Which one of the following devices produces incremental motion through equal pulses?

Explanation:

Stepper Motor:

• Stepper motors operate on the control pulses received and rotate in discrete steps. 
• Each pulse moves the shaft through a fixed angle. 
• On the other hand, ordinary electrical a.c and d.c drives are analog in nature and rotate continuously depending on the magnitude and polarity of the control signal received.
• The discrete nature of the operation of a stepper motor makes it suitable for directly interfacing with a computer and direct computer control.
• A servo motor is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration

AC servomotors: 

• AC motors convert AC current into mechanical energy.

DC servomotors:

• DC motors convert DC current into mechanical energy.

Series motor: 

• In series motors, a linear relationship exists between the current flowing through the field windings and the amount of torque produced.
• Heavy currents flow through the very thick series field windings, large torques are produced in series motors.
• Series motor is used where high power is needed for example elevator and hoist installations.