MGVCL Exam Paper (30-07-2021 Shift 3) A three phase four pole 50 Hz induction motor has a rotor resistance of 0.02 Ω/phase and stand-still reactance of 0.5 Ω/phase. Calculate the speed at which the maximum torque is developed. 1440 rpm 1475 rpm 1525 rpm 1500 rpm 1440 rpm 1475 rpm 1525 rpm 1500 rpm ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Condition for maximum torque,Sm = R2/X2= 0.04Ns = (120*f)/P= (120*50)/4= 1500 rpmS = (Ns - Nr)/NsNr = Ns(1 - Sm)= 1500*(1 - 0.04)= 1440 rpm
MGVCL Exam Paper (30-07-2021 Shift 3) The threshold voltage of an N-channel enhancement mode MOSFET is 0.5 V. When the device is biased at a gate voltage of 3 V, pinch-off would occur at a drain voltage of 4.5 V 1.5 V 3.5 V 2.5 V 4.5 V 1.5 V 3.5 V 2.5 V ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Equation is given by:Vds = Vgs - VtVds = 3 - 0.5Vds = 2.5 V
MGVCL Exam Paper (30-07-2021 Shift 3) Find the word which is correctly spelt from the given options. Obecity Syndrome Seriuous Abolishid Obecity Syndrome Seriuous Abolishid ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 3) In a series RLC circuit, the supply voltage is 230 V at 50 Hz. The resonant current is 2 A at the resonant frequency of 50 Hz. Under the resonant condition, the voltage across the capacitor is measured to be equal to 460 V. What are the values of L and C? 0.53 mH and 15.83 pF 0.73 mH and 13.85 pF 0.73 H and 13.85 pF 0.53 H and 15.83 pF 0.53 mH and 15.83 pF 0.73 mH and 13.85 pF 0.73 H and 13.85 pF 0.53 H and 15.83 pF ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Vc = I*Xc460 = 2*(1/(2*ᴨ*50*C))C = 2/(460*2*50*ᴨ)= 1.385*10⁻⁵ F= 13.85 FV_L = I*X_LL = V/(I*2*ᴨ*f)= 460/(2*ᴨ*50*2)= 0.7345 H
MGVCL Exam Paper (30-07-2021 Shift 3) Two-wattmeter method is used to measure the power taken by a 3-phase induction motor on no load. The wattmeter readings are 400 W and -50 W. Calculate the reactive power taken by the load 350/√3 VAR 350√3 VAR 450√3 VAR 450/√3 VAR 350/√3 VAR 350√3 VAR 450√3 VAR 450/√3 VAR ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Reactive power taken (Q) = √3*(W1 - W2)= √3*(450 + 50)= √3*450 kVAR
MGVCL Exam Paper (30-07-2021 Shift 3) In a power network, 375 kV is recorded at a 400 kV bus. A 45 MVAR, 400 kV shunt reactor is connected to the bus. What is the reactive power absorbed by the shunt reactor? 59.55 MVAR 49.55 MVAR 39.55 MVAR 69.55 MVAR 59.55 MVAR 49.55 MVAR 39.55 MVAR 69.55 MVAR ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Q = V²/XX = 400²/45= 3555.55 ohmFor 375 kV,Q = 375²/3555.55= 39.55 kVAR
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