To measure the electrical power in a balanced three-phase circuit, which instrument should be used?

To measure the electrical power in a balanced three-phase circuit, which instrument should be used?

• A. Voltmeter
• B. Ammeter
• C. Wattmeter
• D. Ohmmeter

Answer: (C)

In a balanced three-phase circuit, the measurement of electrical power is most accurately accomplished using a wattmeter. This instrument is specifically designed to measure the real power consumed by the electrical load, which is expressed in watts. The wattmeter can account for both the voltage and current in the circuit, as well as the phase difference between them, which is essential for calculating power in AC circuits. While a voltmeter measures voltage and an ammeter measures current, they do not directly provide a power measurement without additional calculations. The power in a three-phase system can also depend on the configuration (wye or delta) and requires taking into account the phase angles, which the wattmeter does automatically. An ohmmeter, on the other hand, measures resistance and has no relevance in power measurement. Therefore, the wattmeter is the appropriate instrument to use in this scenario for measuring electrical power in a balanced three-phase circuit.

In a balanced three-phase circuit, the measurement of electrical power is most accurately accomplished using a wattmeter. This instrument is specifically designed to measure the real power consumed by the electrical load, which is expressed in watts. The wattmeter can account for both the voltage and current in the circuit, as well as the phase difference between them, which is essential for calculating power in AC circuits.

While a voltmeter measures voltage and an ammeter measures current, they do not directly provide a power measurement without additional calculations. The power in a three-phase system can also depend on the configuration (wye or delta) and requires taking into account the phase angles, which the wattmeter does automatically.

An ohmmeter, on the other hand, measures resistance and has no relevance in power measurement. Therefore, the wattmeter is the appropriate instrument to use in this scenario for measuring electrical power in a balanced three-phase circuit.