Choosing a motor for an OEM machine often starts with a simple question: what type of motor fits the application?
This FAQ answers common questions about stepper motors, BLDC motors, servo motors, and motor drivers, from basic operating principles to motor selection, torque, speed, feedback, and typical applications.
If you are mainly evaluating a stepper motor, start with the questions below about how stepper motors work, where they are used, how to choose the right size, and when to use open-loop or closed-loop control.
A. Stepper Motor Basics
1. What Is a Stepper Motor?
A stepper motor is an electric motor designed to move in controlled, incremental steps. Instead of rotating continuously like a typical DC motor, it moves the rotor to defined positions as electrical pulses are sent to the motor phases. This makes stepper motors useful for applications that need predictable positioning, indexing, or repeatable motion. Most industrial stepper motors are hybrid designs, combining a toothed rotor with permanent magnets to provide a small step angle and useful holding torque.
2. What Are Stepper Motors Used For?
Stepper motors are used for controlled positioning, repeatable movement, indexing, and other motion-control tasks. Common applications include CNC equipment, 3D printers, automation machinery, laboratory equipment, medical instruments, camera mechanisms, robotics, and linear positioning systems. They are particularly useful when the controller needs to command a motor to move a known number of steps. The right motor still depends on the load, required torque, speed, acceleration, duty cycle, and available installation space.
3. What Is a Stepper Motor Used For?
A stepper motor is used when a machine needs controlled rotary motion rather than simply continuous motor rotation. A controller can send a defined number of pulses to command a specific amount of movement, which makes steppers practical for positioning and indexing. They are commonly found in CNC machines, printers, automation equipment, medical instruments, camera systems, robotics, and other equipment where repeatable motion matters. For each application, motor torque, speed, acceleration, and load conditions need to be considered together.
4. What Is the Use of a Stepper Motor?
The main use of a stepper motor is controlled and repeatable motion. It can move a mechanism by a defined number of steps, making it suitable for positioning, feeding, indexing, and rotary-to-linear motion systems. For example, a stepper motor can drive a lead screw to move a machine axis or control the position of a camera mechanism. Its usefulness comes from the combination of simple pulse-based control, repeatable movement, and available torque across a wide range of motor sizes.
5. Is a Stepping Motor the Same as a Stepper Motor?
Yes. “Stepping motor” and “stepper motor” normally refer to the same type of motor. “Stepper motor” is the more common term in English technical and commercial content, while “stepping motor” is also widely used, particularly in engineering documentation and some regions. Both describe a motor that converts electrical control pulses into incremental rotational movement. For search purposes, these terms can be treated as close semantic variants rather than completely different motor types.
6. Is a Step Motor the Same as a Stepper Motor?
In most engineering and product contexts, yes. “Step motor” is a shortened form of “stepper motor” and usually describes the same motor technology. The terms may appear differently in search queries, product documentation, or supplier catalogs, but the basic operating principle is the same: the motor moves in discrete angular steps in response to electrical excitation of its phases. For technical specifications and product searches, “stepper motor” is generally the clearest term to use.
7. What Are the Main Types of Stepper Motors?
The three traditional types of stepper motors are permanent magnet, variable reluctance, and hybrid stepper motors. Permanent-magnet designs use a magnetized rotor, while variable-reluctance motors use a toothed rotor without permanent magnets. Hybrid stepper motors combine features of both designs and are widely used where fine step resolution and useful holding torque are required. For industrial and OEM applications, hybrid stepper motors are the type most commonly encountered in modern motion-control equipment.
B. How Stepper Motors Work
8. How Does a Stepper Motor Work?
A stepper motor works by energizing its winding phases in a controlled sequence. The magnetic field created by the energized coils pulls the rotor toward the commanded position. Each change in the electrical sequence produces another incremental movement. A driver receives control signals from the motion controller and regulates current through the motor windings. With a typical 1.8° stepper motor, one full revolution requires 200 full steps, while microstepping can divide those electrical steps into smaller command increments.
9. What Is a Hybrid Stepper Motor?
A hybrid stepper motor combines the magnetic structure of a permanent-magnet motor with a toothed rotor and stator structure. This design provides a small step angle, useful holding torque, and predictable incremental movement. A common industrial hybrid stepper motor has a 1.8° full-step angle, although other configurations are available. Apexwell's current stepper motor range includes hybrid designs across compact and larger frame sizes, including NEMA 8, NEMA 11, NEMA 14, NEMA 23, and NEMA 34 products.
10. What Is Microstepping in a Stepper Motor?
Microstepping divides a motor's normal full steps into smaller electrical increments. For example, a 1.8° stepper motor has 200 full steps per revolution, while 1/16 microstepping commands 3,200 microsteps per revolution. Microstepping can make motion smoother and reduce vibration and audible resonance, especially at lower speeds. It should not be treated as a simple way to multiply mechanical positioning accuracy, because actual accuracy also depends on motor construction, load, control, mechanical transmission, and system feedback.
11. Does a Stepper Motor Need a Driver?
Yes, a conventional stepper motor normally requires a suitable driver between the controller and the motor. The driver receives control signals such as step and direction and regulates the current flowing through the motor windings. It also determines important operating characteristics such as current control, microstepping, and in some systems protection or feedback functions. Choosing the driver should be based on the motor's rated phase current, supply voltage, control interface, and application requirements rather than simply choosing the highest-current driver available.
12. What Does a Stepper Motor Driver Do?
A stepper motor driver converts commands from the controller into the controlled electrical current sequence required by the motor windings. Modern drivers normally regulate winding current electronically rather than simply applying a fixed voltage. The driver therefore has a major effect on motor smoothness, noise, acceleration performance, and available speed range. When selecting a driver, check the motor's phase current, supply voltage, desired microstepping resolution, control interface, and whether the system requires functions such as stall detection or encoder feedback.
C. Stepper Motor Selection
13. How Do I Choose a Stepper Motor?
Choose a stepper motor by starting with the application's actual load and motion requirements rather than selecting a NEMA size first. Check the required torque, target speed, acceleration, duty cycle, power supply, mounting space, shaft dimensions, and control method. Then compare the motor's torque-speed curve with the real operating point. If occasional step loss would cause unacceptable scrap or downtime, consider a closed-loop stepper motor. For OEM designs, mechanical interfaces such as shaft dimensions, connectors, and mounting pattern should also be checked before final selection.
14. How Much Torque Does a Stepper Motor Need?
The required stepper motor torque depends on the actual load, friction, acceleration, transmission, and operating speed. A practical calculation should include load torque and acceleration torque, followed by an appropriate safety margin. Holding torque alone is not enough for a moving application because usable motor torque decreases as speed increases. For a lead-screw system, for example, the screw lead, mechanical efficiency, load force, and acceleration all affect the required motor torque. Always check the motor's torque-speed curve at the intended operating speed.
15. How Fast Can a Stepper Motor Run?
There is no single maximum speed for all stepper motors. The usable speed depends on motor size, winding characteristics, supply voltage, driver settings, load, acceleration, and the required torque at speed. A stepper motor generally produces less usable torque as speed increases, so a motor that has sufficient holding torque at zero speed may not have enough torque at the application's operating speed. For this reason, engineers should evaluate the manufacturer's torque-speed curve rather than selecting a motor based only on its rated holding torque.
16. What Is a NEMA Stepper Motor?
A NEMA stepper motor is a stepper motor built around a standardized mounting frame size commonly identified by a NEMA number. The NEMA designation mainly describes the motor's mounting dimensions; it does not by itself tell you the motor's torque, speed, current, or overall performance. Two motors with the same NEMA size can have different body lengths, winding specifications, torque ratings, and electrical characteristics. Therefore, NEMA size should be used as one part of motor selection, not as a substitute for checking the complete datasheet.
17. What Is the Difference Between NEMA 8, NEMA 23, and NEMA 34 Stepper Motors?
The main difference is the motor's frame size and the range of mechanical and torque options typically available within that frame. Smaller frames such as NEMA 8 are useful where installation space is limited, while NEMA 23 and NEMA 34 provide larger physical platforms for applications requiring more torque. Frame size alone does not determine performance, however. Body length, winding, current, rotor inertia, speed, and the actual load must all be considered. Apexwell currently offers stepper motor series across NEMA 8, NEMA 23, and NEMA 34, among other frame sizes.
18. What Voltage and Current Does a Stepper Motor Need?
The required voltage and current depend on the specific motor winding and driver. The motor's rated phase current is particularly important because the driver should be configured to supply the correct current rather than simply its maximum available output. Supply voltage also affects high-speed performance because a higher voltage can help the driver establish winding current more quickly as step rate increases. Always use the motor datasheet and driver specifications together when setting current and selecting the power supply.
19. Can a Stepper Motor Run Continuously?
Yes. A stepper motor can run continuously when it is correctly sized for the load, speed, duty cycle, temperature, and driver. However, continuous operation should not be evaluated only by whether the motor can rotate. The required torque at operating speed, winding current, temperature rise, acceleration profile, and mechanical load all matter. For applications involving long operating periods or higher speeds, the motor's torque-speed characteristics and thermal limits should be checked under the actual working conditions.
D. Open Loop, Closed Loop and Motor Comparisons
20. Can a Stepper Motor Lose Steps?
Yes. An open-loop stepper motor can lose steps if the commanded motion exceeds the motor's available torque under the actual operating conditions. This can happen during excessive acceleration, sudden load changes, insufficient torque, resonance, or operation outside the motor's usable speed range. Because an open-loop system normally assumes the rotor follows the commanded pulses, it may not detect the error. Correct motor sizing, acceleration control, and an adequate torque margin reduce the risk. A closed-loop stepper adds encoder feedback so the system can monitor actual rotor position.
21. What Is an Open-Loop Stepper Motor?
An open-loop stepper motor system commands movement without directly measuring the rotor's actual position. The controller sends pulses to the driver and assumes that the motor follows those commands. This approach keeps the system relatively simple and works well when the load is predictable and the motor has enough torque margin. Its limitation is that a missed step may not be detected. For applications where occasional positioning errors would create significant downtime, scrap, or other problems, a closed-loop stepper motor may be worth considering.
22. What Is a Closed-Loop Stepper Motor?
A closed-loop stepper motor adds an encoder to the motor system so the controller or driver can compare commanded motion with actual rotor position. If the motor falls behind the commanded position, the control system can detect the error and respond according to its control strategy. This makes closed-loop steppers useful for applications where open-loop step loss is difficult to tolerate but full servo performance is not required. Apexwell's current range includes closed-loop hybrid stepper motors such as the NEMA 8 AW20HS and NEMA 23 AW57HS series.
23. What Is the Difference Between Open-Loop and Closed-Loop Stepper Motors?
The main difference is feedback. An open-loop stepper system commands the motor and assumes it reaches the commanded position, while a closed-loop system uses encoder feedback to monitor actual rotor movement. Open-loop systems are simpler and can be a good fit for predictable loads with sufficient torque margin. Closed-loop systems add feedback and are useful when missed steps need to be detected or corrected. The choice should therefore be based on the application's load variation, positioning requirements, cost, speed, and consequences of a positioning error.
24. What Is the Difference Between a Stepper Motor and a Servo Motor?
Stepper motors and servo motors both provide controlled motion, but they use different control approaches and are suited to different operating conditions. A conventional stepper system can achieve predictable positioning through commanded pulses without an encoder, while a servo system normally uses continuous feedback to control position, speed, and torque. Steppers are often practical for lower- to medium-speed positioning where simplicity matters. Servo motors become more relevant when high speed, dynamic response, and continuous closed-loop control are central requirements. The right choice depends on the complete motion profile rather than one specification.
25. What Is the Difference Between a Stepper Motor and a BLDC Motor?
A stepper motor is primarily designed for controlled incremental positioning, while a BLDC motor is generally used for efficient continuous rotation and speed control. A stepper can move to defined positions through controlled phase excitation and is often used in positioning systems. A BLDC motor typically operates as a continuously rotating motor and may use Hall sensors, an encoder, or other feedback depending on the application. The better choice depends on whether the system's main requirement is positioning, continuous speed, efficiency, torque, or a combination of these factors.
E. Stepper Motor Applications
26. Where Are Stepper Motors Commonly Used?
Stepper motors are commonly used in equipment that needs controlled, repeatable movement. Typical applications include CNC machines, 3D printers, automation equipment, laboratory instruments, medical positioning systems, camera and lens mechanisms, robotic mechanisms, and linear stages. The motor can be connected directly to a rotary load or combined with components such as lead screws, pulleys, or gearboxes to create linear or geared motion. The appropriate stepper motor depends on the application's torque, speed, accuracy, duty cycle, and installation constraints.
27. Are Stepper Motors Suitable for CNC and Automation Equipment?
Yes. Stepper motors are widely used in CNC and automation equipment where controlled positioning and repeatable movement are required. They can drive rotary axes, lead screws, indexing mechanisms, feeders, and other positioning systems. For lighter or predictable loads, an open-loop stepper may be sufficient. If a missed step could affect machining accuracy, production quality, or equipment downtime, a closed-loop stepper can provide encoder feedback. Apexwell's NEMA 23 AW57HS closed-loop series, for example, is specified for CNC routers, mills, positioning stages, packaging equipment, and robotics applications.
F. OEM & Custom Stepper Motor
28. Can a Stepper Motor Be Customized for an OEM Application?
Yes. Stepper motors can be customized when the standard motor does not match the equipment's mechanical or electrical requirements. Depending on the motor series, customization can include winding parameters, shaft dimensions, mounting configuration, lead wires, connectors, encoders, and other mechanical features. The important point is to define the application first: required torque, speed, voltage, installation space, shaft interface, feedback, and control method should be understood before specifying the motor. Apexwell supports application-specific motor configurations for OEM equipment based on these requirements.
29. How Do I Choose a Stepper Motor for an OEM Project?
For an OEM project, start with the machine rather than the motor catalog. Define the required torque, operating speed, acceleration, duty cycle, supply voltage, mounting space, shaft dimensions, control interface, and whether encoder feedback is needed. Then compare those requirements with the motor's torque-speed curve and mechanical specifications. If the standard motor does not fit, an OEM supplier may be able to adjust the winding, shaft, mounting, connector, or feedback configuration. Providing these details early usually makes motor selection faster and reduces redesign later.
Need Help Choosing a Motor?
If you already know the basic requirements but are not sure which motor fits your equipment, send us the key application details.
Useful information includes required torque, operating speed, supply voltage, installation space, shaft dimensions, duty cycle, and whether encoder feedback is required. Apexwell can help evaluate standard motor options or discuss application-specific configurations for OEM equipment.
