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Fox's Mercantile Fox's Mercantile is offline
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Default Repairing A Variac

On 5/1/18 9:15 AM, wrote:
I keep two Heathkit IP 5220 Iso-Variacs A small write-up
with pictures is attached below (not mine).

http://www.byan-roper.org/steve/stev...-variable.html

Those are nice, but a bit undersized for what I work on.

So I bought a 20 amp Sola "Harmonically balanced" (four
winding) constant voltage transformer. From about 85-145 v
it will hold a steady 120 v and a reasonable looking sine
wave.
I put a three position "center off" switch on the front
panel to select "Line Neutral" "Floating" or "Line Ground"
for the "neutral" line on the output.
Following that, I put a 20 amp Variac wired for 10% boost at
max.
Then came the metering.
0-150 vac meter, 0-30 amp ac meter, and a 4-wire 3000 watt
ac dynomometer or direct reading of the load in watts.

Just for good measure, all the cords, plugs and outlets
are rated at 20 amps.

I also have a 2500 watt 400 Hz inverter for working on old
aircraft equipment.

If you're going to do something, do it right.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com