AC brushless permanent magnet servo motors will not run off of mains three phase directly, they require commutation.
The drives convert the incoming AC to DC and then manufacture electronically the three phases and receive commutation signals from the motor.
If you are concerned about the AC power to the drives, it does not matter if the 3 phase is delta or star (Wye), as long as it is the right voltage.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.