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Two watt-meters connected to measure the total power on a three-phase system supplying a balanced load reads 10.5 kW and -2.5 kW respectively. Then the total power factor is?(a) 0.334(b) 0.684(c) 0.52(d) 0.334I got this question in an online interview.My enquiry is from Advanced Miscellaneous Problems on Measurement of Power in chapter Measurement of Power and Related Parameters of Electrical Measurements |
Answer» CORRECT choice is (d) 0.334 The EXPLANATION: w1 = 10.5 kW, W2 = -2.5 kW ∴ W = w1 + w2 = 8 kW Also, tan ∅ = 2.81 ∴ ∅ = 70.43° or, cos ∅ = 0.3347. |
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