60C doesn't seem out of line, and should not damage your transformers. =20
But an isolation transformer on your scope serves no useful purpose. =20
Any modern scope will have a transformer inside already.  Line and=20
neutral will be connected only to the primary of the transformer (and=20
on/off switch).  Bypassing the safety ground (3rd prong) does exactly=20
the same thing as using an isolation transformer.  The problem is, this=20
lets the exposed metal parts of the scope (such as BNC connectors)=20
assume whatever voltage the probe ground clips are attached to. VERY=20
dangerous.

FAR safer would be to run the circuitry under test from the isolation=20
transformer.

Kerry



Electron wrote:
> Hello,
> is it normal that an isolation transformer gets very hot (~60C) even with=
out
> a load?
>
> I have built one using two spare 160VA transformers: 230V->32V =3D 32V->2=
30V of
> course the two transformers are identical, just wired as pri->sec=3Dsec->=
pri
>
> I needed it since my oscilloscope is not isolated from ground, and this m=
akes
> some measuring impossibile without the isolation transformer.
>
> Meanwhile I noticed that my 'scope is CAT II, i.e. designed to work on ci=
rcuits
> directly connected to the low-voltage installation (MAINS).
>
> Could there be any problems about floating the ground connection on mains
> powered scopes? I have been using it this way for days but I haven't died
> yet, was it just out of luck? :D However I get much more "usefulness" fro=
m
> my scope through the isolation transformer and no ground. :P
>
> But then I thought: did I really need the isolation transformer? Couldn't
> I just cut the 'scope's ground wire instead?? :P
>
> With kind regards,
> Mario
>
>  =20

--=20
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