RE: Odd/errratic TC behavior. Why?

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Gary.Lau-at-compaq-dot-com>

Hi Jonathan:

A .025uF cap may not be too large for a 15/60 NST.  My 15/60 uses a
.02uF cap and does just fine with my static gap, and Terry's 15/60
system uses a .027uF cap with a sync RSG.  I would be more concerned
with the small number of primary turns you have, as this will increase
gap losses.  Also, such a small primary will have a very low coupling
factor, and that will also translate into poor output.

I'm not sure what you mean by "yellow sparks off the top of the tank
cap".  Your tank cap shouldn't have any sparks on it.

What's an "RRI" cap?  Are you sure that your cap is OK?  Your power
supplies seem more than ample to jump the gap.

Also didn't understand how the larger NST needs a smaller safety gap
setting.  True, the lower 12kV should have a somewhat smaller safety gap
setting, but it shouldn't be firing at all.

Good luck,
Gary Lau
MA, USA


>Original poster: "jpeakall by way of Terry Fritz <twftesla-at-uswest-dot-net>"
><jpeakall-at-mcn-dot-org>

>Howdy All,

>I made a vacuum gap like I saw on Gary Lau and Greg's (hotstreamer)
site.
>Wow! Easy to make (less than 3 hr.) and works great. Much better
output!
>Only trouble is, I was having so much fun, I blew a tank cap.
>
>Enter my problem. I have a .025 (actually tests to .023) RRI cap. In
spite
>of the fact it is too big for my 15kv/60ma, I hooked it up, and trying
all
>primary tap points and gap settings. I got a little, with it tuned to
1-2
>primary turns, but that was it. I wasn't really surprised, as that
tranny
>shouldn't really run it anyway, but it didn't act like a too big tank
cap
>has for me in the past (erratic SG behavior). It was firing fine over a
>range of SG adjustments, just no secondary output. When I tune the
primary
>really low, I get some yellow sparks off the top of the tank cap.
>
>So I pulled out my 12kv/120ma that I have for my new system I am
building. >I
>was a little concerned, as my coil is small, and I thought I'd have to
run
>at low power, as the .025 is close to a res cap for this tranny.
Anyway, to
>make a long story short, same deal. I tried gaps from .25 to .05. Nada.
>What
>gives? It fires the gap great. One thing I did notice is that
the12kv/120ma
>needed a SMALLER setting on the safety gap. Is this sucker just weak?
It
>does seem to have more ooomph once it jumps the gap, but won't jump as
far.
>In spite of the lesser voltage, I expected it to jump further than the
>15kv/60.
>
>I'm gonna go take a look at info to hook my two NSTs together tonight
and
>try it out. I have friends visiting this weekend that wanna see my
coil!
>Must..get....coil.....working.
>
>Thanks All,
>
>Jonathan Peakall