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A 100 k VA, 2400 / 240V, 50 Hz single phase transformer has an exciting current of 0.64 A and a core loss of 700 watts, when its high-voltage side is energised at rated voltage and frequency. If load current is 40 A at 0.8 power factor of on the LV side then the primary current will be _______ A .
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- 4.58 A
- 45 A
- 45.8 A
- None of these
Correct Option: A
Load current, IL (to h.v. side) = 4 ∠ – 37° amp.
| IC = | = | = 0.292 A | ||
| V | 2400 |
Iφ = √Ie² - IC²
= √0.64² - 0.292² = 0.569
Primary current, I1 = IC - j Iφ + IL
= 0.292 – j0.569 + 3.19 – 2.40j
= 3.48 – 2.96 j = 4.58 ∠ – 40.3°
