Question

reading in two wattmeter method when phase sequence is reverse

Answer 1

A two-watt-meter system is one in which 2 watt-meters are inserted in any of the two lines and the potential coil of each is joined to the third line. Any reading taken after reversing the pressure coil is taken as a negative value.

Also, the two watt-meters used for measuring the three-phase power will interchange their readings after they have been subjected to a phase sequence reversal. However, the magnitudes of the currents and the component voltages in these balanced systems will not be affected by the phase sequence reversal.