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A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coil is 10 A, then the input voltage and current in the primary coil are:
- 440 V and 20 A
- 440 V and 5 A
- 220 V and 20 A
- 220 V and 10 A
Correct answer: 440 V and 5 A
Solution
Vs = P/Is = 2200/10 = 220 V. With Np/Ns = 300/150 = 2, Vp = 2*220 = 440 V. Ip = P/Vp = 2200/440 = 5 A. So input is 440 V and 5 A.
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