Daniel Dourneau wrote:
> 50 Hz or 60 Hz operation should not really make any difference.
> 
> What I cannot understand is why your transformer gets so hot in the
> first place. Is it under rated? What is your load current? What type
> of rectifier are you using (bridge, single diode)? What value is the
> capacitor.
> 
> One thing is sure, if you cannot touch it, its too hot and forget
> about any type of certification of your product (if you intend to
> apply for that)

Each winding of a transformer is an inductor, so 50Hz/60Hz does make a difference 
to the current that flows. Current will be higher at 50Hz because inductive reactance 
is lower (Ohms).

I tested it no load (open secondary). No diodes,caps or anything.

I agree: it's too hot. Perhaps the combination of 50Hz and 120V (slightly above the 
nominal 115V) pushes it to the edge of magnetic saturation and hence a dramatic 
increase in temperature. In that case I'm dissapointed. But I will test a bit further yet.

-- 
Brent Brown, Electronic Design Solutions
16 English Street, St Andrews,
Hamilton 3200, New Zealand
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eMail:  brent.brown@clear.net.nz


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