Re: Stumped at first light

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Josh,

Like the others have said, the primary turns should be increased. For 30mA 
transformer, I would stick to a .01uF to .02uF (10 to 20 nF). For something 
along this line, build a 12 turn primary (assumed flat) with your same 
spacing and tube size (both 0.25"). This will get you in the ball park from 
around 10nF and up allowing you the ability to tune in different cap sizes 
(whatever you decide on). I'm not keen on the resonant size of 66nF. The 
time to charge the cap to transformer voltage is 132ms. Quite long. With a 
10nF cap, the charge time is down to a comfortable 20ms.

If it was me, I would go with a 20nF, 4" x 16" topload (breakout point), 
and 12 turn primary (tapped about 8.6 turns [~237kHz loaded indoors]).

Take care,
Bart



Tesla list wrote:

>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><IBATOU2-at-aol-dot-com>
>
>   My class has built most of our coil and I am a little sceptical about 
> our capacitance calculations. We would very much like to fire it up, but 
> I think it needs a little fine tuning. Here is what we built: feed-12000v 
> NST -at- 30ma, adjustable spark gap built out of copper tubing, The primary 
> is 6 turns of 1/4" copper tubing with a 3/4" gap between turns, the 
> secondary is 1000 turns of 22 ga. magnet wire on 4" pvc with a heighth of 
> 26 5/8". We have an 8" gazing ball or 4" aluminum flex duct for a 
> topload. We built a strike rail around the primary out of  #2 bare 
> copper. Will this work, and what kind of capacitors do we need. Any help 
> would be greatly appreciated. Thanks.
>
>