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15kV-at-60ma vs. 7.5kV-at-120ma
From: FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: Sunday, July 27, 1997 8:46 AM
To: tesla-at-pupman-dot-com
Subject: 15kV-at-60ma vs. 7.5kV-at-120ma
All,
Previously I had done some work using a 15kV, 60ma (900VA)neon
trans with .014uf Cap, sync gap, 28 turn pri. and 6" x 26" toroid...this
set up gave 65" sparks at 2600 watts.
I wanted to compare the performance using a 7.5kV, 120ma (still
900VA) neon trans, with a larger cap. Yes, losses will be
higher in the tank circuit now. Yes, I could use thicker wire and
better connections and reduce losses, but I didn't bother.
First I installed the 7.5kV trans, a .056uf cap, and tuned at 9 turns.
Since I'm using #12 stranded pvc ins. wire, I obtained an arc-over
between the windings that did some damage. Spark was only about
12" long. Power draw was about 1900 watts. I could not continue
this approach without using a "better" primary.
Next, I removed some capacitance for a remaining total of .028uF.
This set up tuned at 18 turns and did not arc over. The TC gave
about 56" sparks and drew 1400 watts.
Final test used .042uf capacitance, tuned at 14 turns, drew 1750
watts, and gave 56" sparks. In both this test and the previous (above)
test, the needle that I press into the stranded primary as a tap point
got hot and melted the piece of poly plastic it was touching...HO...
Lots o' current here!
Anyhow, I thought the tests went quite well, losses were higher but
acceptable. The spark had no trouble jumping my 8 series gaps in
the rotary. Spark was shorter than at 15kV, but power draw was
lower also, so I'm not complaining.
John Freau