Which of the following statement is correct for two wattmeters method of power measurement in 3 phase circuit?

Electronics and Communication Engineering (ECE) : Measurements and Instrumentation - Quiz(MCQ)

When two wattmeters have equal readings power factor is 0.5.

When power factor is 1, one of the wattmeters readings is zero

When the two wattmeter read equal and opposite, p.f. is zero.

Power can be measured by this method only for star connected loads

Correct Answer : Option (C) : When the two wattmeter read equal and opposite, p.f. is zero.

Explanation : When p.f. is zero, active power is zero and the two redaings are equal and opposite.

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