for 200 amps load can we able to generate 400 hertz supply directly from the alternator output? if it is possible how the design factors changed from 50 hertz supply? is it safe and economical to generate 400 hertz or by using converters is safe for higher ratings loads............................................................... supply voltage at 200 volts ph -ph

Boby,

I do know that some of the micro turbine systems use high frequency AC alternators which are rectified and pushed through an inverter drive so it is clearly possible. My imediate thought would be limitations on the magnetising elements I know at low frequencies transformers get upset due to the B-H characteristics of the core material. You would obviously need a prime mover / gear box combination that provided a regulated rotational speed. The micro turbines are more like turbo chargers and ther is often a single air bearing so there is minimal torque or out of balance loads. I suspect you would have more success obtaining some sort of electronic device to invert a DC pre rectified DC supply.
Out of curiosity; Why do you want to do this?

because aircrafts need 400 hz supply...... after landing they require power at 400 hz from ground side becz aircraftengine stopped

Hello boby

To increase the frequency output of an alternator, you have to increase the speed that it is rotating at.
To convert a 50Hz alternator to 400Hz, you would need to increase the speed by a factor of 8. It is highly unlikely that any 50Hz alternator would survive at this speed, so your options are to use a special alternator (aircraft style), and some form of high speed engine such as a turbine, or to use some sort of inverter to generate the high frequency output.
I suspect that the latter would be very expensive.

Good luck and keep us informed.
Best regards,

Boby,

Further to Marke's comments. The micro turbines I mentioned earlier were developed from aircraft technology. A company called Allied SIgnal (who I think are american based in Albequerque) developed a micro turbine directly from an aircraft unit and this was equipped with a high speed alternator. This technology has taken off (pardon the pun) recently due to carbon paranoia as micro CHP a sort of hybrid replacement for domestic combination boilers. I suspect if you google micro turbine you get get a starting point.