At 16.11 2011.09.05, you wrote:
>You should understand that not all  transformers are NOT bidirectional!
>The primary is often well coupled to the core, and can excite the core wel=
l.
>THe secondary is a bit more isolated and can not excite the core as well.

Good to know. :P

Well, I also have two transformers from two broken identical Uninterruptibl=
e
Power Supplies, those should be bidirectional, I'll use them then.


>
>On Sep 5, 2011, at 9:40 AM, Electron wrote:
>
>>=20
>> Hello,
>> is it normal that an isolation transformer gets very hot (~60C) even wit=
hout
>> a load?
>>=20
>> I have built one using two spare 160VA transformers: 230V->32V =3D 32V->=
230V of
>> course the two transformers are identical, just wired as pri->sec=3Dsec-=
>pri
>>=20
>> I needed it since my oscilloscope is not isolated from ground, and this =
makes
>> some measuring impossibile without the isolation transformer.
>>=20
>> Meanwhile I noticed that my 'scope is CAT II, i.e. designed to work=20
>on circuits
>> directly connected to the low-voltage installation (MAINS).
>>=20
>> Could there be any problems about floating the ground connection on main=
s
>> powered scopes? I have been using it this way for days but I haven't die=
d
>> yet, was it just out of luck? :D However I get much more "usefulness" fr=
om
>> my scope through the isolation transformer and no ground. :P
>>=20
>> But then I thought: did I really need the isolation transformer? Couldn'=
t
>> I just cut the 'scope's ground wire instead?? :P
>>=20
>> With kind regards,
>> Mario
>>=20
>> --=20
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>
>  *
>  |  __O    Thomas C. Sefranek  wa1rhp@comcast.net
>  |_-\<,_   Amateur Radio Operator: WA1RHP
>  (*)/ (*)  Bicycle mobile on 145.41 MHz.
>
>ARRL Instructor, Technical Specialist, VE Contact.
>
>http://www.harvardrepeater.org
>
>
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