A shunt generator has a critical field resistance of 200 ohm at a speed of 800r.p.m. If the speed of the generator is increased to 1000r.p.m., what is the change in critical field resistance of the generator?
- A. Decrease to 160 ohm
- B. Remains the same at 200 ohm
- C. Increases to 250 ohm
- D. Increases to 312.5 ohm
Answer: C. Increases to 250 ohm
Explanation: Critical field resistance is proportional to speed: 200×1000/800 = 250 Ω.