I have a mains powered PIC based design that is intended for operation in the US 
but I want to test my prototypes here first. Local supply here in New Zealand is 
230V 50Hz.

I've tried a 230/115V transformer (measured 120V) but my PCB mount transformer 
on my board gets too hot for my liking (85 deg C, or 185 deg F, no load). FYI it is 
too hot to touch for more than a second or two!

I was expecting it to be warmer on 50Hz than 60Hz but not this warm. The 
transformers I'm using are Hammond 183G24, intended for universal operation, 
10VA, dual primary 115/230V, 50/60Hz, sec 2 x 12V. They have insulation rated to 
155 deg C, but should I expect it to run this hot? Surely my measured 120V is not to 
high? I've tried 5 transformers and they alll run about the same temp.

http://www.hammondmfg.com/183.htm

I've checked and double checked that my two primary windings are wired in parallel 
for 115V operation with the correct polarity, the output is also OK and my no load 
test above even had the secondaries completely disconneted. I will wire one up for 
230V operation now and check to see how hot it runs on 50Hz.

Trying to figure out a way of getting a 60Hz supply to test the transformer before I 
complain to the transformer manufacturer. I thought about 12V or 24V to mains 
inverters, but everything available here seems to be fixed 50Hz. Would also need to 
be a sine wave for a proper test, and with 100VA or more I could test my complete 
product.

Ideas? Thanks.
-- 
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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