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10KV RMS -at- 300MA

Subject:      10KV RMS -at- 300MA
       Date:  Wed, 04 Jun 1997 14:16:05 -0700
       From:  Skip Greiner <sgreiner-at-wwnet-dot-com>
Organization: Greiner, Ltd.
         To:  tesla list <tesla-at-pupman-dot-com>


HI Ed Sonderman, Malcolm, John Freau and Barry Benson and All

Thank you all for your discussion. I have had a chance to reflect
further on these H&R trannies in light of your several comments.

1. These transformers are different from neons in that they were
designed
to be resonant transformers to raise the voltage. They also current
limit. I believe now (with some inputs from Robert Stephens) that
somehow the waveforms are being screwed up by rapidly discharging the
primary/resonant cap at different points in the mains sine wave, and
somehow, even though the transformers have the capacity to recharge the
cap quickly, this is not happening. This could explain my inability to
achieve higher power processing at increased break rates.

2. John, per your experience and mine with neons, the expected rise in
power drawn from the mains does not happen, at least as far as the
ammeter reading is concerned. It stays pretty constant even up to 700 to
800 pps when the spark length has pretty well dwindled to zero. There
may be some increase in the fatness of the spark at just above 120pps
but it is small. I am running the gap spacing quite small in order to
get a good consistent firing and I really can't reduce it.

3. Barry, I have run a primary cap as large as .107uf and as small as
.054 with reduced capability from the output when using .08uf. Again I
think this points to some kind of a resonating problem with the H&Rs
since it seems that a larger cap should help. By the way, what is the
largest discharge which you have achieved with a pair of these beasts? I
am not in a race with you...Just curious.

4. Malcolm, I have a rectifier type (homemade) meter across the HV
output of the trannies. As far as the meter is concerned, the output
voltage stays right at about 9.5kv. Anything above this causes the
safety gaps to fire. I do agree that the quality of the sparks is
somewhat different but it is hard to quantify. The sparks are somewhat
fatter and maybe a little bit wild but .....

So far I have not changed the coupling from that which gives the
greatest output at sync rates. But, a quick test indicated some
potentially strange results may occur. I dropped the secondary all of
the way into the cylindrical primary (from about 3" above it) and got
lots of discharge length and NO racing sparks at non-sync break rates.
More to come on this.

Skip