Transformer

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Bang said:
What are some of the possible effects of running a 60Hz Transformer on 50Hz or vice versa?
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Not much difference going 60Hz design on a 50Hz system, that's what the "50/60Hz" designs really are. But if it is designed strictly for a 50Hz system and given 60Hz, then it can saturate and run hot. That usually leads to an early demise.
 
Jraef said:
Not much difference going 60Hz design on a 50Hz system, that's what the "50/60Hz" designs really are. But if it is designed strictly for a 50Hz system and given 60Hz, then it can saturate and run hot. That usually leads to an early demise.
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All of the references that I can find seem to state just the opposite. Since the 50 Hz waveform will have a longer period, it will result in a higher idle current flowing and a greater magnetic field, so there is a risk of saturation.
But a 50 Hz transformer will have more iron in it and will be perfectly happy with the lower excitation current that 60 Hz will produce.

You can probably convince yourself of this by thinking of the idling, unloaded, transformer as just an iron core inductor. The lower the frequency, the higher the current and therefore the greater magnetic field that has to be tolerated without saturation.
 
i suspect Jraef just didnt have his 2nd beer yet, and was thinking of a heavy customer problem when he wrote that.

you are correct. 50hz spec xfmr can run 60hz
60hz cannot run on 50hz w/o overheating
 
mike_kilroy said:
i suspect Jraef just didnt have his 2nd beer yet, and was thinking of a heavy customer problem when he wrote that.
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Or, he was thinking of control power/machine tool transformers, where most the new generation <3kVA units are often dual rated for frequency.
 
Bang said:
What are some of the possible effects of running a 60Hz Transformer on 50Hz or vice versa?
Click to expand...

Unless the transformer is listed as 50/60hz a transformer rated for 60 should never be applied at 50hz.
The transformer will overheat if you should do so. The way that I look at it is is easier to explain that as you lower the frequency it is like going toward a DC current. A 60hz rated xfmr applied at 50, 25hz etc the lower the frequency the hotter the transformer we I'll get. In order to reduce the heating affect the transformer would have to be derated which would be difficult or impossible to get the transformer created by the xfmr mfr to do. It would require a nameplate change to reflect the application.
In reality a 50/60hz transformer is really a 50hz transformer because a 50hz can be applied at 60hz. Basically there is more iron or core material with a 50hz design to deal with the addition heating that is present at the lower frequency.
 
A transformer may be used on a moderatly HIGHER frequency than it was designed for, but should not be used on a lower frequency than designed for as the magnetising current will increase and lead to overheating.

The exception to this is if the voltage is also reduced in similar proportion to the frequency.
For example a transformer intended for 480 volts 60 cycles may be used on 400 volts 50 cycles.
This is of limited use in practice because the output voltage will be reduced in proportion and therefore almost certainly be an odd or non standard voltage.

Small transformers such as might be built into equipment are often dual rated so as to permit of use in both 50 cycle and 60 cycle countries. The extra materials consumed dont cost much for small transformers, and it saves the bother of making two versions.

Utility size transformers are invariably built for the frequency and the voltages used in the country of use. I doubt that many USA utility transformers are exported to Europe, unlike small transformers built into machinery.
 
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