Steve, I have seen that smoking variac problem a couple of times and both
times were due to my wiring error.
If you somehow connect 120vac between the wiper and one end of the
winding, as you rotate the shaft the 120vac gets connected to fewer and fewer
turns until smoke is released.
Others have mentioned how to repair the unit.
73,
Gerald K5GW
In a message dated 12/26/2009 3:38:23 P.M. Central Standard Time,
K1SG@aol.com writes:
In pre-testing a junkbox Variac before using it for filament control, I
watched it arc and spark and burn out the winding near the high voltage
end.
Does anyone do Variac repair and rewinding? Or is that another "lost art?"
As a side question, I was running the variac into a step-up transformer,
which was unloaded. Does the primary of an unloaded transformer present a
significant load? Some Specifics: 5A Variac driving a 120:240VAC
transformer
of unknown power capability, weighing probably about 10 pounds. I know if
I
put a 2.5 A load on the 240V side, I'm drawing 5A through the primary, so
I'm staying well below that level. The question is, do winding
resistance,
core losses, etc, add a large enough load to fry the Variac in front of
the
transformer?
Thanks,
Steve
Steve Gilbert
K1SG
K1SG@AOL.com
508-435-9133
FN42fe
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|