A DC shunt motor is running at 1200 rpm, when excited with 220V DC. Neglecting the losses and saturation, the speed of the motor when connected to a 175 V DC supply is
- A. 750 rpm
- B. 900 rpm
- C. 1050 rpm
- D. 1200 rpm
Answer: D. 1200 rpm
Explanation: Neglecting armature resistance drop, back EMF Eb ≈ V. Since flux Φ ∝ V, speed N ∝ Eb/Φ remains essentially unchanged at 1200 rpm.