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On 12/4/20 10:37 AM, Forrest Mohrman wrote:
Shaun....have had the same problem with 4 different units. The brushes
corrode into place and allow arcing to the windings and the burn a turn.
You have to gently tap back and forth to get it loose......take you
time......it will come free.
When you are loose take the sides and lightly sand the corrosion off so
the brush so it slides freely in the slot. Might have to sand the slot
also. A nail file comes in handy. No oil! Can use graphite powder for
lube.
Bud
I'm not sure I'd use graphite powder (a conductor) as lube on a variac.
I'd go for some sort of contact cleaner/lube as used for things like
rotary switches.
But checking the Superior Electric or other variac maker website might
be useful.