How to Select a Stepper Motor: 6 Essential Tips for Best Choice
Knowing how to select a stepper motor correctly is vital for achieving precise and efficient automation. Stepper motors are widely used in mechatronics and control systems, and selecting the right motor involves understanding torque, speed, motor types, accuracy, and driver requirements. This guide walks you through 6 essential tips to choose the best stepper motor for your application.
1. Understand Stepper Motor Types
There are three main types of stepper motors based on rotor construction:
Permanent Magnet (PM): Features a stator with claw poles and a permanent magnet rotor, offering larger step angles (7.5°–15°) but smaller torque and lower cost.
Hybrid (HB): Combines features of PM and VR motors, with small step angles (typically 1.8°), high torque, and fast response but higher price.
Variable Reluctance (VR): No permanent magnets, step angles vary from 1.8° to 15°, medium torque, and generally less efficient.
Choosing the motor type depends on your application's torque, speed, and budget requirements.
| PM | HB | VR | |
| Step Angle | 7.5°∼15°More | 1.8° More | 1.8°∼15° |
| Torque | Small | Large | Medium to Large |
| Time constant | Small to Medium | Small | Large |
| Price | Cheap | Expensive | Expensive |
2. Calculate Required Torque Accurately
Torque is critical when selecting a stepper motor. Ensure the motor’s static torque output exceeds load torque, accounting for inertial and frictional components. Consider a safety factor of 1.3 to 2 to guarantee reliable operation. Remember, inertial loads dominate during acceleration, while frictional loads affect constant speed operation.
3. Determine the Appropriate Motor Speed
Stepper motors operate differently at low and high speeds. For low-speed applications, choose motors with small step angles and consider three-phase motors to minimize vibration and resonance. High-speed applications require motors with lower coil inductance and higher phase current capacity. Selecting a suitable driver with high supply voltage can improve performance at elevated speeds.
4. Select Suitable Motor Mounting and Size
Common frame sizes range from NEMA8 (20×20mm) to NEMA42 (110×110mm). Larger frames generally provide higher torque. If installation space is limited, consider advanced options like MOONS' PowerPlus hybrid stepper motors, which increase torque by 25%–40% through optimized magnetic design without raising voltage or current.
5. Assess Positioning Accuracy Needs
High-precision stepper motors feature smaller step angles, reduced cogging torque, and strong transient response. More motor phases mean higher precision but increased complexity. Typical options include two-phase motors (1.8°, 0.9°), three-phase (1.2°), and five-phase motors (0.72°, 0.36°). For noise-sensitive applications, micro-stepping further smooths motion and reduces vibration.
6. Choose the Right Driver Based on Motor Specs
The driver must match motor current, subdivision (micro-stepping), and supply voltage requirements. Using intelligent selection tools like HDBMOTOR' SEARCH ROBOT can simplify this process, offering torque and temperature rise analysis across operating frequencies to optimize your choice.
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