50hz on 60hz

[lawbadman]

Hi, I have a question,

Is it OK to run a 60hz toroid on 50hz mains. I plan to buy a 120v 600VA 60 HZ toroid but I want to use it on 50 Hz mains. I know that the operating temprature might increase a bit, but are there any serious consequences?


Thanks
Lawrence

 

[tiroth]

It may be extremely hazardous if not designed for 50Hz operation.

 

[bobo1on1]

A transformer is always very close to saturation, using a 60 herz toroid on 50 herz might cause it to saturate and blow the fuse.
And then again it may work fine, be sure to use a fuse though.

 

[Dr. Photon]

I wouldn't worry about it. There shouldn't be that much difference betwen 50Hz and 60Hz operation. True, it will be more likely to saturate at 50 Hz, but if going from 60Hz to 50Hz causes the transformer o saturate and perform unsatisfactorily, you are probabally pretty close to the max load on it, and a bigger transformer would be prodent, anyways. I wouldn't wory about it.

 

[lawbadman]

Thanks for the replies but I am still not sure based on your answers,
tiroth says no way
bobo1on1 says maybe
Dr. Photon says dont worry about it

So I have no definate answer. Anyone else wanna help me out?

Or does someone have a 60 to 70 VCT >= 300VA toroid with 120VAC 50 Hz primary that they want to get rid of?


Thanks
Lawrence

 

[richie00boy]

Using a 50Hz transformer on 60Hz is fine.
Using a 60Hz transformer on 50Hz should not be done as the core may saturate = cook.

You failed to mention the voltage of the 50Hz line. Most 50Hz lines I think are 230V, if you connect your 115V transformer to that it will explode and you will die. Maybe

 

[Stocker]

Worst case is you lose a fuse and have to buy a new transformer... why not try it?

 

[tiroth]

Some cores are designed for 50/60Hz operation...some are not. You can try it, but it might fail. I would be very careful, that's all. You don't want to start a fire.

 

[gearheaddruid]

testing toroids.

Hi, the easiest way to test this is put a 50 or 60 watt light bulb in series with it. Do this without any load. If the bulb glows, you are probably going to overheat the transformer. If you have a metered variac even better. I use this to sort out the windings on multi primary transformers. slowly bring the voltage up untill there is a sudden rise in current draw. About 15% below that voltage is usually the designed running voltage for that winding. See if you can run up to full mains without any current draw. If so, you should be safe. Put a fuse in series with it, let it idle for an hour as you check temperature and current draw. If it is no more than warm, go for it. Regards, Steve

 

[lawbadman]

Thanks Guys I get the point.
I wont bother with a 60HZ toroid, just too risky, i want to keep my face just as it is.
I will go buy a 60/50 Hz toroid.


So now, can anyone tell me the name of a good, cheap source of toroids in the US, I really want to spend as little money as possible?


Thanks a bunch for all the replies.

Lawrence

 

[wa2ise]

For a first order approximation, the line frequency determines (for a given size core and number of turns) the max voltage it can handle. A 50Hz transformer can take 60/50 more voltage at 60Hz. Conversely, a 60Hz transformer can only take 50/60 as much voltage at 50Hz. Those combo 120/240V 50/60Hz transforemrs with the pair of primary windings are in reality 50Hz transformers. They can handle, at 60Hz, 6/5 more voltage, 144V or 288V. Not that you're likely to find that except somewheres in the 3rd world. Back 80 or so years ago some parts of the USA had 25Hz powerlines, and the occasional old radio set came with power transformers (big ones!) for 25Hz-50Hz-60Hz. That 25Hz 120V transformer can easily accept 240V 60Hz no sweat. Of course all the secondaries will provide twice their rated voltages.

The smaller transformer with the higher frequency is a big reason for switching power supplies. Those run in the tens of kilohertz. Though the core materials are different than that in 25-50-60 Hz transformers.