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Coil design

     
Yeah, I don't know what happened with that message.  i sent it to tesla-at-pupman 
like all the others.

I hope to move up to a bigger cap, probably MMC, and 120mA ganged NSTs at some 
point, but this is my first coil and i'm starting, well, medium:)

I finished the primary this weekend, and built the toroid last night.  It's 6" 
heating duct around 9" pieplates, so if I understand the toroid sizing 
convention correctly this toroid is 6" x 15" for around 23pF?  if it isn't big 
enough i'll build another.

As far as an NST protection network, I'm taking Adam and Terry and Gary Lau's 
advice and going to use a safety gap, a 1.8k 113w resistor on each leg and a 
500pf 30KV doorknob cap from each leg to ground.  I'm also going to use a
20 amp
line filter. I ordered these components from C & H Sales and i'm waiting to
get 
them.

I don't know yet what kind of performance i'm going to get because I haven't 
tried it yet!  Since all that's left is various mounting chores and wiring it 
up, I have high hopes for first light this weekend or next. . . . Gotta go buy 
some welding cable. . .  .

paul

______________________________ Reply Separator
_________________________________
Subject: Re: Paul's design (no subject originally)
Author:  Tesla List <tesla-at-pupman-dot-com> at InterNet
Date:    2/23/00 7:16 AM


Original Poster: "Barton B. Anderson" <tesla123-at-pacbell-dot-net> 
     
> Original Poster: "Adam" <adamsmith-at-mediaone-dot-net> 
>
     
Hi Paul, I got this too. Comments intersperced.
     
> Post sent to wrong address? I got it from tesla-request-at-pupman-dot-com? 
> Anyhow...
>
> > Could you folks review my proposed NST protection circuit schematic? 
> >
> > 10 amp 0-140v variac
> > 12KV, 60mA NST,
> > Tank cap: .01uF Fair Radio cap
> > Primary: 16 turns .25" Cu tubing 
> > Secondary: 6"x24" 22 awg
> > Toroid: 6"x18" (approx) heating duct 
>
> Sounds good and solid.  Additional NST and 0.01uF (or so) will increase 
> performance in the future, without significant need to modify any other
> system components-- good flexible design Paul!  If your primary is a flat
> spiral, my design tool says it will tune with the tap between 12.5 to 13 of 
> the 16 turns. Good margin for corrections.
>
     
I agree with Adam here on both accounts. My calcs said 12.5 turns and I too 
would go up in capacitance 0.01uF. I would add also that I would like to see 
another 10pF (6" x 28" toroid) on top for about ~30pF total. Dare I say you 
might be able to push 50" streamers out then? (I might be a few picofarads 
over-
best to experiment).
     
What are you getting now Paul? 35"?  45"? Kind of curious.
     
Sorry, can't help witht the protection circuit - I haven't used one (like it). 
Adam's response sounded pretty good to me.
     
Bart