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RE: Latest coil
At 11:24 PM 09/07/1999 -0600, Tesla List wrote:
Hi Alan, Gary, all,
In my case as with Gary Lau, we've been using added
caps into the tank circuit. With two .01 mfd caps in
parallel, the coil practically roars at the topload. The
streamers aren't as long, but boy are they thick and
snapping.
I had removed the extra .01 mfd cap sometime back to
do experiments with a smaller topload. In the interim, I had
determined the coil was a little on the under-coupled side,
so I lowered the secondary until turn #11 was even with
primary. It made a difference. I wasn't getting racing
sparks at all and the streamers were more plentiful with
a smaller topload. When I went to using both .01 mfd caps
together last weekend, because of the tighter coupling,
the combined caps proved to be too much for the coil
in it's present state and I got racing sparks all down
the secondary. I didn't run the coil long enough to cause
any damage, thankfully. I think if you were to let a coil
run long enough with racing sparks evident, it will burn
wire on the secondary, and could cause a fire. It could
be the gazillions of coats of polyurethane varnish I have
on my coil that helped, but it was probably the speed in
which I yanked the power cord from the wallplug that
saved it from damage.
I do have a burn spot on the very bottom of my secondary,
although it wasn't caused by racing sparks, but by my own
stupidity. No wire got burnt. What happenned was I thought
I could use a giant metal hose clamp to grip the 4" wide copper
ground strap to the bottom of the RF connection on the
secondary. It worked, but arcs LOVED it too, so after one run
where I definately saw an arc leap right down to the metal,
I shut down and surveyed the damage - a 1" wide burn
spot on the very bottom of the PVC along the top of where
the clamp was located. The clamp was very hot. I removed
the clamp and went to using a series of rubber bands to secure
the RF ground strap and I've had no further problems. That was
a definite "I won't do THAT again" moment. <g>
As far as the racing sparks, if it were a surge from the NST at
power-up of the coil, I would think it would not last long. If
the sparks are coupling related, what do you do if you have
lifted the secondary WAY up past the primary and are still getting
the racing sparks? This seems to be a tricky issue. You could
build the secondary a little taller, but that's no guarantee you
won't still have this happen.
In the first couple of runs on my coil after the tank circuit was
connected up, I did get racing sparks but this went away after
I adjusted the toroid height, since I had it way too high. But
with using .02 mfd on the coil, the tighter coupling rather than
the toroid height, is the issue now when using both caps together.
I'd like to solve the racing sparks issue since when I start using
a pig on the coil and add more caps in the circuit, the problem
isn't likely to go away. I may have to try winding a taller secondary
to see if that will have any effect.
I've been reading Tesla's Colorado Springs notes and am wondering
if using an extra coil would solve this problem?
================================================
>Original Poster: ajones-at-pointlink-dot-net
>>Do the racing sparks happen the entire run, or do you
>>notice it at a few seconds into power-up? Mine were the
>>entire (brief) run.
>
>>Don
>
>The entire run, and each was brief, at the most five seconds. That's
>all it took to let the smoke out of the wires and create more work for
>me. I'll try again tomorrow night if I can, using some of the
>suggestions I have gotten.
>
>Did you burn any wire on the secondary or did you shut down quickly
>enough to prevent it? Will racing sparks always cause burning or did I
>let it run too long?
>
>Alan
>
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