It is an electrodynamics and electromagnetic equipment.
These motors are also referred to as step motors or stepping motors.
On account of its unusual construction, operation and characteristics it is difficult to define a stepper motor. Definition given in British Standard specification (BSS) is
A stepper motor is brushless dc motor whose rotor rotates in discrete angular displacements when its stator windings are energized in a programmed manner. Rotation occurs because of magnetic interaction between rotor poles and poles of the sequentially energized winding. The rotor has no electrical windings, but has salient and magnetic/or magnetized poles.
The stepper motor is a digital actuator whose input is in the form of digital signals and whose output is in the form of discrete angular rotation. The angular rotation is dependent on the number of input pulses the motor is suitable for controlling the position by controlling the number of input pulses. Thus they are identically suited for open position and speed control.
v Graph plotters
v Tape driver
v Disk Drives
v Machine Tools
v X-Y Recorders
v Robotics space Vehicle
v IC Fabrication and Electric Watches