Variac

[Gordon C. LaGrange]

Sorry for the delay in answering, but I was waiting for tropical storm
Allison to pass over.

First - many thanks for all the replies, especially from the safety angle. 
I'm assembling them in one document so I can consider everything during the
construction.  

More info: I pulled an old megger from the dark corners of the shack and
found that on the 1 Kv scale there was 400 Megs leakage from the winding to
the control shaft.  So the single layer thin insulating sheet seems to
fullfill its purpose.  I happened to notice that on the back side there
were 2 layers separating the windings from the metal framework. There is an
insulated coupling for the wiper arm.

The isolating transformer I will use was designed for that purpose. The
disassembling of my old homebrewed unit (giant B & W television transformer
with all the secondaries removed and rewound ~ 1960) and construction of
this one will probably take a few weeks, so I'll stay open for suggestions.
Gordon W5AKQ

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