Re: Secondary design help

• To: tesla-at-pupman-dot-com
• Subject: Re: Secondary design help
• From: "Megavolt Nick" <tesla-at-fieldfamily.prontoserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Tue, 22 Feb 2000 18:34:33 -0700
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Mark,
              my comments:
> Original Poster: "Mark Broker" <broker-at-uwplatt.edu>
>
> I'm building my first "big" coil, and would like to make it as good as
> possible without making too many mistakes.
nice aim :-)
>
> So far, my design consists of a 1.8kVA input (dual 15/60 NSTs) with an
> LTR-style MMC (56nF).  My primary is .50" copper tube spaced .50."  I'm
I see your going for the twice resonant approach, which should work well
with your srsg.

> working on a SRSG at 120 BPS.  I'd like to use a 6.27" OD, 6.07" ID x ~30"
> PVC secondary with 22AWG wire.
>
> The only areas that I'm still trying to investigate are the secondary
> design and the topload.  First, I've read that PVC doesn't make a very
good
> form due to its high RF losses.
You have to get some perspective on the losses - the pvc is more lossy, but
even the 'more lossy' pvc doesn't significantly reduce your spark length.

30", allowing for 1" inset on each end, gives you 28" winding length which
is an aspect ratio of 4:5, apparantly the optimum.

> Secondly, I'm concerned that 22 AWG is too
> small, and that I should use 20 or 18 AWG.  Finally, I'm also concerned
> that the topload is too small ("Top loads can NEVER be too big").  I've
> thrown a 6"x 24" toroid into WinTesla, with a capacitance of 32pF.  I've
> seen on one Web page that the recommended toroid size for a 6" coil is
> 8"x40" (60pF) (in conjunction with an anit-corona ring, which I may add
> after I get it built and working well).
What's the problem, the topload is not the biggest you could run - so put a
bigger one on latter.

>
> So, my questions are:
>     1:  Will I gain much by using a PE (or similar) form over a PVC form?
Not much

>     2:  Is 22AWG wire OK on a 6" coil running at 1.8kVA?
I'd go for something larger, maybe 20 guage

>     3:  Is my topload of 6x24" too small for my coil?  (I DO intent to
make
> a couple, but I'd like an idea of where to shoot for)
It's a good place to start - toroids are easy to make (they don't even have
to be toroids, if you think it'll help stick the wok on top of it) so just
add them as you go along.

Regards
Nick Field

>
> Thanks.
>
> Mark
>
>
>

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