Classification of Stepper Motors

Posted by

power

On 02/01/2025

Stepper motors can be classified based on their construction and operational principles. Below are the primary types of stepper motors:

Construction: Typically, these motors are two-phase (bipolar or unipolar), where the rotor is made of soft iron and does not have permanent magnets.
Torque and Size: They generally offer smaller torque and size compared to other types of stepper motors.
Step Angle: The step angle is usually large, typically 7.5° or 1.5°.
Application: Due to their low cost and simple design, reluctance stepper motors are used in applications where precision is less critical, but cost and size are significant factors.

Construction: These motors typically have three phases and use a permanent magnet in the rotor.
Torque: Permanent magnet stepper motors can deliver higher torque compared to reluctance motors.
Step Angle: The step angle is generally 1.5°.
Drawbacks: While they offer higher torque, PM stepper motors are known for producing significant noise and vibration during operation.
Decline in Use: In developed countries like the U.S. and Europe, these motors were largely phased out in the 1980s due to their noise and vibration issues, being replaced by more efficient alternatives.

Construction: Hybrid stepper motors combine the advantages of both permanent magnet and reluctance motors.
Phase Variations: They can come in two-phase, three-phase, and five-phase versions.
- Two-Phase Hybrid Stepper Motors: These motors typically have a step angle of 1.8°.
- Five-Phase Hybrid Stepper Motors: These motors have a finer step angle, typically 0.72°.
Precision: As the number of phases (electrically powered windings) increases, the step angle decreases, resulting in higher precision and smoother motion.
Most Common Type: Hybrid stepper motors are the most widely used type today, offering a good balance of torque, precision, and noise reduction.

The choice of stepper motor type depends on factors such as required torque, precision, noise tolerance, and application environment.