Induction motors can be feed from one frequency converter in the common AC
link.
High supply voltage is possible leading to a reduction of the diameter of
the cabling in the textile machine.
The motor needs no maintenance.
The main disadvantage of the induction motor is its need of reactive power which leads to an oversized frequency inverter. Because of the rotor slip each spindle needs its own speed sensor. Different loads of the spindles lead to different speeds. The slip losses reduce the degree of efficiency. Because of the reactive current the motor current is not proportional to the spindle torque - measuring the shaft torque via the motor current is therefore quite complex.
At least the production of the induction motor is quite expensive because of the small air gap, the rotor lamination and the aluminum cage.