Re: Terry, post this for me

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>



> 
> Anyway, I wasn't exactly shocked (pun intended) by its performance. I'm
> using a 12/30 NST (tho will be using a 15/30 later, and have plenty of NSTs
> to add). I can draw about 7" - 9" sparks, and I get no breakout from my
> toroid which is 4" x 22". I SHOULD be able to get at least 36" out of this,
> right?

The rule of thumb is 1.7*sqrt(VA) for the OPTIMUM configuration.  for a
12/30 (360W) you're looking at 32" from an well designed, very efficient,
setup.

Are you using a breakout point on your toroid? It will greatly increase the
lengths of sparks.

28 ga wire is pretty fine, so resistive losses are signficant.
your biggest loss is probably in your saltwater caps.


> 
> The secondary is 28" of 28-guage wire wound on 4" pvc. I realize this is
> 
> My primary is about 16 turns of 1/4" copper pipe spaced 1/4" apart.
> According QuickTC, My tap point won't be until around turn 20 or so. This is
> what I'm thinking is probably the key reason for my small discharges.

Possibly.. do the sparks keep getting longer as you tap out farther? or
does it peak, and then fall off?


> 
> So, what can I do to get nice BIG sparks? First of all, I'm going to add
> another 4 SW caps.

That will help bring down the number of turns needed on the primary, as
well as increasing the "energy per bang" which is also important.

> better results, I'll look into doing that. Also, it's just grounded to mains
> ground. I'm sure this impacts performance, but I'm also sure this alone
> isn't the reason for my minimal sparks (I can't work outside right now, so I
> have no other choice).


Depending on what the connection to the ground your coil is sitting on
looks like, a better ground will make a bunch of difference.  Try a 3-4
foot square ground plane under the coil (connect it to the safety ground
too). Chicken wire, aluminum foil, copper sheet, almost anything will work.