Jeremy,
Yes the breakout point may have been allowing you to run with tighter
than normal coupling. Mostly likely raising the secondary will fix
the problem. I prefer to run without a bo point because the sparks
generally "look" better, and can move around the toroid if the toroid
is smooth. If there was any wind outside, that might
have been interfering with the streamers, but I'm not sure if that
would promote racing sparks. You could try re-tuning the primary
too if you didn't do that. Maybe the different environment outside
is affecting the tune-point. You may need to tune outwards a little
with the primary tap. If the primary is tuned too much inward that
can definitely cause racing sparks over a large portion of the
secondary. I don't think adding a small extra toroid will help,
but I'm not sure.
Your secondary is quite large so I'm surprised you got racing sparks
at all, of course it could be quite over-coupled. With suitable coupling,
I don't think you'll get any racing sparks. On my TT-42 coil,
when I installed a larger than normal 6" x 24" toroid, the sparks
were only able to break out intermittently without a bo point, but
there were no racing sparks even with no bo at all. Yet my coupling
is not overly loose. I know this because it was originally too tight and
got racing sparks even with a 4" x 13" toroid. I had to loosen the
coupling enough to fix that. But still there were no racing sparks
when I tried the coil with the larger 24" toroid, even when there was
no bo at all. I was able to get longer sparks without the bo point
using the 24" sparks, but bo was intermittent. Generally if the
spark breaks out easily without a bo point, then the sparks
will be no longer than with a bo point.
There's also the question of where your racing sparks appear.
If they appear near the middle or top of the secondary, this could
be a tuning issue. But if they occur near the bottom of the
secondary, then it's most likely a coupling issue.
Sometimes spark gap quenching issues can cause racing sparks,
but I guess it's unlikely in your case since you're using the synch
rotary. These types of racing sparks tend to occur all over the
secondary.
Happy New Year to all,
John
-----Original Message-----
From: Jeremy Gassmann <jeremyee78@xxxxxxxxx>
To: Tesla List <tesla@xxxxxxxxxx>
Sent: Fri, Jan 3, 2014 3:32 pm
Subject: [TCML] Breakout point or no breakout point
Hello everyone,
Happy new year! To celebrate the new year this year, I gave a demo of
my coil to some friends (and neighbors if they were watching). I was
actually able to do it outside for the first time and tried taking off the
breakout point since I wasn't concerned where the streamers came out. When
I did this, however, I began getting racing sparks up the secondary. I know
that removing the breakout point increases the top load voltage by a
certain amount but I was surprised that it gave me the racing sparks issue
as I thought that was related to the primary-secondary coupling. So I guess
my question is...is it better to use a breakout point or can you typically
get longer streamers without it since the voltage would be higher? How do I
fix the racing sparks issue in the no breakout case? Simply raise the
secondary some? Or would adding a smaller toroid under my main toroid but
closer to the secondary help control the fields some? I know I would have
to retune the primary some in this case but thought it might be worth it.
Or would it even be better to just use the smaller top load?
Here is a quick description of my coil: NST driven (15 kV, 120 mA total),
0.04 uF MMC, 8" x 36" secondary, large top load is 7" x 29" and smaller
toroid is 4" x 22", spark gap is a synchronous rotary gap. If I missed any
thing, please let me know. Thanks a lot in advance!
Jeremy Gassmann
Cincinnati, Oh
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