General recommendations on How to Choose Appropriate Stepper Motor

A stepper motor is an electromechanical device it converts electrical power into mechanical power. Also it is a brushless, synchronous electric motor that can divide a full rotation into an expansive number of steps. The motor’s position can be controlled accurately without any feedback mechanism, as long as the motor is carefully sized to the application. Stepper motors are similar to switched reluctance motors.

General recommendations on How to Choose Appropriate Stepper Motor


Unless you will be using external stepper motor drivers, choose motors with rated current of at least 1.2A, and at most 2.0A for the Duet 0.6 and Duet 0.8.5, or 3A for the Duet 2.

Plan to run each stepper motor at between 50% and 85% of its rated current.
Size: Nema 17 is the most popular size used in 3D printers. Nema 14 is an alternative in a highly-geared extruder. Use Nema 23 motors if you cannot get sufficient torque from long Nema 17 motors.

Avoid motors with rated voltage (or product of rated current and phase resistance) > 4V or inductance > 4mH.

Choose 0.9deg/step motors where you want extra positioning accuracy, e.g. for the tower motors of a delta printer. Otherwise choose 1.8deg/step motors.

If you use any 0.9deg step motors, or high torque motors, use 24V power so that you will be able to maintain torque at higher speeds.

If using a highly-geared extruder (for example, an extruder that uses a flexible drive cable to transmit the torque from the motor to a worm reduction gear), use a short low-inductance 1.8deg step motor to drive it.

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