SERVO motor is a rotary ACTUATOR or a motor that allows for precise control in terms of angular position, acceleration, and VELOCITY.Basically, it has certain capabilities that a REGULAR motor does not have. Consequently, it makes USE of a regular motor and pairs it with a sensor for position feedback.The mechanical time constant represents the amount of time for an unloaded motor to rise to 63.2% of its final velocity after the application of a command voltage.The time constant of a servo control system can be decreased by decreasing the viscous damping of the system.The time constant of a servo control system can be decreased by decreasing the inertial of the system.