Stepping Servo Motors
A stepping motor is defined as a rotary device whose output shaft moves in discrete steps when excited from a switched DC supply. Stepping motors are very practical devices for converting digital pulse inputs into analogue shaft-output (or rotary) motion as required in modern electric or electronic equipment. Each shaft revolution can be expressed in terms of a number of discrete identical steps or increments. Each step can be triggered by a single pulse. Stepping motors can be made with a rotor made of permanent magnets or DC energized. In the latter case, brushes must be used to energize the rotor. The principal operation of both types are shown in Fig. 5.1.