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Power in Three-Phase Circuit by Three-Wattmeter Method

Author: E.E. Kimberly

The power in a three-phase system may be measured by placing a single-phase wattmeter in each phase and adding the three readings. This method is possible in a A system only if the phase units can be separated and in a Y-system only if the neutral or wye point can be reached. Fig. 9-5 shows the proper arrangement of wattmeters. In either (a) or (b),


Fig. 9-5. Measurement of 3-Phase Power by Three-Wattmeter Method

By equation (9-1), in which V01 is used instead of V02, Therefore,


ee_101-44.png (9-4)

This value is the power factor of the balanced system whether Δ-connected or Y-connected.

Last Update: 2010-10-06