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Re: [TCML] LTR/STR and spark length
Hi, and thank you to everyone for your responses-
Bart, it's very interesting that our coils are so very similar..... except
for that whole, underperforming thing on my part. Let me give you a little
more info on my specs before we go on.
My first topload was a dryer-duct, covered with foil tape, type, 19 3/4" X
I had arcs off of it, but from all over the place, even with a
screw/breakout point taped to it.
So for the moment, at least for consistency purposes, I'm sticking with a
10" ss sphere with a 12 5/16" steel rod inserted into it. All the arcs are
headed relatively straight up now.
My gap is single static, quenched with a blower/motor from a microwave. The
electrodes are round, "almost flat" surfaces, 1" across, made out of brass
(old drawer pulls). I'd like to stick with a ssg for now, but, if I feel
ambitious, I do have a couple little motors around that could probably give
me at least an asrg.
Since my last email I tweaked a couple things, and I'm getting easy 24+"
arcs now. I opened up the gap a little bit, but still backed off if I got
any arc on the safety gap. I also ground a mild point on the rod sticking
out of the sphere. Racing arcs were mentioned earlier, but the only time I
experienced them was very briefly while adjusting the primary tap.
*Could you explain how one goes about determining the resonance for a given
system, so that they could know (within the proverbial ballpark's range) as
to whether they are str/ltr/R? Thanks everyone,
Just thought I'd share my little coil with you since it's similar (4" x
20" these days) and uses a supply voltage about 10.6kV at 200mA (modified
12/60 NST), so similar to your power supply. I'm also running a static gap
on this coil. Early on and in the pics below I have had some primary
strikes but hardly get those any longer. In the pics (at the link below),
the coil ran with a rather tight coupling. Some months later after these
pics, I ended up catching the bottom of the secondary on fire (bottom
turns shorted). When I realized the glowing red spots, I decided to just
continue and let disaster happen (which did). I ended up removing about
1/2" of winding which also lowered coupling. The coil these days is
painted red, but nothing else has changed other than a slightly looser
coupling. No more problems with the sec bottom turns. This coil has also
ran very long runs (which I did mainly to verify coupling was good for
it's duration and I was curious as to how everything would do over a long
duration). I was happily surprised.
Well, I just wanted to show why I think your coil could probably do better
than it is now. BTW, the MMC is 18.8nF, so I also am running STR with this
setup. Other than maybe the gap and toroid, our coils are probably not
that different. Also, on this coil, I typically run about 90 to 100 volt
input via a variac to keep sparks out of harms way.
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