Re: Coil Woes

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Jim,


 > Original poster: JBarrett-at-trumbullcorp-dot-com
 >
 > My question today concerns transformer to capacitor match. I input the
data
 > into three separate programs and got three completely different
 > answers.  The values of the transformer are as follows; Input 120 volts 60
 > Hz and the output is 12,000 volts at 30-ma. NST. Initially I built an mmc
 > of 0.007 uf , 20,000 volts. Several people have suggested that I need a
 > 0.01 uf cap to power my coil. How is this value obtained?

One 12KV 30ma transformer will resonant at 60 Hz with a 6.6 nf cap.

Cres(nf) = 10^9/(2*pi*line_freq*XL)  where XL ~= 12000V/30ma

If is common practice to avoid resonant charging by using a LTR (larger than
resonant) cap.

for static gaps Cltr = 1.6 * Cres (give you about 120BPS)
for SRSG        Cltr = 2.8 * Cres  (at 120 BPS)

0.01uf would be 1.5 * Cres.

As you add more 12K/30 NST, add 0.01 for each extra NST.

Gerry R.