MGVCL Exam Paper (30-07-2021 Shift 2) A single phase motor connected to 415 V, 50 Hz supply takes 30 A at a power factor of 0.7 lagging. Calculate the capacitance required in parallel with the motor to raise the power factor to 0.9 lagging. 66.32 µF 96.32 µF 86.32 µF 76.32 µF 66.32 µF 96.32 µF 86.32 µF 76.32 µF ANSWER EXPLANATION DOWNLOAD EXAMIANS APP P = VIcosφ = 8715 wattQ = VAR required to improve PF = P(tanφ₁ - tanφ₂) = 4670 VARCapacitive Reactance, Xc = V²/Q = 36.8790 ohm.C = (2πfXc)⁻¹ = 86.314 μF
MGVCL Exam Paper (30-07-2021 Shift 2) If all the devices are connected to a central hub, then the topology is called Tree Topology Star Topology Bus Topology Tree Topology Tree Topology Star Topology Bus Topology Tree Topology ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) In transformer, bushing failure occurs due to(i) transformer vibrations(ii) dielectric losses(ii) partial discharge (i) and (iii) only (ii) and (iii) only (i) and (ii) only (i), (ii) and (iii) (i) and (iii) only (ii) and (iii) only (i) and (ii) only (i), (ii) and (iii) ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) Which one of the following is the committee on poverty estimation? S.S.Tarapore committee Ad hoc committe Karve committee Tendulkar committee S.S.Tarapore committee Ad hoc committe Karve committee Tendulkar committee ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) The necessary equation to be solved during the load flow analysis using Fast-Decoupled method is given below:where B' and B'' are formed using the imaginary part of the bus admittance matrix, Ybus. If the system consists of 6 buses of which one of the bus is slack bus and 2 bues are voltage regulated buses, then then the matrix B' is of order ____and the matrix B'' is of order____, respectivity.∆P/|Vi| = - B'∆δ∆Q/|Vi| = - B''∆|V| 5 and 3 3 and 5 6 and 3 3 and 6 5 and 3 3 and 5 6 and 3 3 and 6 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In Fast-decoupled method,Order of B' = No. of PV buses = 5Order of B'' = No. of PQ buses = 3
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 50 kVAR 25 kVAR 75 kVAR 100 kVAR 50 kVAR 25 kVAR 75 kVAR ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The reactive VAR required = kW*(tanφ1 -tanφ2)Cosφ1 = 0.8φ1 = 36.87 deg.Cosφ2 = 0φ2 = 0 deg.kVAR required = kW*(tan(36.87) - tan(0))= 300*1000(0.75)= 225.00 kVARPer phase value = 225.00/3= 75 kVAR
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