In case of power measurements by two wattmeter method in a balanced 3-phase system with pure inductive load
- A. both wattmeters will indicates the same value but with opposite signs
- B. both wattmeters will indicate zero
- C. both the wattmeters will indicate the same value same sign
- D. one wattmeter will indicate zero and the other will indicate some non-zero value
Answer: A. both wattmeters will indicates the same value but with opposite signs
Explanation: For a purely inductive load (φ = 90°) W1 = VI cos(30°−90°) = +0.5VI and W2 = VI cos(30°+90°) = −0.5VI: equal magnitudes, opposite signs.