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The armature of D.C. generator is laminated to

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The constant of a given energy meter is 500 revolution/kWh. At the test 4.4 kW full load, meter completes 50 revolutions in 86 seconds. The percentage error of the meter is (a) –4.86% (b) 4.86% (c) 2.0% (d) 3.0%

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0 answers 31 views

A single phase energy meter has a constant of 1200 revolution/kWh. When a load of 200 W is connected, the disc rotates at 4.2 revolutions per min. If the load is on for 10 hours, the meter records an excess of   (a) 0.1 kWh (b) 0.2 kWh (c) 1.0 kWh (d) 2.0 kWh 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
0 answers 31 views

A meter whose constant is 600 revolutions/kWh makes 5 revolutions in 20 seconds. Calculate the load in kW. (1) 0.5 kW (2) 1 kW (3) 1.5 kW (4) 2 kW  

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 25 views

A d.c. ampere-hour meter is rated at 5A, 250 V. The declared constant is 5 A sec/revolution. The constant in revolution/kwh will be (a) 2880 (b) 2680 (c) 2480 (d) 2280

asked May 25, 2018 in Electrical Measurements and Instrumentation by Shimroz123
1 answer 16 views

A 400 V, 15 kW, 4-pole, 50 Hz, Y-connected induction motor has full load slip of 4%. The output torque of the machine at full load is  (A) 1.66 Nm (B) 95.50 Nm (C) 99.47 Nm (D) 624.73 Nm

asked May 17, 2018 in Induction Machine by Shimroz123
1 answer 148 views

A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is

asked May 3, 2018 in Electric Power Transmission by Shimroz123
1 answer 17 views

A single-phase, 50 kVA, 250 V/500 V two winding transformer has an efficiency of 95% at full load, unity power factor. If it is re-configured as a 500 V/750 V auto-transformer, its efficiency at its new rated load at unity power factor will be  (A) 95.752% (B) 97.851% (C) 98.276% (D) 99.241%

asked May 17, 2018 in Transformer by Shimroz123
0 answers 58 views

An energy meter has a constant of 600 rev/kWh. If the meter makes 10 revolutions in 20 s, what is the load in kW?  (A) 0.75 kW (B) 1.5 kW (C) 3 kW (D) 6 kW 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 15 views

What is the maximum value of a load which consume 500 KWh per day at a load factor of 0.40, if the consumer increases the load factor of 0.50 without increasing the maximum demand? 

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 39 views

A generating station has a maximum demand of 500 MW. The annual load factor is 50 percent. The energy generated per annum will be: A) 2.19 x 106 MWhr B) 600 MWhr C) 250 MWhr D) 7.50 x 106 MWhr

asked Jun 17, 2018 in Electric Power Generation by Shimroz123
1 answer 17 views

A 50 kW dc shunt is loaded to draw rated armature current at any given speed. When driven  (i) at half the rated speed by armature voltage control and (ii) at 1.5 times the rated speed by field control, the respective output powers delivered by the motor are approximately. (A) 25 kW in (i) and 75 kW in (ii) (B) 25 kW in (i) and 50 kW in (ii) (C) 50 kW in (i) and 75 kW in (ii) (D) 50 kW in (i) and 50 kW in (ii)

asked May 17, 2018 in DC machine by Shimroz123
1 answer 63 views

The inertia constant of a 100 MVA, 11 kV water wheel generator is 4. The energy stored in the rotor at the synchronous speed is: A) 400 Mega Joule B) 400 Kilo Joule C) 25 Mega Joule D) 25 Kilo Joule

asked Jun 4, 2018 in Power system by Shimroz123
1 answer 42 views

A 50 Hz, 4-pole, 500 MVA, 22 kV turbo-generator is delivering rated megavolt amperes at 0.8 power factor. Suddenly a fault occurs reducing in electric power output by 40%. Neglect losses and assume constant power input to the shaft. The accelerating torque in the generator in MNm at the time of fault will be  (A) 1.528 (B) 1.018 (C) 0.848 (D) 0.509

asked May 25, 2018 in Power system by Shimroz123
1 answer 16 views

The meter constant of a single-phase 230 V induction watt hour meter is 400 revolutions per kWh. The speed of the meter disc for a current of 10 A of 0.9 pf lagging will be

asked Apr 23, 2018 in Electrical Engineering by Shimroz123
1 answer 80 views

The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 , V 57 Hz supply is  (A) 58.5 A (B) 45.0 A (C) 42.7 A (D) 55.6 A

asked May 17, 2018 in Electrical Machine by Shimroz123
1 answer 37 views

A 150 kW electric motor has an efficiency of 92 %, when it operates at full load. Calculate the losses in the machine.  (A) 92 kW (B) 150 kW (C) 163 kW (D) 13 kW 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 19 views

The full scale range of PMMC voltmeter is 100 V and its sensitivity is 1000 Ω/V. If the meter reads 50 V, the current through the voltmeter is (A) 0.05 mA (B) 0.5 mA (C) 5 mA (D) 50 mA 

asked Jun 4, 2018 in Electrical Measurements and Instrumentation by Shimroz123
1 answer 28 views

 A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
1 answer 19 views

A 200 V, 5 A d.c. energy meter is tested at its marked ratings. The resistance of the pressure circuit is 8000 Ω and that of current coil is 0.1 Ω. The power consumed when testing the meter with phantom loading with current circuit excited by a 6 V battery is (A) 2.5 W (B) 5 W (C) 32.5 W (D) 35 W

asked Apr 28, 2018 in Electrical Measurements and Instrumentation by Shimroz123
1 answer 15 views

In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is :

asked Apr 29, 2018 in Electrical Machine by Shimroz123
1 answer 32 views

A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for

asked Apr 29, 2018 in Electrical Machine by Shimroz123
1 answer 28 views

A two -winding single phase transformer has a voltage regulation of 4.5% at full - load and unity power -factor. At full -load and 0.80 lagging power-factor, the voltage regulation will be: (A) 4.5% (B) less than 4.5% (C) more than 4.5% (D) none of the above

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 21 views

A dc shunt motor runs at 500 r.p.m at 220 V. A resistance of 4.5 Ω is added in series with the armature for speed control. The armature resistance is 0.5 ohms. The current to stall the motor will be (1) 44 A (2) 50 A (3) 44.4 A (4) 60 A  

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
1 answer 35 views

The corona loss in a 50 Hz system is 0.25 kW/ph/km. At a frequency of 60 Hz, the corona loss would be   (a) 0.30 kW/ph/km (b) 0.36 kW/ph/km (c) 028 kW/ph/km (d) 0.21 kW/ph/km

asked May 13, 2018 in Power system by Shimroz123
1 answer 62 views

The corona loss of a 3-phase transmission line is 100 kW at 60 kV/phase and 25 kW at 50 kV/phase. The disruptive critical voltage is (A) 40 kV (B) 43.6 kV (C) 49.6 kV (D) 50 kV

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 29 views

The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is 1200 rev/kWh. Power consumption in the load is (A) 1.2 kW (B) 1 kW (C) 600 W (D) 500 W

asked Apr 25, 2018 in Instrumentation and control by Shimroz123
1 answer 13 views

A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is  (A) 50.0% (B) 70.7% (C) 141.4% (D) 200.0%

asked May 17, 2018 in Transformer by Shimroz123
1 answer 29 views

A 3 phase, 400 volts, 50 Hz, 100 kW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of: (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

asked Apr 11, 2018 in Computer Engineering by Shimroz123
0 answers 15 views

A 50 Hz, 3—phase induction motor has a full load speed of 1440 rpm. The number of poles of the motor is:   (A)4 (8)6 (0)12  (D)8

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
1 answer 52 views

The corona loss on a particular system at 50 Hz is 1 kw/phase per km. The corona loss on the same system with supply frequency 25 Hz will be?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 15 views

A two conductor 1 - pi line operates at 50 Hz.The diameter of each conductor is 4 cm and are spaced 6 m apart. What is the capacitive susceptance to neutral per km?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 117 views

The maximum demand of consumer is 2 kW and his daily energy consumption is 20 units. Its Load Factor is (1) 10.15% (2) 41.6 % (3) 50 % (4) 60% 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 40 views

If an energy meter disc makes 10 revolutions in 100 seconds when a load of 450W is connected to it, the meter constant in revolutions per kWh is  A) 1000 B) 500 C) 1600 D) 800

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
1 answer 137 views

A 3-phase, 11 kv, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. The capacitance perphase of the capacitor in micro-farads is?

asked Mar 27, 2018 in Power system by Shimroz123
0 answers 11 views

A 3-phase, 50 Hz, 500 V induction motor develops 20 hp at slip of 5%. Mechanical losses are 1 hp, and stator loss is 1 kW. The efficiency will be   (a) 95.3% (b) 90.5% (c) 91.3% (d) 85.3% 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
0 answers 19 views

A 10 kW electric motor drives a vehicle at an average speed of 50 Km/h. Ten, 12 V, 100A-h batteries supply the motor, the maximum distance that the vehicle may travel before the batteries must be recharged, will be : (A) 30 Km (B) 45 Km (C) 60 Km (D) 80 Km

asked Mar 31, 2018 in Electrical Engineering by Shimroz123
0 answers 24 views

What is the energy stored in the magnetic field at a solenoid of 40 cm long and 4 cm diameter wound with 100 turns of wire carrying a current at 20A?  (A) 0.705 Joule (B) 0.789 Joule (C) 0.587 Joule (D) 0.658 Joule 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 23 views

A current of 4 amperes flowing for 45 minutes deposits 1.062 gm of metal at cathode. Calculate the equivalent weight of the metal. (Given 1 Faraday = 96500 C)

asked Sep 3, 2018 by Shimroz123
0 answers 24 views

A single phase 230 V/ 150 V , 1 kVA, 50 Hz transformer is supplied by 230 V AC supply. Find the full load primary and secondary current. 

asked Sep 1, 2018 by Quiz
1 answer 63 views

A consumer consumes. 600 kWh per day at a load factor of 0.40. If the consumer increases the load factor of 0.70 without increasing the maximum demand, what is the consumption of energy in kWh?

asked Mar 27, 2018 in Power system by Shimroz123
1 answer 15 views

In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are?

asked Mar 19, 2018 in Transformer by Shimroz123
1 answer 41 views

A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

asked Apr 29, 2018 in Power Electronics by Shimroz123
1 answer 24 views

A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

asked Apr 28, 2018 in Power Electronics by Shimroz123
1 answer 40 views

Two waves have frequency of 500 Hz. One is set at its maximum value whereas the other at zero. The phase angle between them will be

asked Apr 26, 2018 in Electrical Measurements and Instrumentation by Shimroz123
1 answer 13 views

The no load speed of a d.c. shunt motor is 1140 rpm. At full load, the armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in rpm will be: (A) 1080 (B) 1203 (C) 1000 (D) 1200

asked Apr 11, 2018 in Computer Engineering by Shimroz123
0 answers 19 views

The efficiency of a transformer at full load 0.8 p.f lagging is 90%. Its efficiency at full load 0.8 p.f leading will be (1) Less than 90% (2) More than 90% (3) 90% (4) None of these 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 22 views

The usual value of slip of a 3Φ induction motor at full load is about:  (A) 0.05 (B) 0.1 (C) 0.3 (D) 0.8 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 55 views

Which meter is suitable for the measurement of 10 mV at 50 MHz ?   (a) Moving iron voltmeter (b) CRO (c) Electrostatic voltmeter (d) VTVM

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 20 views

At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of service, the load power factor becomes (A) 0.85 (B) 1.00 (C) 0.80 lag (D) 0.90 lag

asked May 25, 2018 in Power system by Shimroz123

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