Test: Bigger Secondary gives Bigger Sparks
Recently I posted my results from a small TC with a 3" by 12"
secondary which gave 14" sparks using a 7.5kV, 30ma NST,
120bps sync rotary gap, 13.3nF cap, and 3" x 10" toroid. The
#12 wire primary was tapped at 6.5 turns. A nice mini-TC.
I removed the small secondary and installed a larger 4.2" by 23"
secondary also wound with #28 wire. I retuned at 18 turns on
the primary as needed. All else remained the same, but the
spark increased to 22" for a 57% increase.
Other things that automatically changed; greater primary inductance
and surge impedance, greater secondary inductance and Cself,
lower frequency, no racing sparks. It is not known how much each
factor contributes to the 57% spark length improvement.
It is intriquing to consider that perhaps the spark lengths of many
other TC's could be easily but greatly improved, simply by installing
a larger secondary with greater inductance, and retuning as needed.