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Re: 50 KVA Power Supply

I wrote:

 > Running the pair up to 280 volts input resulted in only the
 > slightest hum. Gone is the growl of the stressed and saturated
 > 7200 volt pig ramped up to 14,400 volts by doubling up the
 > primary and running 240 volts into the 120 volt windings.

Quoting Brent Turner:

> I expect some heavy-duty, serious smoke (aka performance) from
> this coil...gonna post pictures??

The pics come in flushes as I get things done. What I am really
working on now is a general purpose power supply for driving a
variety of coil systems from medium to large with the bottom end
being around 2 kVA and the sky being the limit. I am well
equipped with a number of high-rep pulse capacitors (both
homemade and commercial), but until now I lacked a good selection
of step-up transformers in the requisite voltages. 

I had acquired a heavy pair of 5000 volt plate transformers which
I placed in series/parallel for a decent 10KV power supply. I
already owned the 22890 volt 10 KVA pig. For voltages in between,
typically 12-15KV, I was stuck using paralleled banks of neons
(which I still maintain). This presented a problem for a long
time as most of my capacitance was suited for 12-15KV operation
(I place my homemade caps in series), and this seems an ideal
voltage range to run medium sized systems and experiments. As we
have oft discussed here, neons are simply too delicate for the
abuse that a serious experimenter deals out. Bipolar, Magnifiers,
ground current transmission systems, etc., kept me as busy
spending time tending to my neon bank as I was spending on the
high frequency coil side. Large neon banks will also nickel and
dime you to death over the long run if you let them.

Now I got a huge bargin, right off the back of the truck, on
25KVA single bushing pig. I planned on re-wiring the pig and
running it over-voltaged for the 14,400 volts I really need.
Alas, the rewired pig proved unstable when run overvoltaged,
apparently due to the saturation problem. Careful ballasting
would control the problem, which exhibited itself as powerful
current surges through the control wiring and variacs, but it
became clear after some testing that the rewired/overvoltaged pig
was not suitable as a "general purpose" power supply for running
numerous systems and configurations as I had hoped. Again, the
time spent fiddling with the ballasting and variac settings was
time subtracted from the actual work. 

So I bought the second pig to match the first, wired them in
series/parallel, and hopefully have gotten this problem resolved.
Though the solution was not pretty (a 10KVA two bushing pig would
have been perfectly suitable and cheaper), my setup should work
fine now. I certainly don't think I have to worry about a weak
transformer suppling my experiments. 

Richard Quick


... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12