A stepper motor is a type of electric motor designed to convert digital electrical signals into precise angular mechanical movements. Unlike conventional motors that rotate continuously, a stepper motor operates in fixed increments known as "steps."
Each electrical pulse received by the motor corresponds to a specific angular movement, usually measured in degrees. This feature allows for accurate control of positioning, speed, and acceleration—often eliminating the need for external sensors for position feedback.
The stepper motor is widely used in applications that require precise control of incremental movements. It is essential in fields such as industrial automation, robotics, and electronics, where precision is key to ensuring efficiency and quality.
Examples of use include synchronization of industrial processes, movement of robotic arms, valve control, cutting machines, and 3D printing. Stepper motors offer great cost-effectiveness, serving as an efficient and reliable alternative to servo motors in applications that don’t require real-time feedback.
Stepper motors offer several advantages, such as high torque at low speeds, rapid starts, and precise stops. Their high positioning accuracy and easy control make them ideal for applications that demand exact movements.
Additionally, the absence of brushes increases mechanical durability, making them reliable and low-maintenance. Their ability to quickly change rotation direction is another benefit, offering flexibility across a wide range of industrial applications.
Stepper motors enable precise positioning operations, so they are used when high accuracy is required for demanding positioning tasks. They consist of a stationary stator and a rotor rotating within it, which is driven by torque generated by differently aligned magnetic fields in the stator and rotor. The rotor always rotates in such a way that the greatest possible magnetic flux is created. Stepper motors are primarily used in factory automation, but are also being used more and more in mechanical and plant engineering.
Very high torque at a low rotational speed is characteristic of stepper motors. On the one hand, this enables a quick start, and on the other hand – thanks to the high holding torque – the ability to easily stop the application. The direction of rotation can also be changed quickly at any time. Other fundamental advantages of stepping motors are the high level of accuracy that is achieved with their use and the simple control of the respective rotor position. In addition, there are no brushes installed in stepper motors, which contributes significantly to the high mechanical durability of the application.
There are basically three different types of stepper motors: the reluctance stepper motor, the permanent magnet stepper motor and the hybrid stepper motor. The latter combines the properties of reluctance and permanent magnet stepper motors and is therefore the most efficient of the three variants. Hybrid stepper motors have a stator with multi-toothed stator poles and a rotor consisting of up to 200 rotor teeth, which can move in step angles of 1.8° each. Hybrid stepper motors have a high static and dynamic torque and a very high stepping speed and are therefore used in numerous applications, including PC drives and printers. The main areas of application for hybrid stepper motors in industry are machine tools and handling machines.
Festo relies on hybrid technology in the further development and production of stepper motors. The EMMS-ST stepper motor is part of our core range and is ideally suited for simple positioning applications. EMMS-ST enables small increments with high driving torques, has optimized connection technology and is available in four sizes with flange dimensions of 28, 42, 57 and 87. It is also optionally available with a holding brake.