Good eye Screwit! Should be 3 stage on 50 hz, due to the lower rpm of the motor.
The 2 stage CTV's can be applied on 400-415/3/50 power supply when using the AFD to convert to 460/3/60 supply to the motor. Just trying to figure out if this is close to home or not and how to help the OP. Can't recall RTHD & CVHF combination on a data centre in a tropical location down here so figuring it is somewhere else.