Transformer frequency

[simpsonmichael]

We specified a 125KVA 440V/220V transformer at 60Hz. It has arrived however at 50 Hz. I know the change in frequency will alter the reactance therefore the impedance, with the net result being a change in current. Will this change the flux by to large a margin and harm the windings? Or can I use the transformer at 60Hz

 

[sibeen]

The flux density (B)is proportional to E/f. As f has decreased then the B has gone up. You would be wise to consult the manufacurer. Many transformers are made to cope with both 50 and 60 Hz.

 

[waross]

The V/Hz ratio willbe lower and the transformer will be better able to cope with over voltages. The saturation curve will be moved to a higher voltage by the ratio of 60/50.

Bill
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"Why not the best?"
Jimmy Carter

 

[ScottyUK]

... but the core losses will be higher because they occur as an amount of energy lost per cycle and you will have more cycles per unit time at 60Hz than at 50Hz. The effect is probably balanced to some extent by the lower flux density, but best answer is to ask the people who designed it.


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If we learn from our mistakes I'm getting a great education!

 

[Marmite]

A transformer designed for 50Hz can be operated at 60Hz, but not vice versa.
Regards
Marmite

 

[sibeen]

The effect is probably balanced to some extent by the lower flux density

Lower? Scotty, wan't to try that again?

 

[ScottyUK]

Higher frequency = more core heating (more power loss because of increased number of magnetic field reversals in the core iron per unit time)
Lower flux density = less core heating (smaller B-H loop)
Overall effect = no change (in a perfect world!)

Am I losing it or are you?


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If we learn from our mistakes I'm getting a great education!

 

[itsmoked]

It will carry 5/6th of the original design load won't it?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ScottyUK]

Yeah, same current rating and 5/6th voltage.


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If we learn from our mistakes I'm getting a great education!

 

[waross]

I think that the possible voltage ratio going from 50 Hz to 60 Hz is 6/5, not 5/6.
In this case, the rated voltage at 50 Hz is the correct voltage for 60 Hz so the ratio will be 1/1. 440 at 50 Hz, 440 at 60 Hz. No derating. (And no increased capacity as there is no voltage change.)
Higher frequency means higher inductive reactance and less magnetizing current. I'll defer to Scotty on overall losses.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Your right Bill. I thought a 60Hz xfrmr was going into 50Hz.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[lansford]

At a coal mine where I worked, we had a lot of 25 Hz power transformers used on 60 Hz. They worked well and the only significant issue was that the Z was much higher on 60 Hz (since most of the Z is Xl)
JIM