Answer: A stepper motor which is turned by a load produces a back EMF voltage on the driver. Higher speeds will create larger voltage ranges. In the event the rotational speed receives excessively higher, this voltage could injury the driver. This is especially dangerous if the motor is back again-driven https://originofficehhe.eedblog.com/40297106/understanding-the-differences-between-pm-and-vr-stepper-motor-types