Three Phase Watt Meter Review

Electronic Electrical Devices

Total power in a 3-Theta circuit is the sum of the powers of the separate phases. The total power could be measured by placing a wattmeter in each phase See below; however, this method is not feasible since it is often impossible to break into the phases of a delta load. It also may not be feasible for the Y load, since the neutral point to which the wattmeters must be connected is not always accessible.

Normally, only two wattmeters are used in making 3-Theta power measurements .

In balanced 3-Theta systems, with any power factor, total power is calculated by adding the A and B phase powers. The equation below is the mathematical representation for calculating total power (PT).

P_T = W_A + W_B

Where:

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