MGVCL Exam Paper (30-07-2021 Shift 2)
A coil having an inductance of 100 mH is magnetically coupled to another coil having an inductance of 900 mH. The coefficient of coupling between the coils is 0.45. Calculate the equivalent inductance if the two coils are connected in series opposing.

1135 mH
932 mH
1270 mH
730 mH

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MGVCL Exam Paper (30-07-2021 Shift 2)
A 50 Hz synchronous generator is connected to an infinite bus through a line. The p.u. reactances of generator and the line are j0.3 p.u. and j0.2 p.u. respectively. The generator no load voltage is 1.1 p.u. and that of infinite bus is 1.0 p.u. The inertia constant of the generator is 4 MW-sec/MVA. Determine the frequency of natural oscillations if the generator is loaded to 60% of its maximum power transfer capacity and small perturbation in power is given.

1.42 Hz
1.62 Hz
1.52 Hz
1.32 Hz

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MGVCL Exam Paper (30-07-2021 Shift 2)
Consider a solar PV plant with the following specific conditions: Analysis period: 1 year
Measured average solar irradiation intensity in 1 year: 120 kWh/m²
Generator area of the PV plant: 10 m²
Efficiency factor of the PV modules: 15%
Electrical energy actually exported by plant to grid: 110 kWh
Calculate the performance ratio.

0.7111
0.8111
0.5111
0.6111

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MGVCL Exam Paper (30-07-2021 Shift 2)
The voltage applied to a transformer primary is increased keeping V/f constant. With this, the core loss ____ and the magnetizing current (Im) ____

remains constant, decreases
increases, remains constant
increases, increases
decreases, increases

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MGVCL Exam Paper (30-07-2021 Shift 2)
A 3-phase motor load has a p.f. of 0.397 lagging. The two wattmeter method used to measure power show the input as 30 kW. Find the reading on each wattmeter.

W1 = -5 kW and W2 = 35 kW
W1 = -10 kW and W2 = 40 kW
W1 = 10 kW and W2 = 20 kW
W1 = 5 kW and W2 = 25 kW

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