Adrian C wrote:
On 27/02/2014 07:52, harryagain wrote:


Both voltages are common in the USA. So it will be precisely for this
pupose.

Unlikely, me thinks. 240V in the states would be used for high power
items that would otherwise draw too much current at 110/120V. This class
of item wouldn't fall into that use category, 240V wouldn't necessarily
be plumbed in at the environment of use (studio, lounge etc...).

More than likely the choice of transformer is commonly in international
use. However the designer might not have sized the device for 50Hz use,
even though the provided windings are configurable. And then there's
other components. Ratings of capacitors, rectifiers, EMI filters and
insulation / creepage distance.

So all that needs checking to be safe. You are right about consulting
documentation.


As the product is described as 50/60Hz. It is very unlikely that two
different transformer cores will be used. Also, 110/120V products have
to withstand up to about 150V in operation because of the US
distribution system of very long lines and the resulting poor
regulation. I can't recall the exact voltage ranges we designed for in
120V PSUs, but I reckon it was 80 to 160V. My experience is that I've
yet to see a US consumer transformer fail due to core saturaton at 50Hz.
I generally buy US ceiling fans for summer use and none of these have
yet shown any signs of overheating.