Converting 400Hz AC to 60Hz AC power

We always made 400Hz from 60Hz using a motor/generator pair. I assume they make them for going the other way as well.

To use a motor generator set would be rather futile why not drive the generator of said set directly from the engine that was proposed to drive the 400 Hz unit !!!

Speed = freq ... Just slow that gen set WAY down ...

like already mentioned motor - generator is best option but at efficiency cost, change the only generator for 60Hz supply if you like , AC-DC-AC phase converters you already opted out

Perhaps drive it at 60/400 times the speed, and then adjust field strength to get the right voltage. (You may need to rewind things however.)

If You are having DG set to produce power at 400 Hz,you may reduce the speed to have 60 hz.since f=PN/120, where f-Frequency,N-RPM,P-No of poles.

But if the alternator is designed to develop the required voltage at 400Hz,it may not develop same voltage at reduced RPM.

With same primemover you can couple differant alternators to have differant frequencies.

If you simply slow down the generator, you will probably fry the generator windings and the voltage regulator. The AC impedance (inductive reactance) of any winding is directly proportional to the frequency (X_L = 2∏fL). At 60 Hz you have reduced the frequency to 15% of rated, and reduced the winding impedance by a similar amount. For a given voltage, the current will increase by over 650%! Since the basic limitation of generator capacity is the ability of the windings to remove the heat generated by the current, the generator itself could work, if you limited load to about 15% of the rated output.

The voltage regulator would simply not work. The voltage output is directly proportional to the both field strength and the speed. Reducing speed by a factor of 6.66 means that the regulator output must increase by the same ratio to generate rated voltage. I don't think there's a regulator design in the world built for that kind of abuse.

Unfortunately, there really is no easy and inexpensive way to do this. My best suggestion would be to see if you can find a surplus 400 HZ rectifier. Most military navigation and weapons electronics have these, and you might be able to find an obsolete avionics or nav package for a reasonable price. Once you've got DC, all you need is an inverter, like a big UPS. Again, you might find one of these on the surplus market.

I do not think it is economical to change the 400 hz MG to make it do something it was NOT designed to do.

Trade or sell your unit for what you need and reduce your total cost for the long run.

Probably you need a AC-DC-AC inverter. And 60KW is huge.

By slowing the generator speed down you also will severley alter the prime movers HP curve. E Bay that mf'er!

Is your unit diesel powered or does it have an electric motor? What is your price if you want to sell.

Tks.

Gary Collins

gcollins4@comcast.net