Measurement of 3-Phase Active Power by 1 Wattmeter Method

APPARATUS

Measurement of 3-phase Active Power by one wattmeter is used for 3 phase balanced load only. The current coil of the wattmeter is connected in one of the lines in series. One end of the pressure coil is connected to the same line and the readings are taken by connecting the other terminal of the pressure coil alternatively to other 2 lines. The sum of the two readings gives the total active power.