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50 KVA Power Supply



I wrote:

 > I picked up the new pig today, I will have to get it wired and
 > fired to find out if things are different/better now.

Jim said:

> I look forward to your results.

Well, we will see how it goes. My brother and I wrestled the new
pig (can you say "rodeo") out of his truck and up onto the engine
cart next to it's mate. After grounding both cans with some strap
and using some No. 4 AWG cable to parallel both LV windings, I
connected the two pigs to the power cabinet and began some low
power testing.

With every bit of ballast I could muster, I ran the variacs up to
100 volts and heard a slight hum from the pigs. Not a good sign.
After turning the power off I rolled the cart around so I could
approach the HV bushings and placed an insulated platform on the
floor. Going back to the cabinet I powered the LV windings up to
100 volts. With the primaries live I stood on the platform with a
length of HV insulated wire in my hands. I approached the HV
bushings one at a time with one end of the bared conductor. A
slight crackle assured me of standing HV on the bushings, but
carefully bridging both HV bushings failed to produce an arc. 
I was out of phase.

After reversing the phasing on the LV windings I opened the
variacs back up to 100 volts and the humming was gone. Bridging
the HV bushings with the HV wire (while standing on the insulated
platform) resulted in a nice 60 cycle arc about six inches long
and as thick as a pencil. Pulling the arc upwards from the
terminal I could sustain a six inch arc indefinitely. 

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.

Alas, along with the new pig, a clothes washer also arrived in my
brother's truck. Until I get the washer moved out of the garage
and into the basement, I don't have room to fire up a coil. Give
me a couple of more days. However, so far so good.

Richard Quick


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