In the Royal Dutch Airforce we used 115 V ac delta at 60 Hz and 400 Hz.
This was generated by diesel gensets or a 380/660 star delta rotary converter from the POCO mains.

The other Voltage was 416 Volts at 400 Hz for 3 Ø motors and hi power equipment.

So probably its the same as 120 / 450 Volts system discussed here for military applications.

Regards

Raymond

The product of rotation, excitation and flux produces electricty.