Re: [TCML] Toroid

[Scott Bogard <sdbogard@xxxxxxxxx>]

Hi Christian,
     John pretty much answered your question, but so you have a ballpark to
shoot for...  On a typical toriod you get ROUGHLY 1 pF per inch of overall
diameter (or such has been my experience.)  And the rule of thumb for
sizing a top load is a range, take your power (1.1kW) and get the square
root (33point something) now take this value and multiply by a constant of
0.5 through 0.9 (0.5 for many smaller arcs, 0.9 for one single arc) and the
resultant figure just happens to be the size in picofarads of your ideal
top load (so 0.5 gives us 16.5, and 0.9 gives us 29.7)  I think John Freu
was the one who discoved this, and it has always proven correct for me as
well...  But at any rate, for a single arc I would shoot for a 29.7 pF top
load, which will be roughly 29.7 inches in diameter...  Why this works I
could not say, I think it is a simple product of our mathmatical system,
and just happens to work, it is not a "proper formula" where all the units
come out even in the end, but it DOES seem to work...  So I hope that sheds
some light and proves helpful!

Scott Bogard
On Tue, Sep 25, 2012 at 12:27 AM, <jhowson4@xxxxxxxxxxx> wrote:

> Christian,
> Its not that you screwed up, your coil works just fine, just under
> different parameters.
> But you are correct increasing the size of the toroid, will generally
> produce more power arcs for a given input power. Just be careful not to go
> too big, i built one once that would not produce any arcs unless it had a
> breakout point. it did radiate a massive E feild though, I could like a
> florescent tube across the room.
> Increasing the smoothness of the toroid will also help you out, I find
> that coating the ducting in Spackle and then carefully sanding it down
> before applying the tape to be highly beneficial as it reduces corona
> points.
>
>
>
> Thanks,
> John "Jay" Howson IV
>
>
> "Why thank you, I will be happy to take those electrons off your hands."
>
> ----- Original Message -----
> From: "Christian Hill" <monolegal@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Monday, September 24, 2012 11:48:54 PM
> Subject: [TCML] Toroid
>
> Hello. I completed and ran my first Tesla coil this weekend. Putting it
> together and having it work was a very satisfying experience. I am
> not extraordinarily happy with the results, however. It is powered by three
> 12kV NST's in parallel for 1.1kw of power. The coil form diameter is 4.5"
> and the winding height is 22.5". It is currently throwing several(4-7)
> small to medium size arcs. (8"-24"). A breakout point helps, but I still
> think it's under performing.
>
> My question is, how can I get a single larger arc? I've seen several 1kw
> coils outperform my 1.1kw coil. I spent much time on and carefully planned
> almost (read on) every piece of this coil. I have a simple adjustable
> static spark gap. I have a very close to LTR capacitor array (off by about
> 1.1nf) and the coil is as tuned as it is going to get. The RF ground is
> good as well, I pounded an 8' grounding rod into the earth.
>
> The topload is where I think I screwed up. Not only is it rather small for
> my coil (4" ring, 16" total), it is rather poorly made. By poorly made I
> mean there are many ridges in the foil tape that is wrapped around the
> dryer duct. To get a single larger spark should I construct a larger
> topload? Or should I attempt to smooth out the edges in the foil tape? What
> size toroid would you recommend? I am considering a 4" ring x 20-22" total.
> Thank you for your help.
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla