Re: NST cap matching

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Peter.Lawrence-at-Eng.Sun-dot-com>

Terry,
      I did some experimenting last weekend, I had available a variety of
Cap sizes for a newly aquired (used) 9-30 NST which I calculate as using
a Res-Cap of 8.8nF, same as you. 

I am using a static gap (and I'm finally using a good brass ball safety gap, 
after ruining a 7.5-30 NST by running without a safety gap, guess I'm on the 
"standard" learning curve!!!)

I tried (with static gap)

	4.8nF	(Res/2)		"zzzzzzz" fuzzy hissing sparks
	9.6nF	(Res)		ok
	14.4nF	(1.5*Res)	best compromise, for my taste
	19.2nF	(2*Res)		"BBBBBBBB" sharp BANGing sparks

it might be good for everyone to try these for themselves as there are great 
subjective differences in the sparks each gave. I have a personal preference 
for the type of sparks that the 14.4nF Cap gave me, and I will probably 
stick with that, others will have their own preferences.

14.4nF is pretty close to what you call "Static LTR". Did you choose that 
based on subjective looks, or other reasons.  As long as a safety gap is 
used, is there any reason for folks not to try this range of Cap sizes.


On another note, the claim that 25" sparks should be possible with a 9-30 NST,
does that apply to a static gap, I'm only getting about 12+" streamers. I'm
not unhappy with that, I've finally got streamers as long as my coil is high,
which has always been my goal, but I'm wondering if I can do it with less
power (and still use a static gap).


-Pete Lawrence.



	Hi All,

	I made this little chart that shows what caps go with what NSTs

	Transformer	Resonant(BPS)	Static LTR	Sync Rotary LTR 
	15/60 		10.61nF (194)	15nF 		28nF 
	15/30 		5.305nF (201)	10nF 		14nF 
	12/30 		6.631nF (200)	9nF		17nF 
	9/30 		8.842nF (200)	12nF 		24nF 

	The LTR coils run at 120BPS and the resonant coils run at ~200BPS.

	Cheers,

		Terry