Ivan Vegvary wrote:


Purchased used Variac. Good action, very smooth from 0 to 140V AC.

Question: Input and output are both 2 prong, no ground.
Should I modify it to three prong with ground?


** Yes - all modern ones are made like that. It is not safe to de-earth an appliance just because you need to use a Variac with it.


BTW, I do also own a functioning isolation transformer.
Should the IXformer be placed between the mains and the Variac?
Please advise as to best procedure.


** Either way works, feeding 140VAC to the Iso may get it a bit hot though.


Main use of Variac will be to power up ancient tube equipment.


** I use mine for almost everything.

Cos I hate blowing fuses at switch-on.


..... Phil