Three-Phase Wattmeter:

Overall power in a 3ø circuit is the sum of the powers of the separate phases. The total power could be measured through placing a wattmeter in every phase above figure display that; thus, this method is not feasible because it is frequently impossible to break into the phases of a delta load. That also might not be feasible for the Y load, because the neutral point to that the wattmeters must be linked is not always accessible.

Figure: Wattmeters in Each Phase

Generally, only two wattmeters are used in making 3  power measurements in the figure.

Within balanced 3ø  systems, along with any power factor, whole power is calculated through adding the A and B phase powers. Given Equation (14-17) is the mathematical representation for calculating total power (P_T).

P_T = W_A + W_B                                                                                                   (14-17)

where

W_A  and W_B  are the power readings in Phase A and Phase B

Figure: Two Wattmeters to Measure 3   Power