> 
> Hi all,my coil is 3ich by 15inch 

Is that 3" measured, or are you using 3" PVC? That 3" is the inner
diameter of the pipe, unless you are using CPVC. The usually schedule 40
stuff has walls about 1/4" thick.

wound with 24awg.the frequency is 
> like 
> 475khz.

If it is really 3.5", then with the topload it will resonate at about 354
kHz, and 670kHz without
if it is 3", then about 414kHz with the topload, and 800kHz without. (all
according to Wintesla)

im using a 9kv30ma the primary is 11 turns of copper 
> tubing.

please provide more detailed information about the primary type. Is is a
flat spiral, conical, or a vertical helix? What is is the spacing between
turns?

(assuming the secondary is really 3" dia)If you use, say, a 6" dia
vertical helix, with 3/8" spacing between turns of 1/4" copper tubing,
then 10 turns exactly will work with a impedance matched capacitor for
your NST, .009µF. If you remove the terminal, then it should tune it at
about 4.5 turns, assuming the capacistance is still .009µF.

my current 
> toroid is 4inch diam.by about 15 inches long still in compressed 
> form.i cant 
> get any streamers!i evenswitched over to a 15kv30ma and 
> retuned.still no 
> diff.how do i get streamers?

Can you describe the capacitor you are currently using? Mistuning seems
the most likely culprit right now.

should i try and return it and get 2 
> small mixing 
> bowls for the coil,or should i cut the ducting to a smaller 
> lenght?
No, leave the ducting as it is, but do try and find a pair of small steel
mixing bowls. Also try and tune it with out any terminal whatsoever.

key word 
> here is cutting,once cut,no refund! i have very little time left to 
> work on 
> it.what am i to do?

Radical tuning methods. If you're using SW caps, then try anywhere from 3
to 10 of them, and vary the number of primary turns all over the scale.
Also check that there are no shorted turns on the secondary, or shorted
turns on the primary. These will both keep it from operating. 

Good luck to you, email me (or pretty much anyone on the list, I suspect)
and I'll be glad to offer specific advice

Grayson Dietrich
http://www.electrophile.8m-dot-com


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