Question

Assertion (A): Servomotors have heavier rotors and lower R/X ratio as compared to ordinary motors of similar ratings.

Reason (R): Servomotor should have smaller electrical and mechanical time constants for faster response.

Reason (R): Servomotor should have smaller electrical and mechanical time constants for faster response.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A is false but R is true

The question was asked in examination.

My question is from Differential Equations of Physical Systems and Dynamics of Robotic Mechanisms topic in portion Mathematical Models of Physical Systems of Control Systems

Answer 1

Right option is (d) A is false but R is true

To explain: Ac servomotors are essentially induction motor with low X/R ratio for the rotor which has very low inertia.