AC servo motor to replace a 3 phase induction motor on a mill spindle.

[rnr107]

Hi all,
I am trying to replace the spindle motor on my mill (a 3 phase motor running from an inverter) with an AC servo motor.
Now, the original motor is a 3 phase (delta 240V) / 0.37KW / 4 poles / 1400RPM
The servo I have is: AC / 0.75KW / 3000RPM

The servo is physically a lot smaller but the power rating is a lot more... That get me a bit confused...
How is it possible to get twice more power in about a 1/3 of the size ?

Is this servo big enough to replace the original motor or would it struggle ?

Ta,
RNR