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Re: [TCML] X-ray transformer wiring help!

I have no experience with X-ray transformers, and I also don't recall
hearing of any success stories using such to power a TC.

The construction of your rotary spark gap is concerning.  The flying copper
wire electrodes woven into the plastic fan are going to get hot, melt the
wheel, and go flying off.  Sorry to be the Debbie Downer!

The mechanical tolerances of the gap electrodes look large, and I worry
about a break-rate too infrequent or irregular to guarantee a bang every
mains half-cycle.  If the break-rate is too infrequent, the transformer
will draw crazy-high current.

I would advise you to abandon the X-Ray power supply in favor of a simple
NST, and build an MMC capacitor and start off with a static spark gap.
While I admire a just-try-it willingness to experiment, TC's don't fare
well with just throwing spare parts at them and hoping it will work. You'll
just have to do the math.

Gary Lau

On Sun, Feb 21, 2021 at 3:29 PM Lux, Jim <jim@xxxxxxxxxxxxx> wrote:

> On 2/20/21 3:50 PM, Curt Wilson wrote:
> > My names Curt and I've been trying to get a tesla coil up and running
> for a
> > while now. I've used multiple power supplys such as four mots wired in
> > series parralell with a center tap ground but they did not last probably
> > due to being used for fractal wood burning prior. I have tried NST's but
> > they had the gcfi on them and only worked for the first few minutes. So
> now
> > I've moved onto a cathode/anode 80 kva x-ray transformer that feeds
> through
> > a bucket capacitor and into a bench grinder with a 6inch plastic fan
> wheel
> > that I wove solid copper wire through four of the fins and have a oil
> > burner point on with side for the pick ups. My primary coil is 9/16" x
> 1/8"
> > solid copper ribbon with 1"spacing between coils and my current secondary
> > is 4.5" pvc with two recycled 34 guage magnet wire soldered together and
> my
> > top load is two old chevy hubcaps hot glued together. I'm running a 30amp
> > variac 125v ac to regulated 125v ac and I can't get past about 30v with
> out
> > the fuse blowing. Just when the rotary gap starts to fire the fuse blows.
> > I've tried a mot with secondary shorted between the transformer and the
> > variac but it didn't seem to make a difference and I've tried a250 watt
> > 15ohm resistor first where the mot was then tried it between the
> > transformer and the primary. Both places it just heated up and would not
> > allow any spark at the gap. Any help with the wiring on the transformer
> or
> > variac or suggestions would be greatly appreciated! Thanks in advance.
> > https://photos.app.goo.gl/nPS9fMg36375yAXi8
> > _______________________________________________
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> > Tesla@xxxxxxxxxxxxxxxxxx
> > https://www.pupman.com/mailman/listinfo/tesla
> >
> What is your X-ray transformer output voltage?  Most Xray transformers
> have *very* high output voltage compared to what's practical for most
> home built TCs.
> Xray - 75-120kV isn't unusual.  Neon Sign Transformer (NST) or Pole
> Transformer are 12-15 kV.
> So you should be looking at feeding your Xray with around 10-20VAC.
> A real issue is that Xray transformers don't have any current limiting,
> so you'll need a ballast to limit the current (just like pole-pig designs).
> Does your Xray transformer have rectifiers?
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