In today market there are so many industrial sewing machine motors so call “Energy Saving Servo Motor”, “Power Saving Servo Motor” or “Brushless Dc Servomotor”. These sewing machine motors are not REAL servo motor.

Hightex HVP-70 is the REAL servo motor for heavy duty industrial sewing machine: Powerful + Quiet + Accurate Speed Control!

This servo motor can drive 733 machine easily: the heaviest industrial sewing machine with 32 mm presser foot lift and 11 KGS, 345 mm (Diameter) large flywheel......

http://www.cowboysew.com/product909.htm