Hi all,
First off I want to reference this just posted thread:
Mains Staccato / SGTC
So after the success of this...
I again got to wondering on one of my VTTC's. Specifically my "new" old
T-200 one. This coil also has origins in the 1980's also. This coil is
normally run on just normal AC with a fairly heavy plate transformer(38
lbs). I have run this coil with my now modified German Staccato controller
and a SSR switching the cathode like normal. Works great and everything
nice and smooth running. Single shots and burst modes all work great. Now
this coil does not get very good swords. The frequency is about 100kHz too
high. This coil never originally back then had this in mind at all. But it
does have interesting bushy sparks though.
So I have decided to try hooking up the SSR to the 120vac mains input on
the plate transformer. Going to switch the primary of the transformer
direct again. And pretty much as expected, this works great. SSR zero
crossover working very well. Any controller changes are very smooth and
very responsive. This coil puts out about a maximum 20" sparks at times.
I have a link to a few pictures of this setup and a video I took of this
running this way:
https://photos.app.goo.gl/fMz5gAGDmjMpvq5P9
I want to say this my even seem to run even smoother than before.
Also the plate transformer runs now even cooler than before, since again
not constantly energized. I have also run this coil many times now no
problem this way. Some runs over 2 hours even.
I currently do not remember the idle current of this transformer, but it
not much when I last checked. Now this transformer when the tube cathode
was switched, it would get a little warm. Now running this way barely warm
at all. Actually maybe a little surprised some here.
And a final note here, this way will not work for a level shifted supply.
I thought about this because of the charge capacitor will not charge up
properly. Decided to do a slightly risky test just to be sure. I took the
removed bigger old MOT with a level shifter that is now removed and not
going to be used anymore on the 304 coil and test on this T-200.
As I thought this does not work well at all! Got some strange occasional
small poor sparks. Did not run long for fear of hurting something.
Next I hooked this up for regular cathode switching and the coil would now
get 27" sparks maximum. But this is pushing this old coil very hard.
Primary wire especially. It is not very big wire at all!!! Gets quite hot
now.
Tube does fairly ok. And well since no fan on the MOT it heats up quite
quickly like they normally do. Just wanted to do a quick test this way
also, just to verify.
I put the plate transformer back on switching the primary again and let it
run for over an hour. Still all working great.
Chris Reeland
Ladd Illinois USA
Sent from my Samsung Galaxy Tab® S