Hi all,
I have some updates from more experimenting that I have done recently on
and off when I have time.
I have again modified my Staccato controller. After observing coil running
when run at maximum PW the number of successive 60 Hz cycles available
currently, I decided that I would like to have more. This would give me
even better adjustment PW range, further improving use on a SGTC. When I
took controller apart to do this, I decided to do this in a different way
that just changing the one capacitor to a larger value.
I decided to do this by a alternate action push button switch to add
additional capacitance when wanted. So this would give me a 2 stage
controller. Stage 1 better suited for VTTC use and Stage 2 better suited
for SGTC use. I also did this in a way for future possible capacitance
changes, by making a pair of remote wired capacitor sockets also. This way
I do not have to take controller completely apart and get the soldering
iron out for changes. Now as simple as removing a side cover, make a
change, ready to go in about 2 minutes. I did not take pictures, but it was
easy to do.
I did take pictures of scope results and current values used on schematic
section changed. As can been seen on scope pictures, when button is pushed
ON, I essentially have doubled the PW.
Minimum PW "OFF and ON" pictures:
https://photos.app.goo.gl/2tRtWZCVn4aAp2oJ9
Maximum PW "OFF and ON" pictures:
https://photos.app.goo.gl/hPM9N42yEYcwL6vK8
Couple of pictures of schematic section, notes and controller on bench
after modification testing. Small red button can be seen on side of
controller. No room on top because of PC board.
https://photos.app.goo.gl/9n6KzH5j1wSdWw6o9
Testing on running coil was successful and I am now getting the kind of
control that I hoped for, further enhancing Staccato use on SGTC. I did not
shoot any video of this on the coil at it's current...well..."known
compromises" state mentioned previously.
So then, I got to thinking of the current state coil is anyway for now
until I am ready sometime in the future to do a new proper secondary. Coil
really needs a larger toroid for better output, and better output would
utilize Staccato controller even better.
With the 12" by 3" toroid I am getting mostly up to 24" arcs on average and
occasionally 36" strikes to can. This is with breakout point, but short
streamers come out elsewhere all the time.
I actually have already run with several larger toroids in the recent past
on this coil. But with no tuning wiggle room left, they did not work well
as expected.
So then I decided since currently having the needed long lead length to
tune in for the 12" toroid... to on purpose still keep them and throw on
one of my big roller inductors I have, so I then can put on a larger toroid.
Keeping the long leads enables me to be out of strike range of coil when I
adjust the roller on the fly to tune in. I added an extension to the knob
that was on this roller. The bakelite knob was not safe at this RF voltage
level. Metal shaft coming out, it is attached to is "Hot". So I decided to
utilize my 304 VTTC old damaged acrylic secondary form as a safe knob
extension for it's "new life" :^) The roller was very quick and easy to
put on, hook to one existing long lead. One short jumper on roller itself.
One more lead to reattach to circuit. Less than 5 minutes, done. Now I can
put on larger toroid. I have put on a 18" by 4.5" toroid.
While this roller is out here, I know about the losses itself, but I want a
larger toroid. It is still better to be in proper tune and accept these
losses vs. being way out of tune.
Now when running coil first time with roller tuning in on the fly and
seeing the output increase/grow as tuning gets closer...then the GFCI in
the NST finally started to "complain" with this greater output and cut
everything out. Not surprised. Surprised it worked as long as it did
before. Was curious so left in at that time. As I said previously, luckily
not potted in to the transformer also in the usual black stuff they use. It
is in an empty portion of the metal case. So it was pretty easy to tear
this encased itself GFCI epoxy module out (was surprised by some small
rocks filler in the epoxy though, never seen this before...) and rewire the
NST. I then ran again and finished proper tuning.
Here is some pictures of the coil now after these changes:
https://photos.app.goo.gl/PSWMhkc5o1fUyVbC9
And finally a video of it as now. This video is not as long. Don't need to
prove long runs again. I am varying mostly PW trying different settings
experimenting. Some PRF changes, not much. I am mostly studying PW in this
video. Video does not completely capture all. And sounds included. "Sweet
spots" are found at times. Output now is very consistent 36" average and
occasional 48" strikes to can. There is a break out point and it can be
seen mainly here discharges. I can still occasionally see a few small ones
try to sneak out elsewhere occasionally at different settings.
Video:
https://photos.app.goo.gl/y6syey53HSWRuGYr5
With this current output now, when I finally do make a new secondary, I
will have to be rethinking the whole layout and see what I figure out.
There is no strike rail down low. The 2 @ 120 VAC fans are serving as a
strike "rail" now. They are metal and are RF grounded and get hit fairly
often now. This old/new coil in it's original origins could never even
dream of possibly needing a strike rail.
Chris Reeland
Ladd Illinois USA
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