Glossary · Motion control and drives
Stepper motor
Also known as: Stepping motor, Step motor
German: Schrittmotor
In motion control, a stepper motor is a motor that rotates in discrete angular steps when its windings are energized in sequence by a driver, so position can be controlled by counting steps without feedback.
- Motion control
In one sentence
A stepper motor turns in discrete steps as its windings are energized in sequence, so position can be set by counting steps.
Example
A format adjustment spindle is driven by a stepper motor that moves a guide rail to the position stored in the recipe.
How it applies
- Engineering: Stepper motors are simple and inexpensive and hold torque at standstill when energized. Typical step angles are 1.8° or 0.9°, refined by microstepping. Torque drops at higher speeds.
- Commissioning: Current and microstep settings in the driver must match the motor; resonance at certain speeds may need damping.
- Operation: In open loop, overload causes lost steps, and the controller doesn't notice. Closed-loop steppers with encoders detect this.
- Documentation: Explain that after a collision or power loss the position may be wrong and homing is required. Describe symptoms of lost steps in the troubleshooting section.
Stepper motor vs. servo motor
A stepper positions by counting steps, usually without feedback. A Servo motor always uses feedback and corrects deviations, offering higher speed and dynamics.