120volt 50 Hz mains input

[Jason Marsha]

I noticed that the sellers of toroidal transformer power supplies show their output based on 120 volt 60Hz input, what happens to the power supply output voltage when the input voltage is 120volt 50Hz as I have here in Barbados.

http://www.kelinginc.net/KL-5020.pdf

The above power supply shows

input 120Vac 60 Hz gives output of 51 volts DC output

input 120Vac 50 Hz gives output of __? volts DC ouput

I do not want to smoke the G540 when I order it.

Jason

[Mariss Freimanis]

It will have the same voltage. The mains frequency doesn't affect the voltage.

Mariss

[Jason Marsha]

Thanks Mariss.

The reason I had originally asked is that I had seen some info on the web about a lower input frequency increasing the flux density and thought this would lead to a higher than stated output voltage.

Jason

[Pandinus]

A transformer may have the same output voltage but will not have the same output capability... A lower frequency has a negative effect on the output power available... this is why high frequency switching power supplies only need a very small transformer...


From http://www.smeter.net/daily-facts/4/fact15.php

50 Hz vs. 60 Hz Power Transformers
April 15th Fact-of-the-Day

More iron and/or more turns of wire are required to have the same transformer winding inductive reactance at a lower frequency. Iron-core and copper-wire both cost money and take physical space, so transformer designers generally use no more of either than necessary to keep power losses reasonable at an intended operating frequency. As a result, power transformers designed for use in U.S. 60 Hz applications typically run very hot, and sometimes extremely hot, if used in countries that have 50 Hz power mains, even if they have windings to accommodate the higher voltages that also are used in most 50 Hz countries. Long-time U.S. suppliers to Europe and other parts of world with 50 Hz power know better, but U.S. companies that are just starting to offer their products internationally very often have major problems with power transformer overheating. ©2005 Tigertek, Inc. All rights reserved.


From http://www.toroid.com/custom_transfo...bulletin_2.htm

A 60Hz transformer has 20% higher rated power than a 50Hz transformer of the same size and weight.



I'm just adding that I don't know exactly what the lower Frequency will do over all, but I think you should probably expect the voltage to drop off a little faster than the amperage ratings in the PDF and expect less available current overall.

[Mariss Freimanis]

You are correct, everything being equal a 50Hz transformer has to have 20% more iron than a 60Hz transformer for the same VA rating. That said, most transformers are 50Hz/60Hz rated. The main difference is the magnetizing current in the primary will be a little higher at 50Hz and the transformer will be a little warmer.

Mariss