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A single phase induction motor draws 12 MW power at 0.6 lagging power. A capacitor is connected in parallel to the motor to improve the power factor of the combination of motor and capacitor to 0.8 lagging. Assuming that the real and reactive power drawn by the motor remains same as before, the reactive power delivered by the capacitor in MAR is __________.
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- 6.97
- 6.97 to 7.03
- 7.03
- 6
Correct Option: B
P1 = 12 MW
cos φ1 = 0.6
Q1 = P1 tan φ1
| = P1 |  |  | = 16 MVAR | ||
| 6 |
When p.f. becomes 0.8
⇒ cos θ2 = 0.8
Then, Q2 = P1 tan φ2 [real power remain same]
| = 12 | | | = 9 MVAR | ||
| 8 |
Since, reactive power drawn by motor remain the same, reactive power supplied by capacitor
QC = Q1 – Q2 = 16 – 9 = 7 MVAR
