[R-390] Possible source for isolation transformers?

[Kenneth G. Gordon]

On 4 Jul 2007 at 14:56, Barry wrote:

> A VARIAC does not isolate.

No, it most certainly does not.

>  From what the other gentlemen on the list
> have indicated, the boxes advertised are an autotransformer (like a
> VARIAC but with a fixed tap point).  It, too, does not provide
> isolation.

Again, correct. I bought one of those off Ebay just to see, and it is an 
autotransformer.

Out at work, a "control transformer" showed up in my junk to be 
surplussed. Needless to say, I "surplussed" it to my shack, WITH the 
blessings of the powers that be.

It has two very heavy winding that can be wired for either 220 or 440 
input or output. As such, it can also be then used as 110/110, 110/220, 
and vic versa.

Trouble is, it weighs a LOT: probably on the order of at least 40 lbs.

I also have two 115 to 115 VAC isolation transformers, good for 15 
amps each. THOSE little jobs weighs 65 lbs each!

So, on that basis, true isolation transformers weigh a LOT more than 
the cheap autotransformer types.

Ken W7EKB