A wattmeter is marked 15 A/30 A, 300 V/600 V and its scale is marked up to 4500 watts. When the meter is connected to 30 A, 600 V, the point indicated 2000 watts

A wattmeter is marked 15 A/30 A, 300 V/600 V and its scale is marked up to 4500 watts. When the meter is connected to 30 A, 600 V, the point indicated 2000 watts. The actual power of the circuit is

Right Answer is:

8000 watts

SOLUTION

Power consumed by wattmeter = CT ratio × PT ratio × VIcosΦ……..1

In the above question

Power consumed by wattmeter = 2000 watts

CT ratio = 15 / 30

PT ratio = 300 / 600

VI = 600 × 30

Putting all the value in equation number 1 we get

2000=(15/30) × (300/600) × 600 × 30 × cosΦ

CosΦ = 0.4444

Power = VI cosΦ = 600 x 30 x 0.4444

Power = 7999.2 ≅ 8000 watts

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