If the terminal voltage of a DC shunt motor is halved, keeping load torque varying as square of speed. Then, which of the following statements are correct? i. Speed is halved ii. Speed remains unaltered iii. Armature current is doubled iv. Armature current is unaltered
- A. i and iii
- B. i and iv
- C. ii and iii
- D. ii and iv
Answer: C. ii and iii
Explanation: For a DC shunt motor, flux Φ ∝ V. If V is halved, Φ is halved. Speed N ∝ V/Φ remains unaltered (ii). Since load torque T ∝ N² is unchanged, armature current Ia ∝ T/Φ doubles (iii).