How To Choose The Size Of A Stepper Motor

 Confused about how to choose the size of a stepper motor? Go through this list and find out the answer to all your questions. Another alternative is to let SMooth Motors help you pick your requirements. 

January 11, 2024

Choosing the right stepper motor size is crucial to motion control system design and implementation. Robotics and 3D printing are two of several disciplines that benefit from stepper motor reliability and precision. To know how to choose the size of a stepper motor, you must first identify your application's unique needs and then compare them to the motor's specifications.

Stepper Motor Types

Hollow shaft and two, three, or five-phase stepper motors are offered. Torque, accuracy, and affordability are three areas where each kind excels. Consider 3-phase stepper motors and 2-phase stepper motors, which provide a happy medium between price and performance, and 5-phase motors, which offer more torque and more consistent functioning. Because of their exceptional integration capabilities, hollow shaft motors have many potential uses.

2 Phase Hybrid Stepper Motors

Size and Torque

A stepper motor's torque is proportional to its size. For moving bigger weights, more torque, which is often provided by larger motors, is necessary. Bigger isn't always better, however. Excessive power consumption and extra expenses might result from too big motors. To determine the necessary torque, one must consider the load, the speed, and the properties of the mechanical system.

Resolution and Precision

Because of its accuracy, stepper motors are preferred. The resolution, which is usually expressed in steps per revolution, defines how precisely the motor can move. Motors with a higher resolution allow for more accurate control, essential in fields such as robotics and computer numerical control (CNC) machining.

Power Requirements

The size and needs of the application determine the power requirements of a stepper motor. Before purchasing a motor, ensure it is compatible with your power source and control system by researching its voltage and current requirements.

Approach to Driving

The driving technique should also be taken into account since it has a significant impact on the performance of the stepper motor. Standard driving techniques include bipolar and unipolar driving, continuous voltage and current driving. Unipolar driving circuits employ four power tubes and have a single-direction coil current flow, in contrast to bipolar and unipolar driving circuits. Compared to unipolar driving circuits, bipolar driving circuits need eight power tubes.

Plus, the coil's forward and reverse currents conduct in opposite directions and flow through it in a reversal fashion. However, a short circuit in the power source and a powerful current will result from simultaneous conduction in a short period. An additional circuit to avoid short circuits is, hence, required. An increase in complexity from the unipolar to the bipolar driving circuit is evident. In most cases, unipolar driving is better suited for high-speed drives, whereas bipolar driving is more appropriate for low-speed and high-torque loads.

Application-Specific Considerations

There could be specific needs for certain applications when it comes to how to choose the size of a stepper motor. Industrial automation may place a higher value on torque and durability than a 3D printer, which prioritizes small size and precise control. You must first determine your application's unique requirements to choose the correct motor.

Reliability and Durability

Continuously running motors or motors subjected to harsh conditions raise serious concerns about dependability and durability. To avoid breakdowns and maximize performance over time, get a motor from a trusted brand with experience in your field.

Customizing Choices

Commercially available motors may fall short of your expectations on occasion. Try to find manufacturers that let you personalize your purchase in these instances. Some examples of such arrangements include integrated controllers, modified shafts, or specialized windings.

Operating Voltage

The machine's operating conditions determine the driving voltage, which is the driver's input voltage. The voltage may be 12V–48V, 24V–220V, or 50V–60V. A stepper motor with a higher voltage will operate better, especially at high speeds.

Current Driving

The driving current of a stepper motor is the current flowing through its single-phase winding from end to end. The driving current is not an absolute minimum; the stepper motor can operate with currents much higher or lower than this.

Bottom Line

Knowing the unique requirements of your application and the features of various motor types is essential when learning how to choose the size of a stepper motor. You may choose a motor that satisfies but also improves your system's performance by considering things like resolution, torque, power demands, and application-specific requirements. Keep in mind that the biggest or most costly motor isn't always the greatest option; what matters is selecting the one that works best for your particular task.


Let Smooth Motor handle your worries regarding Stepper Motors. As a leading stepper motors manufacturer, we know how to choose the size of a stepper motor. Our experts can guide you through the process. Contact us, and let's get started!

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