What term describes the maximum torque a stepper motor can withstand without moving when the stator is de-energized?

• A. Holding torque
• B. Detent torque
• C. Static torque
• D. Locking torque

Answer: (B)

Detent torque is the resistance to rotation a stepper motor exhibits when its windings are not energized. In a hybrid stepper, permanent magnets and the geometry of the stator teeth create a small magnetic attraction between rotor and stator, so the rotor can stay in a commanded position even with no power. This unpowered torque is the maximum torque the motor can resist before the rotor moves when the stator is de-energized.

Holding torque, by contrast, requires energized windings to resist motion, so it’s not the right term for the unpowered condition. Static torque and locking torque aren’t the standard terms used to describe this unpowered, positional hold in stepper motors, whereas detent torque precisely captures the unpowered holding effect caused by the magnetic interaction inside the motor.