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For power measurement of three phase circuit by two wattmeter method, when the value of power factor is less than 0.5 lagging:

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For power measurement of three phase circuit by two wattmeter method, when the value of power factor is less than 0.5 lagging: One of the wattmeter connections will have to be reversed

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Measurement of power and power factor of a 3-phase system by two wattmeter method can be obtained in case of  1. Balanced load and balanced source  2. Balanced source with 3-phase 3-wire unbalanced load  3. Unbalanced source with 3-phase 3-wire balanced load  4. Balanced source with 3-phase 4-wire unbalanced load  5. unbalanced and unbalanced source    (a) 1 only (b) 2, 3 and 5 (c) 1, 2, 3, 4 and 5 (d) 1, 2, 3 and 5 

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