A stepper motor is a type of brushless DC motor. It is designed to provide a certain number of defined steps per revolution. For example, a motor with 200 steps/revolution will offer a position resolution of 1.8°/pulse (360°/200 pulses). Each time the motor is pulsed by the stepper controller, it will move in the forward or reverse direction, according to the number of pulses received. In the aforementioned example, 100 pulses would cause the motor to rotate 180°.
Advantages of stepper motors
A stepper motor is able to offer open-loop positioning, which is a big advantage over open-loop induction motors, which are not able to provide positioning. Most stepper motors do not include any feedback, which lowers the overall cost of a stepper and control solution. Their low cost is a primary reason for their widespread use. One advantage in industrial applications is that stepper motors can be run with a DC-powered stepper drive. They do not require larger inverters that input 230/460VAC, or bulky fusing and cabling, which can be quite significant with multi-axis applications.
Limitations of stepper motors
It is possible for a stepper to ‘lose’ position. This can happen if it does not provide sufficient torque to move the shaft and load...
Read the full article in DPA's January issue