ABSTRACT
A stepper motor is an electric machine that rotates in discrete angular increments or steps. Stepper motors are operated by applying current pulses of a specific frequency to the inputs of the motor. Each pulse applied to the motor causes its shaft to move a certain angle of rotation, called a stepping angle. Since the input signal is converted directly into a requested shaft position without any rotor position sensors or feedback, the stepper motor has the following advantages:
x Rotational speed proportional to the frequency of input pulses x Digital control of speed and position x No need of feedback sensor for open loop control x Excellent acceleration and deceleration responses to step commands
The stepper motor also possesses drawbacks such as the possibility of losing synchronism, harmonic resonance, and small oscillations at the end of each step. With the above parameters in mind, the stepper motor is used in applications such as printers, plotters, X-Y tables, facsimile machines, barcode scanners, image scanners, copiers, medical apparatus, and other devices.
