Which of the following is not an Operating System?
If the load p.f. is 0.866, then the average p.f. the v-bank is
answered May 13, 2018 by Shimroz123
If the load p.f. is 0.866, then the average p.f. the v-bank is 0.75
The efficiency of a transformer at full load 0.8 p.f lagging is 90%. Its efficiency at full load 0.8 p.f...
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
In a 3-phase half-wave rectifier, if per phase input is 200 V, then the average output voltage is
In a 3-phase half-wave rectifier, if per phase input is 200 V, then the average output voltage is (a) 233.91 V (b) 116.95V (c) 202.56 V (d) 101.28V
If current is I and voltage is V, then power P is equal to
A 220 V dc machine has an armature resistance o f 1-ohm. If the full load current is 20A, the difference...
A 220 V dc machine has an armature resistance o f 1-ohm. If the full load current is 20A, the difference in the induced voltage when the machine is running as a motor, and as a generator is
If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by?
asked Mar 20, 2018 in DC generator by Shimroz123
induced
The voltage regulation of an alternator having 0.75 leading p.f. load, no-load induced e.m.f. of 2400V and ...
The voltage regulation of an alternator having 0.75 leading p.f. load, no-load induced e.m.f. of 2400V and rated terminal voltage of 3000V is ————————————— A) 20% B) —20% C) 150 D) -26.7
A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m...
A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?
When The dc converter in figure shown has a resistance load of R = 10 Ω and the input voltage is Vs 220 V the converter switch remains on, its voltage drop is Vo -2 V. The chopping frequency is fI K sW Vs If the duty cycle is 50%, determine: (a) the average output voltage V (b) the RMS output voltage Vo (c) the converter efficiency (d) the effective input resistance of the converter
asked Apr 26 by Hussein
If the range of an analog transducer is 0 to 10 V, then for a resolution of 5 mV, the bits of ADC will be _____.
asked May 29, 2018 in Transducers and sensors by Shimroz123
What should be kVA rating of each transformer in V-V bank when three phase balanced load is
What should be kVA rating of each transformer in V-V bank when three phase balanced load is 40 kVA ? (A) 19 (B) 28 (C) 37 (D) 23
If the supply frequency of a 3-phase induction motor is 'f', then frequency of rotor emf at motor slip 's' will be
If the supply frequency of a 3-phase induction motor is 'f', then frequency of rotor emf at motor slip 's' will be (a) sf (b) (1 – s)f (c) f/s (d) None of these
A diesel power station spends 0.25 kg/kWh fuel. If the calorific value is 10,000 kcal/kg then overall efficiency...
A diesel power station spends 0.25 kg/kWh fuel. If the calorific value is 10,000 kcal/kg then overall efficiency of the power station will be (a) 25% (b) 30% (c) 34.4% (d) 100%
The per unit impedance of a circuit element is 0.30. If the base kV and base MVA are halved, then the new...
The per unit impedance of a circuit element is 0.30. If the base kV and base MVA are halved, then the new value of the per unit impedance of the circuit element will be: (A) 0.3 (B) 0.6 (C) 0.003 (D) 0.006
If the characteristics equation of a closed loop system is s2+2s+2=0, then the system is...
If the characteristics equation of a closed loop system is s2+2s+2=0, then the system is (A) Over damped (B) Critically damped (C) Under damped (D) Undamped
A 500 MW, 3-phase, Y-connected synchronous generator has a rated voltage of 21.5 kV at 0.85 p.f. The line
A 500 MW, 3-phase, Y-connected synchronous generator has a rated voltage of 21.5 kV at 0.85 p.f. The line current when operating at full load rated conditions will be (A) 13.43 kA (B) 15.79 kA (C) 23.25 kA (D) 27.36 kA
asked May 17, 2018 in Synchronous machine by Shimroz123
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm...
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be?
A thyristor is triggered by a pulse train of 5 kHz. The duty ratio is 0.4. If the allowable average power is 100 W,
A thyristor is triggered by a pulse train of 5 kHz. The duty ratio is 0.4. If the allowable average power is 100 W, the maximum allowable gate drive power will be
A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is
A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is?
asked Mar 27, 2018 in Power system by Shimroz123
The maximum flux in a transformer is φm when primary voltage is V and the frequency is f. If the primary
The maximum flux in a transformer is φm when primary voltage is V and the frequency is f. If the primary voltage is 2 V and frequency is f/2, the flux will be (a) 4 φm (b) 0.25 φm (c) φm (d) 0.5 φm
asked May 25, 2018 in Transformer by Shimroz123
When the SCR conducts, the forward voltage drop will (a) 0.7 V at all load current (b) 2 to 2.5 V at all load...
When the SCR conducts, the forward voltage drop will (a) 0.7 V at all load current (b) 2 to 2.5 V at all load current (c) increases slightly with load current (d) remains constant with load current
If the feedback factor of an amplifier is 0.1 and its gain without feedback is 40, then its gain with feedback is
If the feedback factor of an amplifier is 0.1 and its gain without feedback is 40, then its gain with feedback is (a) – 13.3 (b) 200 (c) 8 (d) 10
asked May 25, 2018 in Amplifier by Shimroz123
If p is a pointer to an integer and t is a pointer to a character then sizeof(p) will be
If p is a pointer to an integer and t is a pointer to a character then sizeof(p) will be (1) same as that of sizeof(t) (2) greater than that of sizeof(t) (3) less than that of sizeof(t) (4) none of these
In a R-L series circuit the power factor P.F. is _________.
asked Mar 31, 2018 in Electrical Engineering by Shimroz123
If α=0.995, IE=10 mA and ICO=0.5 mA, then ICEO will be...
If α=0.995, IE=10 mA and ICO=0.5 mA, then ICEO will be (A) 100 μA (B) 25 μA (C) 10.1 μA (D) 10.5 μA
In a power generating station the Demand Factor and Load Factor are 0.5 and 0.2, respectively. If the...
In a power generating station the Demand Factor and Load Factor are 0.5 and 0.2, respectively. If the connected load is 400 MW, the average demand is (A) 40 MW (B) 100 MW (C) 140 MW (D) 280 MW
The peak value of a sine wave is 200 V. Its average value is?
If the no load voltage of a certain generator is 220V and the rated load voltage is 200V, then the voltage regulation is: a. 1% b. 10% c. 20V d. 9%
asked Sep 1, 2018 by Shimroz123
The power in a 3-phase load is measured by two watt meters. If one watt meter reads zero, then the load
The power in a 3-phase load is measured by two watt meters. If one watt meter reads zero, then the load power factor is (A) Zero (B) 0.5 (C ) 0.866 (D) unity
asked Jun 4, 2018 in Electrical Measurements and Instrumentation by Shimroz123
If a voltage-controlled bus is treated as load bus, then which one of the following limits would be
If a voltage-controlled bus is treated as load bus, then which one of the following limits would be violated? (a) Active power (b) Reactive power (c) Voltage (d) Phase angle
If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then?
asked Mar 20, 2018 in Synchronous machine by Shimroz123
synchronous
synchronised
negligible
If a variable can take only integer values from 0 to n, where n is a constant integer, then variable can be ...
If a variable can take only integer values from 0 to n, where n is a constant integer, then variable can be represented as a bit-field whose width is the integral part of (assume base 2) (1) log(n) +1 (2) log(n + 1) + 1 (3) log(n – 1) + 1 (4) none of these
The following formula is correct: (A) Load factor=Average load for a period/ Peak load for the same period
The following formula is correct: (A) Load factor=Average load for a period/ Peak load for the same period (B) Load factor=Average load for a period x Peak load for the same period (C) Load factor=Average load for a period + Peak load for the same period (D) All of the above
If a DC voltmeter is made from an ammeter having a fed of 100μA then its sensitivity (in KΩ/V) will be
What's difference between ampere and ampere hour.? If my battery bank is 48v 300Ah, what may be the ampere?
asked Sep 30, 2018 in Battery by anonymous
A balanced Delta connected load supplied with 440 V 50 Hz three phase AC supply has R=10 Ohm and L=0.6 mH in is each arm. Calculate line and phase current, active power.
asked Aug 12, 2018 in Basic electrical and electronics engineering by Quiz
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
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
The following is correct : (A) P = V x I (B) P = I ² x R (C) P = V ² / R (D) All of the above
asked May 8, 2018 in Electrical Engineering by Shimroz123
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...
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
To Charge a 120 V battery from a 600 V DC source using a DC chopper, The average battery current should...
To Charge a 120 V battery from a 600 V DC source using a DC chopper, The average battery current should be 20 A, with a peak to peak ripple of 2 A. If the chopper frequency is 200 Hz, calculate the duty cycle. (A) 0.2 (B) 0.1 (C) 0.5 (D) 0.6
A 1000 watts heater is connected to a 240 V AC Supply. Then the current drawn by the heater is
The maximum possible power of a 3-phase synchronous motor with synchronous reactance 0.8 p.u. connected
The maximum possible power of a 3-phase synchronous motor with synchronous reactance 0.8 p.u. connected to a bus-bar of 1.0 p.u. and excitation adjusted to 1.2 p.u. is (A) 0.5 p.u. (B) 0.96 p.u. (C) 1.5 p.u. (D) 1.8 p.u.
If the inertia constant H of a machine of 200 MVA is 2 p.u., its value corresponding to 400 MVA will be
If the inertia constant H of a machine of 200 MVA is 2 p.u., its value corresponding to 400 MVA will be (a) 4 p.u. (b) 2 p.u. (c) 1.0 p.u. (d) 0.5 p.u.
The average value of a 12 V peak sine wave over one complete cycle is?
The average value of a 12 V peak sine wave over one complete cycle is? A.0 V B.1.27 V C.7.64 V D.6.37 V
asked May 15, 2018 in Basic concepts by Shimroz123
When 7/0.029 V.I.R cable is carrying 20 A, a drop of 1 V occurs every 12 m. The voltage drop in a 100 m run of...
When 7/0.029 V.I.R cable is carrying 20 A, a drop of 1 V occurs every 12 m. The voltage drop in a 100 m run of this cable when it is carrying 10 A is nearly (a) 4.2 V (b) 3.2 V (c) 1.2 V (d) 0.42 V
If 1 ampere current is flowing through a 100 mH coil, then energy stored in the coil is
If 1 ampere current is flowing through a 100 mH coil, then energy stored in the coil is (a) 0.05 Joules (b) 0.5 Joules (c) 5.0 Joules (d) None of these
The phase sequence of a 3 phase alternator is RBY. If the direction of rotation of field is reversed, then...
The phase sequence of a 3 phase alternator is RBY. If the direction of rotation of field is reversed, then which of the following can be the phase sequence ? (A) RBY (B) BYR (C) BRY (D) YRB
A series generator is supplying power to DC bus bar. If the prime mover fails, then the machine will operate...
A series generator is supplying power to DC bus bar. If the prime mover fails, then the machine will operate as (A) DC series motor rotating in the same direction (B) DC series motor rotating in the opposite direction (C) DC series generator rotating in the same direction (D) Machine will stop
The step angle of the stepper motor is 2.5°. If the stepping frequency is 3600 pulses per second, then the ...
The step angle of the stepper motor is 2.5°. If the stepping frequency is 3600 pulses per second, then the shaft speed will be (a) 144 rps (b) 3600 rps (c) 25 rps (d) 2.5 rps
In case of four pole, lap wound machine if the air gap under each pole is the same, then what will be the...
In case of four pole, lap wound machine if the air gap under each pole is the same, then what will be the result? (A) There will be reduced eddy currents (B) There will be reduced hysteresis loss (C) Current in each path will not be the same (D) It will result in higher terminal voltage