Which of the following devices are required to measure three phase balanced power?
- A. One watt meter
- B. One watt meter and one voltage transformer of 1 : 1 ratio
- C. One watt meter and two voltmeters
- D. None of the above
Answer: A. One watt meter
Explanation: For a balanced 3-phase load, total power can be measured using a single wattmeter by connecting its current coil in one line and creating a star/artificial neutral connection (Ptotal = 3·W).