DC motors that move in discrete steps are called stepper motors. They have multiple coils organized into “phases,” groups. The motor will rotate one step at a time by sequentially activating each phase.
Positioning and/or speed control can be extremely precise with computer-controlled stepping. In many precision motion control applications, stepper motors are therefore the motor of choice.
There are many different sizes, designs, and electrical properties for stepper motors. What you need to know to choose the right motor for the job is covered in detail in this guide.
What are stepper motors good for?
Positioning: Because steppers move in precise, repeatable steps, they excel in applications like 3D printers, CNC, camera platforms, and X-Y plotters that require precise positioning. The read/write head is also moved by stepper motors in some disk drives.
Speed Control: For robotics and process automation, precise movement increments also make it possible to precisely control rotational speed.
Torque at Low Speeds: At low speeds, normal DC motors have little torque. For applications requiring high precision at a low speed, stepper motors are a good choice because they have maximum torque at low speeds.
What are their limitations?
Low Efficiency: Stepper motors consume current independently of load, in contrast to DC motors. When they are not working, they draw the most recent. As a result, they frequently become hot.
Low Low Speed Torque: Stepper motors typically have lower low speed torque than high speed torque. Some steppers are made to perform better at high speeds, but in order to do so, they need to be paired with the right driver.
Lack of Feedback: Most steppers lack position feedback, in contrast to servo motors. Despite the fact that running “open loop” allows for extremely precise operation. Most of the time, limit switches or “home” detectors are needed for safety or to set a reference position.