MGVCL Exam Paper (30-07-2021 Shift 2) The wind speed increases with height because of reduction in lift effect of the air reduction of drag effect of the earth surface reduction in the gravitational force enhancement of drag effect on the earth surface reduction in lift effect of the air reduction of drag effect of the earth surface reduction in the gravitational force enhancement of drag effect on the earth surface ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Wind speed increases as the height from the ground increases mainly due to the decrease in the friction produced by land terrain.
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: 25 kVAR 50 kVAR 100 kVAR 75 kVAR 25 kVAR 50 kVAR 100 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
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 = 5 kW and W2 = 25 kW W1 = 10 kW and W2 = 20 kW W1 = -10 kW and W2 = 40 kW W1 = -5 kW and W2 = 35 kW W1 = 5 kW and W2 = 25 kW W1 = 10 kW and W2 = 20 kW W1 = -10 kW and W2 = 40 kW ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Here,Cosφ = 0.397P = 30 kW = √3*V_L*I_L*cosφV_L*I_L = 30kW/(√3*0.397) = 43628.48 VAReadings of wattmeter W1 = V_L*I_L*cos(30+φ)Readings of wattmeter W2 = V_L*I_L*cos(30-φ)
MGVCL Exam Paper (30-07-2021 Shift 2) A single phase 240 V, 1 kW heater is connected across single phase 240 V, 50 Hz supply through an SCR. For firing angle delay of 90˚, calculate the power absorbed in the heater element. 250 W 300 W 275 W 225 W 250 W 300 W 275 W 225 W ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Resistance of heater, R = V²/PR = 57.6 ohmRMS value of voltage through controlled SCR = (Vm/2π)*(1 + cosα)= 120 VPower absorb by heater = Vrms²/R= 120²/57.6= 250 W
MGVCL Exam Paper (30-07-2021 Shift 2) What is the full form of UN in 'UN Human Rights Prize'? United Nations Uniform Nacional Unity Nation Uniformed Nations United Nations Uniform Nacional Unity Nation Uniformed Nations ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) Consider the following statements associated with Buchholz's relays.Statement 1: Buchholz's relay is a current operated device.Statement 2 : Buchholz's relay is placed between the transformer tank and the conservator. Statement 1 is FALSE and Statement 2 is TRUE Statement 1 is TRUE and Statement 2 is FALSE Both Statement 1 and Statement 2 are TRUE Both Statement 1 and Statement 2 are FALSE Statement 1 is FALSE and Statement 2 is TRUE Statement 1 is TRUE and Statement 2 is FALSE Both Statement 1 and Statement 2 are TRUE Both Statement 1 and Statement 2 are FALSE ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Buchholz relay is gas operated relay.It will operate when internal fault occurs in transformer.It is placed between tank to main conservator.It has two contacts trip and alarm.Use of Buchholz relay in distribution transformer is not economical.
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