Hi all,
I have some more updates here.
First off, I will give some more specifications of this old/new SGTC.
- NST 15 kV / 60 mA , GFCI now recently removed
- MMC is CDE / 942C20P15K / .150uF / 2 kV set up for a recommend static gap
LTR capacitance of .0150uF / 60 kV / using 90 CDE 's
- Dual tungsten .25" dia. spark gaps
- Spark gaps set at .18" ea. for a total of .36"
- Secondary is 4" x 34" winding of #22 AWG
- Secondary form and mount to base is 37"
- Total height from floor to top of current toroid is 41"
And speaking of current toroid, I mentioned earlier about testing more as I
have several spun aluminum ones on hand that I have collected over the
years. I will now list all that I have tried up to current one now.
Started small of course, then larger:
12" x 3" x 6" Inside Dia.
14" x 5" x 4" ID
18" x 4.5" x 9" ID
20" x 5" x 10" ID
And current one now:
24" x 6" x 12" ID
To get this current toroid to work properly, I knew I was going to have to
add more inductance. With the previous 20" toroid I was practically maxed
out on the big roller inductor tuned in properly. So I did some rough
calculations in my head and then mounted on top of the roller at one end
adding turns of .25" copper tubing, which is stiff enough to be self
supporting. My rough calculations came out pretty close with just a little
wiggle room left for minor "day to day" tuning if needed. This can be seen
in the updated setup pictures of how it is set up for now.
https://photos.app.goo.gl/y7yHnAPCkMtLP7fi7
I do now have a new secondary form on hand for this coil that I received a
few days ago. But I am not going to do any winding anytime soon. Going to
have to think awhile on several things. I mentioned previously that the
days where getting numbered for this fella. Besides the crystal growth
happening that I mentioned earlier, it is now starting to stress crack in
several areas even more. When I took this out of storage, there was just a
couple of cracked areas, now too numerous to count. This old
varnish/shellac from the early 1980's is "tired" now. I will keep using it
for now though, getting as much use as possible before it becomes a display
piece.
https://photos.app.goo.gl/NHkZMqFCmG5Tx1ap8
Getting back to the toroids, I kept getting improved performance which each
size increase with proper tuning in. So I of course started digging out all
of my toroids stashed around here...yeah...not all in one place...it is
tough to be completely organized with all my parts and stuff :-\
So...my coil with proper tuning just kept taking bigger toroids and I just
kept going until I got to my largest practical one of 24", which for me is
physically pushing it some in it's looks, but does work great.
My next larger spun aluminum toroid which is also my largest is completely
physically impractical at 42" x 10" x 22" ID.
The performance now with the 24" one is much improved, now strikes are very
common to my garbage can target and my fans get hit even more often. And
there are occasional strikes to the actual floor now. These floor strikes
in the arch they go in measure approximately 54" + at times.
Oh... still keeping tabs on run time...now total is 21 hours.
Here is a some video I just took with the 24" toroid, again mainly
adjusting the PW, studying these changes.
https://photos.app.goo.gl/MxHLoJ3K7VeeaACN8
And here is another video where I have removed the Staccato and running it
as a normal SGTC with the 24" toroid. I did not do any tuning changes at
all. It possibly could have used some, but I would say overall not too far
off. I decided to do this for the possibly interested. Of course for
several reasons, this is not a real long run.
https://photos.app.goo.gl/THA7NEZBqfqkGs9c6
I also again want to mention that the video does not get all and sounds
included.
Getting the video settings as best I can is a pain and getting additional
light required is a pain too on a crappy old tablet I am using for this
video. The microphone is overwhelmed too, nothing that I could find to
possiblity adjust. This is also compounded by my empty basement which
echoes something horrible. I am too scared to use anything too good to
shoot video. This old tablet has complained many a time for me now on this
SGTC.
Also coming when I have time, since I am currently done with big changes,
which I also mentioned earlier is some mains line current readings I was
asked about by one person. There will be an analog meter and scope
measurements coming.
Readings with Staccato and then without running as normal.
I will have to change around quite a bit of power cords so I can do this,
as the analog meter setup is currently too close to the coil to shoot video
of. And for my digital scope, I again need to change power cords around so
I can have it a safe distance away from coil.
Okay enough rambling for now...I think I have covered everything correctly,
I want to say for now.
Chris Reeland
Ladd Illinois USA
Sent from my Lenovo Tablet