I have now tested one of these transformers in the alternate configuration of 230V 
50Hz (2 x 115V primary windings in series).

It seems to be getting just as hot... approx 60 deg C (140 deg F), no load, after a 
couple of hours or so on the bench. Previous measurement of 80 deg C was with 
the transformer in a sealed plastic box (finnished product). Tends to discount the 
theory of miss-matched windings in parallel. Also not a single transformer problem - 
tried 5 or 6 so far.

If the phasing was out (and could only be 180 deg out) then I'd expect near zero 
output voltage and that's clearly not the case. ASFAICT the windings are intended 
to be used in parallel...

http://www.hammondmfg.com/5CHook.htm

Will try a single primary winding on 115V for comparison.

-- 
Brent Brown, Electronic Design Solutions
16 English Street, St Andrews,
Hamilton 3200, New Zealand
Ph: +64 7 849 0069
Fax: +64 7 849 0071
Cell: 027 433 4069
eMail:  brent.brown@clear.net.nz


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