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Question:

Transformers and frequency question?

An AC generator, originally designed to provide a peak output voltage of ± 155 V at a frequency of 60 Hz, is required to provide a peak output of ± 340 V at 50 Hz. If the generator is connected to a transformer with 200 loops in its primary coil, how many loops should there be in the secondary coil in order to provide the required output?Using the formula Np/VpNs/Vs I get 439 coils, but this is too easy for a 6 mark question and doesn't include the change of frequency. I have no idea what to do and need some help :(

Answer:

A transformer cannot change frequency. You can change the voltage from 155 v peak to 340 volts peak, but you cannot change the frequency. But you can change the speed of the generator and therefore change the frequency, but I don't know if that is part of the question. usually, I find that if you list the entire question with all the details, then it probably could be answered. But only part of the question will lead to incorrect answers. .
Your answer is correct. The frequency has no effect on the turns ratio. The frequency does effect the required primary inductance, however. More turns with 50Hz, about 20% more for same magnetizing current as with 60Hz. I am assuming your generator can change frequency.
Transformers cannot change the frequency of an electrical signalperiod. It requires more sophisticated electronics to do that. Perhaps your instructor is confused.

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