831eb72a_es_content_from_Machine_Design__Induction_motor
[0] ACCURACY [PMAC] Without feedback, can be difficult to locate and position to the pinpoint accuracy of servomotors [Servomotor] Closed-loop servomotor operation utilizes feedback for speed accuracy to ±0.001% of base speed [Induction motor] 
Flux vector and field-oriented control allows for some of accuracy of servos
The difference between AC induction, permanent magnet, and servomotor technologies | Motors/Drives content from Machine Design
Induction motor