Re: but all the transformers do it

Wally K. replys;

For your application a stepdown transformer with 2 seperate windings
is a isolation transformer.

Sometimes isolation transformers have special shields around there
windings to reduce stray noise. But i do not see how this could
affect you.

--- In CAD_CAM_EDM_DRO@egroups.com, jmw@c... wrote:
> (Disclaimer: I know I'm electronically impaired.)Why isn't it the
> case that all transformers are not isolation transformers? The wire
> in the primary and secondary coils is insulated -- and so isolated -
-
> right? Don't the sparks only cross the divide via induction?
(Talking
> plain vanilla single phase VAC here.)
>
> The answer must be something to with the grounding or treatment
> of "netral" whatever that means. My AC understanding is limited to
> the notion of a sine function.
>
> In any event, I'd like to avoid laying out big $ for big isolation
> transformers. I've got to knock down the service voltage (110 or
220)
> to 70VAC to feed my servo amps--can an ordinary transformer be
> converted to an isolation transformer by ordinary methods?
>
> Alternative 2. Big 110 to 110 isolation units don't seem to be that
> hard to find surplus, and neither do ordinary transformers (110 or
> 220) --> 70. So presumably one could cascade the two to make a 70V
> secondary isolation transformer--but which one should go first?
Does
> it matter?
>
> The little Bport CNC retrofit project is well on the way to a rack
> mount cabinet. I didn't think this would happen.
>
> Thanks in advance.