Frequency Converter, also called a Frequency Changer, convert 50Hz and 60Hz to 400Hz power.  This is done either by means of a double conversion Static Frequency Converter or by using a motor generator set called a Rotary Frequency Converter.

Frequency converters are machines that convert power from one frequency to another frequency.  Either by means of a double conversion Static Frequency Converters or by using a motor generator set called a Rotary Frequency Converter.

In the double conversion method, the Rectifier converts AC into DC and the Inverter converts DC back into AC.  In a Motor Generator Set, this is completed by either changing the rotational speed of the generator in the versions with belts & sheaves or the gear box and by means of motors and generators with a different number of poles operating to achieve the same result of producing the desired output frequency.