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Don Young Don Young is offline
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Default Obtaining 460v from a "480 - 240" ACME Transformer


"Ignoramus20688" wrote in message
...
I have a plasma cutter that is slightly broken (Hypertherm 600 with
cracked torch-to-machine plug). The plasma cutter is 460 v only. (no
kidding). So it sat in my shed for a few years as I had no 460v.

I also have a Lincoln Idealarc DC-1500 welder which I need to test.
(1,500 amp, 1,800 lbs monster). (I want to be clear that whether I can
at all get any life out of it with a 10 kVa single phase transformer,
is not obvious)

This is the prelude.

The story is that one of the mystery devices that I brought turns out
to be what I long wanted to get, which is a 10 kVa ACME Transformer.

It is a multitap thing that allows buck/boost adjustments of a few
percent. It has various taps that I could use if, say, I have 490
volts input and want 240v output. It is nicely laid out inside a
hexagonal transformer box, whose windings are sealed with epoxy.

My first question is, am I correct in assuming that I could use it in
reverse to get 460v from 240, at some reduced kVa. Also, what is the
realistic kVa number I could get from it.

So, my thinking goes, to make it into a 240-460 transformer, I should
allow for some losses and wire it according to the diagram connection
for 480 volts. Then under load, and due to losses, the voltage would
drop a little to 460. Right?

The bonus question is whether this thing could power a 10 HP motor to
make three phase 460v.
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I think it will work fine and you should be able to draw 10 KVA if you have
adequate primary power. I don't think 10 KVA is going to do much for a 1500
ampere welder but it might give it a functional test at least.

Be very careful as you are dealing with not only a lethal voltage but also
enough power to make things exciting if something goes wrong.

Don Young