MGVCL Exam Paper (30-07-2021 Shift 2) In a synchronous motor with field under excited, the power factor will be zero leading unity lagging zero leading unity lagging ANSWER EXPLANATION DOWNLOAD EXAMIANS APP For synchronous motor,Under excitation - Lagging power factorOver excitation - Leading power factorFor synchronous generatorUnder excitation - Leading power factorOver excitation - lagging power factor
MGVCL Exam Paper (30-07-2021 Shift 2) If the velocity of electromagnetic wave in free space is 3 × 10⁸ m/s, then the velocity in a medium with εr of 4.5 and μr of 2 would be 1 × 10⁸ m/s 27 × 10⁸ m/s 9 × 10⁸ m/s 3 × 10⁸ m/s 1 × 10⁸ m/s 27 × 10⁸ m/s 9 × 10⁸ m/s 3 × 10⁸ m/s ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Speed of EM wave in medium = C/√(εr*μr)= (300000000)/√9= 300000000/3= 100000000= 1*10⁸ m/s
MGVCL Exam Paper (30-07-2021 Shift 2) Which of the following is an application layer service? Network virtual terminal Mail service Mail service File transfer, access and management Network virtual terminal Mail service Mail service File transfer, access and management ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) The expression for voltage regulation of a short transmission line for leading power factor is given by: ____, where, 'I' is the line current, 'V_r' is the receiving end voltage, 'R' is the line resitance and 'X' is the line reactance. (IRcosφ_r + IXsinφ_r)/V_r (IXcosφ_r - IRsinφ_r)/V_r (IXcosφ_r + IRsinφ_r)/V_r (IRcosφ_r - IXsinφ_r)/V_r (IRcosφ_r + IXsinφ_r)/V_r (IXcosφ_r - IRsinφ_r)/V_r (IXcosφ_r + IRsinφ_r)/V_r (IRcosφ_r - IXsinφ_r)/V_r ANSWER EXPLANATION DOWNLOAD EXAMIANS APP For lagging power factor = (IR*cosφ + IXsinφ)/V_rFor leading power factor = (IR*cosφ - IXsinφ)/V_rZero voltage regulation occurs on leading power factor only.
MGVCL Exam Paper (30-07-2021 Shift 2) Vikram Seth is associated with which of the following fields? Politician Sports Literature Music Politician Sports Literature Music ANSWER DOWNLOAD EXAMIANS APP
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: 50 kVAR 75 kVAR 25 kVAR 100 kVAR 50 kVAR 75 kVAR 25 kVAR 100 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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