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A 3 phase, 10 kW, 400 V, 4 pole, 50 Hz, star connected induction motor draws 20 A on full load. Its no load and blocked rotor test data are given below :
No Load test : 400V 6 A 1002 W Blocked Rotor test : 90 V 15 A 762 W
Neglecting copper loss in no Load test and core loss in Blocked Rotor test, estimate motor 's full load efficiency.
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- 76%
- 81%
- 82.4%
- 85%
Correct Option: B
| Value of power loss in case of blocked rotor at full load = |  |  | 2 | × 762 = 1354.6 watts | |
| 15 |
∴ Total losses= 1354.6 + 1002 = 2356.6 watts.
Total input = 10000 + 2386.6 = 12356.6
| ∴ % Efficiency = | × 100 = 81% | |
| 12356.6 |
