Hi Steve,
Yeah, I brought that up recently about the variac. I was using a Staco 10
amper. Their spec sheets also say can be overloaded. But for me it did not
like it at all going by my ear (sounded very bad) and I did not see hardly
any gains, no matter the few tuning changes I tried. Did not want to run
long either for the health of variac. So I decided to quit messing around
and get out the bigger one. It also affected the MOT for me, it was noisier
also. So despite what variac spec sheets say about overload conditions, I
have switched to larger variac that I also mentioned recently. Now a 20 amp
Superior Electric Powerstat. Again with this, much quieter. The MOT also.
Unfortunately, yes it is bigger, taking up more room. But I want to push
this coil further and I saw this for me as one of the major roadblocks.
There was other things of course, but I am getting past them too. Been
making nothing but gains all the way so far. Actually I thought 25" was
going to be max for me with the T-200 tube using a MOT for the transformer.
For those that have not been following everything, this is somewhat similar
to a 810. So, I'm a bit smaller than a 833-A. Of course, I cannot run full
tilt long. But the point of this coil to me is all about getting the most
out of it utilizing the advantages of pulsing.
At the minimum, yes should be 24" for a 833-A. Heck, I was happy when I was
at 18" for my tube which was not that long ago, until I really started
messing with it because of you fellas on here having problems and trying
things myself related to our discussions. Just want to say again, I am also
just using #14 NST wire on the primary. I have bigger tubes that are a bit
more powerful than a 833-A
that I could switch to right now, same socket size, but I want to keep
using this tube. No real big advantage using my bigger tubes using the
current MOT for the transformer, except being able to run at higher tilt
rates. Actually with a MOT, they would be under utilized in my opinion.
Best for a future project with a proper big plate transformer. Got some big
fellas. But these MOTs work surprisingly well, I used to doubt them.
Could be a problem in conjunction with your current MOT also. If I am
correct, I think you are still using the NON-Advance MOT. I can't say for
sure on this.
My longest arcs are always at lower rates also, seems to like some "speed"
but not too much also.
I understand your portability problem.
My coil is now anything but. Takes up the whole workbench top now with
everything and meters to monitor things currently. But I am able to make
big changes no problem.
You are going to have to make a choice I guess. Try the cap first and back
off on inductance if needed since you are tight on space of your setup.
Easy to try.
Try lowering grid resistance more also, like we talked about earlier also.
I will give details more later on my current resistance, still
experimenting, not set yet for sure. You may cringe, when I tell you :-)
A lot of rambling here, hope it makes sense.
Okay, back to the new goal of 30" :-)
Chris
Sent from my LG V20
On Sun, Mar 18, 2018, 12:35 PM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hi Chris,
>
> I wonder if the problem with my VTTC is the variac? My variac is the
> Superior Electric model 116C. This variac is rated at 10 amps but can be
> overloaded if the duty cycle is sufficient to allow cooling. Currently I am
> seeing maximum current pulses of about 15 amps at 140 volts at an
> interrupter period where I get my longest sparks. I am using this variac
> because it is small enough to fit into the chassis of my VTTC to make a
> portable unit. I have bigger variacs but one of those would have to located
> outside of the main chassis thus decreasing portability. From the
> information that I see in the Powerstat data sheets, this variac should be
> able to supply several times its rated current if the duty cycle is
> sufficiently low so I don't think that this is the problem.
>
> I should note that if I run the VTTC in CW mode, it will draw about 19
> amps at 140 volts. As I increase the on-time of the interrupter, the
> current draw will rise to about 19 amps max but I get my longest sparks at
> lower interrupter rates where the VTTC draws about 15 amps.
>
> Steve
> <https://www.pupman.com/mailman/listinfo/tesla>
>
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