Stepper motors – find manufacturers and suppliers

Stepper motors are a special type of electric motor that are characterized by precise motion control and exact positioning.

They are often used in applications where accuracy and repeatability are crucial.

Below you will find the mode of operation, the control system and an overview of the types and application areas of stepper motors as well as their advantages and disadvantages.

How stepper motors work:

Stepper motors move in fixed angular steps that are controlled by electrical pulses. Each pulse moves the rotor by a certain angle.
In this context, the terms full step, half step and micro step are used for stepper motors. For example, a 1.8° full-step motor has 200 individual positions for a complete 360° rotation. 360:200=1.8. The 0.9° half-step motor achieves 400 individual positions during a 360° rotation. 360:400=0.9. Micro stepper motors can achieve 1/5, 1/10, 1/16, 1/32, 1/125 and 1/250 of a full step using sophisticated motor controls.

Control of stepper motors:

Stepper motors require special controllers, usually called stepper motor controllers or drivers. These generate the electrical pulses required to control the movement of the motors and can be either analog or digital.
The step resolution can be increased through microstepping, resulting in smoother movement and greater accuracy.
In some cases, a feedback loop (closed loop) is used to ensure that the motor does not lose steps and maintains the exact position.

Types of stepper motors:

1. Reluctance stepper motor:
   In the reluctance stepper motor, the rotor consists of a toothed soft iron core. With this material, the magnetic field disappears when the stator current is switched off. When the current is switched on, the magnetic flux flows through the soft iron core of the rotor. The rotation of the rotor occurs because the nearest tooth of the rotor is attracted by the toothed stator (fixed, immovable part of the motor), as this reduces the magnetic resistance. As the reluctance stepper motor does not contain any permanent magnets, it also has no cogging torque when the current is switched off, unlike the permanent magnet stepper motor.
2. Permanent magnet stepper motor:
   In permanent magnet stepper motors, the stator consists of soft iron and the rotor of permanent magnets with alternating north and south poles. The stator magnetic field is used to align the permanent magnet rotor in such a way that a rotary movement is created. With permanent magnet stepper motors, the number of poles (and therefore the resolution) is limited. One advantage over the reluctance stepper motor is its greater torque. The larger induction stroke (inner magnetic field from -Bmax to +Bmax) results in higher magnetic forces, which leads to a higher torque. In principle, the PM stepper motor is a synchronous motor in which the resolution has been increased by increasing the number of pole pairs.
3. Hybrid stepper motor:
   Hybrid stepper motors combine the properties of reluctance and permanent magnet stepper motors. Hybrid stepper motors have a stator with multiple toothed stator poles and a permanent magnet rotor. Standard hybrid stepper motors have 200 rotor teeth and move at step angles of 1.8° each. Hybrid stepper motors are used in numerous applications due to their high static and dynamic torque and their very high stepping speed.
4. Disk magnet stepper motors:
   Disc magnet stepper motors are advanced microstepping motors that offer more dynamic motor performance, finer step resolution and higher acceleration than other stepper motor types. The thin disk magnet enables finer step resolutions per given size, higher acceleration and a higher peak speed than conventional stepper motors. Disc magnet motors are particularly suitable for applications that require the precision of a stepper motor and the speed and acceleration of a brushless DC motor. A closed control loop provides a cost-effective advantage over a servo solution.

Areas of application for stepper motors:

Stepper motors are suitable for many different motion control applications. They are often used in areas where precise positioning is required:

1. Industrial manufacturing technology:
E.g. in CNC milling machines to control the movements of the milling cutter along the X, Y and Z axes,

2. 3D printers:
In 3D printers, to precisely move the extruder and printing platform.

3. Robotics:
The joints of a robotic arm are often driven by stepper motors to ensure accurate movements.

4. Control and automation:
They are widely used in industrial control systems, e.g. for controlling valves and conveyor belts.

5. Optical systems:
Stepper motors are used in telescopes and microscopes to finely adjust the position of lenses and mirrors.

6. Medical technology:
Stepper motors can be found in medical devices that require precise movements, such as syringe pumps or dosing devices.

Advantages of stepper motors:

• Due to the fixed stepping motion, stepper motors can approach positions very precisely without the need for a feedback system such as an encoder.
• They are controlled by simple pulse sequences, which facilitates integration into electronic systems.
• Very high torque even at low speeds.
• Fast start thanks to high torque, easy stop thanks to high holding torque. This makes it possible to change the direction of rotation quickly. The simple design of the start-stop characteristic is also very important for many applications.
• Another important positive feature is the simple motor control.

Disadvantages of stepper motors:

• Stepper motors can lose steps in case of overload or insufficient power supply, which leads to inaccuracies.
• At certain speeds, stepper motors can develop resonances that lead to vibrations and noise.
• Stepper motors can also consume power at standstill, which increases energy consumption.

Stepper motors are versatile and reliable drives that are indispensable in many precise and demanding applications. The choice of the right motor and careful selection of the controller are crucial in order to take full advantage of this technology.

Below you will find an overview of the most important criteria to look out for when purchasing stepper motors:

When buying stepper motors, there are several important factors to consider to ensure that the motor is suitable for the application in question.

• The step angle indicates how many degrees the motor shaft moves with each step. A smaller step angle allows for higher resolution and therefore more precise movements. For applications that require high precision, a small step angle is preferable.
• The holding torque is the maximum torque that the motor can hold in a static position. A higher holding torque is important if the motor has to hold heavy loads, especially at standstill.
• The rated current indicates how much current the motor requires under full load and the rated voltage indicates the operating voltage of the motor. The motor controller (driver) must support these parameters. A higher rated current can deliver more power, but also requires appropriate cooling.
• The step frequency indicates how many steps the motor can perform per second. A higher step frequency enables faster movements, but also requires correspondingly designed control electronics.
• Encoders monitor the position of the motor shaft and can be used for precise control. Encoders are essential in applications that require feedback of the actual position.
• The size of the motor, often specified in NEMA formats (e.g. NEMA 17, NEMA 23), describes the physical dimensions of the motor. The size should match the mechanical design of the application
• The shaft type (smooth, flat, or threaded) and diameter determine how the motor is mechanically connected. The shaft must be compatible with the gearbox or coupling used.
• Unipolar and bipolar motors differ in the type of windings and circuits. Bipolar motors often offer more torque, while unipolar motors are easier to control.
• Environmental conditions such as temperature, humidity and dust can affect the performance and service life of the motor. The motor should be suitable for the specific environmental conditions in which it will be operated.
• It is advisable to select the motor not only on price, but also on quality and reliability.

Choosing the right stepper motor depends heavily on the specific requirements of the application. It is worth checking the technical data carefully and possibly consulting experts to make the best choice.

Stepper motors can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Stepper motors from all over the world can be found on Exportpages.