There are 3 main reasons why people use VFD:
1. VFD can help users to achieve high precise speed control, torque control and tension control, so the productivity can be enhanced.
2. Most of the VFDs have been designed with motor soft starting function, so the mechanical wear could be reduced.
3. By using a VFD, the energy consumption can be cut down about 60%, so a lot energy cost could be saved.
About VFD drive choices, I recommend the Veichi VFDs, Simens VFDs, Hitachi VFDs.