MGVCL Exam Paper (30-07-2021 Shift 2)
The wind speed increases with height because of

reduction of drag effect of the earth surface
reduction in the gravitational force
reduction in lift effect of the air
enhancement of drag effect on the earth surface

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MGVCL Exam Paper (30-07-2021 Shift 2)
A three-phase, 12 kV, 50 Hz and 300 kW load is operating at 0.8 pf lag. If the pf is to be improved to unity, using star connected capacitor, the per phase value of the reactive VAR required is:

100 kVAR
25 kVAR
50 kVAR
75 kVAR

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

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MGVCL Exam Paper (30-07-2021 Shift 2)
In the circuit of figure, the switch is closed to position-1 for a long time. At t = 0 the switch position is changed from postion-1 to postion-2. Find an expression for the current i(t).

i(t) = (E/R) cos√(LC) t A
i(t) = (E/R) cos[1/√(LC)]t A
i(t) = (E/R) sin√(LC) t A
i(t) = (E/R) sin[1/√(LC)]t A

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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.

1.32 Hz
1.42 Hz
1.62 Hz
1.52 Hz

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