Stepper motors are high pole count DC motors driven by a DC pulse train. Machine designers often create systems designed to use stepper motors at relatively high rpm based on the maximum motor speed rating (typically 3000 rpm) and the motor torque versus speed curve.
Difference between a stepper motor and a hybrid stepper motor
There are two types of stepper motors: hybrid stepper motor, which features a series of coils and magnets wrapped in copper wire, and high torque stepper motor, which consists of rugged steel coils and magnets. In general, hybrid motors offer better airflow and longevity, while high-torque motors offer more horsepower and are better suited for high-performance applications, with some stepper motors also featuring hybrid designs.
Do stepper motors have high torque?
Stepper motors are often used in devices that require high torque, for example, stepper motors are often used to open and close the tailgate of a car, where high torque is necessary to provide sufficient strength to open and close the rear flap despite the force of the spring mechanism used to hold it closed. In other applications, such as older cameras, stepper motors are used to move film through the camera body.
When it comes to motors, you may think of devices that move in a linear direction. But motors can also turn or rotate in a circular motion. Stepper motors are rotary motors that are commonly used in devices such as 3D printers, CNC machines and other automated machines, and they are often used with a set of gears, which allows them to achieve very high torque levels.
What is a hybrid stepper motor?
Hybrid stepper motors use a hybrid transmission or hybrid stepper system to increase the power and torque of the motor. This hybrid transmission system allows the motor to work like a conventional or linear stepper motor, moving in only one direction, but also allows it to work like a DC motor, moving in both directions.
This hybrid system allows the hybrid stepper motor to have finer resolution or step lengths, thereby increasing the performance and efficiency of the motor, so the stepper motor is more powerful than a conventional or linear stepper motor, but uses less energy.
Advantages of a hybrid stepper motor
Combining the best features of traditional stepper motors and servo motors, the hybrid stepper motor provides higher torque, higher speed and longer life. Hybrid stepper motors have wire windings wrapped around a magnetic core, and when current is applied to the windings, the magnetic field causes the core to rotate, which in turn causes the coil to rotate and the shaft to move.
Why can’t a stepper motor produce high torque at high speed?
Another factor that limits the torque generated by a stepper motor at high speed is the rate of current rise in the windings (dI/dt), which is proportional to the applied voltage (V) and inversely proportional to the inductance of the motor (L). When the speed of the stepper motor is increased, the torque decreases.
Conclusion
The most notable stepper motor performance characteristics are precise positioning, good holding torque, and good low-speed torque characteristics. But there are some applications that require high torque at high speeds and the design/control specifications require the use of stepper motors. Although stepper motors aren’t notable for their ability to produce high torque at high speed, it is possible, in some applications, to achieve both.