Is it better to control motor speed or torque?

For pacer sections, motors are speed controlled. In open-loop tension control, motors are used in either speed (or draw) or torque control depending on what is best for the process. In closed-loop tension control, there is a growing debate on the best approach.

For many years, I have been taught that most multi-zone processes with closed-loop tension control adjust motor speed, trimming +/- 5-10 percent of the pacer’s speed reference. More recently, I have heard good cases made that new drive technology works better in torque control mode. The central argument is that motors are torque generators. Anytime you use a motor in speed mode, you are adding a level of complexity.