ABSTRACT
Stepper motors convert electrical pulses into discrete units of rotational movement, which can be controlled independently and without a feedback mechanism. Rotation of a stepper motor requires that the electrical pulses applied to the stator windings follow a definite sequence. The speed of rotation of a stepper motors is determined by the frequency of the pulses and the amount of rotation by the number of pulses. Stepper motors are a good choice in applications that require control over motor speed, angle of rotation, direction of rotation, position, or synchronization. They find frequent use in robotics, office equipment such as printers and fax machines, in floppy and hard disk drives, in medical equipment, in computer control of machine tools, and in automobiles. The sequence in which the windings or winding sections are activated in a unipolar or bipolar stepper motor is called the stepping mode. Three stepping modes are most common, although a fourth mode, called microstepping, is occasionally used.
