"Kalarama" wrote in message
...
"N_Cook" wrote in message
...
Something to do while watching some less engaging TV. Unwound another
large
toroidal mains transformer. Suspecting doubled up winding of the primary
and
then for UK use joining opposite ends and so relying on 2 thicknesses of
lacquer to resist high voltage. Of course somewhere near the middle at
some
point it fails catastrophically. Yes, burnt spot weld buried in the
middle
of the primary. Anyone know what this duff winding technique is called ?
(reduces the number of shuttle passes by 2 must be the reason). Is there
a
way of testing an unknown , but good , transformer for this winding
pattern ?
How come this wiring procedure is not outlawed ?
More generally, someone in production told me that a "goodness" test for
a
mains transformer is an open secondaries, no load, monitoring of the
primary
current is useful, any truth/rationale in that. ?
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


Sounds like fun, in front of the telly, something I would do.

But.................

I would really worry about inhaling/handling the slightest amount of PCBs.
Especially if the unit was manufactured before the '70s. (@_@)


Was this PCB stuff overblown about being dangerous? I worked for
Westinghouse motor and transformer repair in the 40's. Was up to my elbows
some times in PCB oil on transformers. I am still here. As for all coils and
motor windings they were submerged in varnish over night. then drained and
baked. No failures. WW