Can you use 60 Hz Field Transformer in 50 Hz supply?

The electrical impedance of the windings would be so different running at 400 Hz instead of 50 Hz that the transformer's output voltage and current-carrying capacity would be very different to what it was originally designed to handle.

The only safe way to experiment with a transformer that was designed to operate at standard mains voltage and frequency would be in an electronics laboratory.

In a laboratory a safe method of operation and the right equipment and test instruments could be used. The method would probably be to vary the transformer's: * load, starting from a high resistance value,

* supply voltage, starting from zero, and

* supply frequency, starting from 50 Hz so that the resulting output voltage and current could be measured. The test results could then be compared with theoretical calculations of what the effects are likely to be of using a supply frequency of 400 Hz instead of 50 Hz.