Transformer Design - Help required...

Hi All,

I have a problem and I need a solution / guidence for this.

I want to design a transformer (Iron core preferably) for the following application.

I have a 3-phase alternator, generating 3-phase voltage of approx 100 V AC. The output waveform is not a pure sine wave, but a quasi square wave. I need to take two phases out of the three available and step down the voltage to 45 V AC, which I am trying to do by a transformer. But since the alternator is a rotating machine, the frequency of the 3-phase AC waveform generated, is depending upon the speed of the alternator. From low speed to high speed, the frequency is varying from 0 to 300 Hz.

Now my problem is: What is the frequency of operation to be considered for designing the above mentioned step down transformer ?

It would be helpful, if somebody can throw some light into the theory of it and any suggestive study material is welcome.

Thanks in advance ..

You can take two phases from three available, but I doubt you can make transformer for 0Hz frequency. If you really have so low frequency it may be easier to rectify the generator's voltage, then use switching power supply circuit to generate whatever is necessary. In this case you even may use the power conditioner, PWM and so on. Then you may get good results.
You need to keep in mind the effect from unequal loading the phases. It may dramatically affect other phases output.

Best regards,
RF-OM