Can you help by answering this question?

In phase shift keying the power required is

16 views
in Electrical Engineering by
An alternator is delivering rated current at rated voltage and 0.8 power-factor lagging. For delivering rated current at rated voltage and 0.8 poWer—factor leading, the required excitation will be: 

(A) less  (B) more (C) more or less (D) the same

1 Answer

0 votes
by

An alternator is delivering rated current at rated voltage and 0.8 power -factor lagging. For delivering rated current at rated voltage and 0.8 power -factor leading, the required excitation will be: more 

Related questions

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 33 views

A 400 V, 50 Hz 30 hp, three-phase induction motor is drawing 50 A current at 0.8 power factor lagging. The stator and rotor copper losses are 1.5 kW and 900 W respectively. The friction and windage losses are 1050 W and the core losses are 1200 W. The air-gap power of the motor will be (A) 23.06 kW (B) 24.11 kW (C) 25.01 kW (D) 26.21 kW

asked May 17, 2018 in Electrical Machine by Shimroz123
1 answer 83 views

The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?

asked Mar 25, 2018 in Electrical Engineering by Shimroz123
1 answer 44 views

In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

asked Mar 18, 2018 in Alternator by Shimroz123
0 answers 19 views

A three phase transmission line delivers a load of 5 MW at 0.8 power factor lagging. Resistance of each conductor is 0.5 ohm / km. Receiving end voltage is 33 kV. If the line loss is not to exceed 10%, determine the length of the line.  (A) 7 km (B) 27.9 km (C) 56.8 km (D) 13.9 km

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 8 views

 When alternator excitation increases and machine is operating at lagging power factor then (A) Armature current increases (B) Armature current decreases (C) Armature current remains unchanged (D) Armature voltage remains unchanged

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
1 answer 18 views

A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is  (A) magnetizing (B) demagnetizing (C) cross-magnetizing (D) ineffective

asked May 17, 2018 in Synchronous machine by Shimroz123
1 answer 31 views

A alternator is delivering power to a balanced load at unit power factor. The phase angle between the line voltage and the line current is? (A) 90° (B) 60° (C) 30° (D) 0° 

asked Apr 23, 2018 in Electrical Engineering by Shimroz123
0 answers 12 views

An induction motor operating at 0.8 pf lagging is consuming 300 kW. A zero real power consuming synchronous motor is connected across the induction motor to raise the pf to 0.92 lagging. The reactive power drawn by the synchronous motor is a. - 352 kVAR b. - 225 kVAR c. - 127.8 kVAR d. - 97.2 kVAR

asked May 24, 2018 in Induction Machine by Shimroz123
0 answers 88 views

A single phase 60 Hz generator supplies an inductive load of 4500kW at a power factor of 0.80 lagging by means of a 20 km long overhead transmission line. The line resistance and inductance are 0.0195 ohm and 0.60 mH per km. The voltage at the receiving end is required to be kept constant at 10.2 kV. Find the voltage regulation of the line.  (A) 12.59% (B) 16.34% (C) 32.68% (D) 41.15% 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 17 views

A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased  1. The power factor decreases upto a certain value of field current and thereafter it increases.  2. The armature current increases upto a certain value of field current and thereafter it decreases.  3. The power factor increases upto a certain value ... field current and thereafter it, increases.  From these, the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

asked May 13, 2018 in Electrical Engineering by Shimroz123
0 answers 45 views

For a balanced three phase star connected load for which line voltage is 230V and per phase resistance and reactance is 6 Ohm and 8 Ohm respectively. Calculate: 1) phase voltage 2) line current 3) power factor 4) total power absorbed

asked Aug 12, 2018 in Basic electrical and electronics engineering by Quiz
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
1 answer 42 views

 An 8-pole alternator runs at 750 rpm and supplies power to a 6-pole induction motor which has a full load slip of 3 percent. The full load speed of the induction motor will be: A) 1000 rpm B) 920 rpm C) 950 rpm D) 970 rpm

asked Jun 4, 2018 in Alternator by Shimroz123
0 answers 21 views

A synchronous motor is delivering 80% of its rated output and is operating at UPF. If its excitation is increased, then  (1) the output delivered gets increased (2) its pf becomes lagging (3) the output delivered gets decreased (4) its pf becomes leading

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 24 views

In a synchronous generator delivering lagging power factor load  (1) the excitation emf leads terminal voltage by the power angle (2) the excitation emf lags terminal voltage by the power angle (3) excitation emf leads the terminal voltage by the power factor angle (4) excitation emf lags the terminal voltage by the power factor angle

asked Apr 29, 2018 in Electrical Machine by Shimroz123
0 answers 13 views

The voltage regulation for 0.95 lead pf is zero for an alternator. If so, the voltage regulation for 0.9 lead pf with all other conditions remaining same will be (A) Positive (B) Negative (C) Zero (D) Insufficient data

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
0 answers 12 views

What is the pitch factor of a 4 pole alternator having 36 slots and a coil span of 1 to 8?  (A) 140° (B) 80° (C) 20° (D) 40°

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 10 views

For the given voltage and current, the value of voltage regulation of a line for lagging loads with decrease in power factor (a) decreases (b) increases (c) remains same (d) either (a) or (c) 

asked May 25, 2018 in Electrical Engineering by Shimroz123
2 answers 52 views

If resistance is 8 Ohm and current is 16 ampere then what will be the voltage and power?

asked Oct 21, 2017 in Electrical Engineering by Quiz
0 answers 13 views

 A single phase, 2000V alternator has armature resistance and reactance of 0.8 ohm and 4.94 ohm respectively. The voltage regulation of the alternator at 100A, 0.8 leading pf is (A) 7% (B) - 8.9% (C) - 6.3% (D) 0%

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
0 answers 16 views

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

asked Apr 9, 2018 in Electronics Engineering by Shimroz123
0 answers 30 views

A system function has a pole at s=0 and a zero at s= -1. The constant multiplier is unity. For an excitation cos(t), What is the steady-state response?  (A) √2sin(t+450) (B) √2sin(t-450) (C) sin(t-450) (D) Sin(t) 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 27 views

A 12 -pole, 440 V, 50 Hz, 3 -phase synchronous motor takes a line current of 100 A at 0.8 pf leading. Neglecting losses, the torque developed will be

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
0 answers 9 views

 At dead short circuit at terminals of an alternator, the current 'I' is at (A) ZPF lag (B) ZPF lead (C) Unity power factor (D) 0.8 power factor lag

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
1 answer 18 views

At which power factor alternator is said to be overexcited?

asked Mar 18, 2018 in Alternator by Shimroz123
1 answer 16 views

The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu from a lagging load are 45o and 15o, respectively. The direct axis and quadrature axis currents, respectively, are (A) 0.5 pu, 0.866 pu (B) 0.866 pu, 0.5 pu (C) 0.707 pu, 0.707 pu (D) 0.5 pu, 0.5 pu

asked Apr 28, 2018 in Electrical Machine by Shimroz123
0 answers 20 views

An alternator is connected to a bus. For a symmetrical fault at the bus, the fault level is 60 MVA. If another alternator is connected to the same bus, the new fault level will be (1) 120 MVA (2) 60 MVA (3) 30 MVA (4) 15 MVA 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
1 answer 18 views

Capacitors for power factor correction are rated in?

asked Mar 25, 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
1 answer 43 views

For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is

asked Apr 30, 2018 in Electrical Engineering by Shimroz123
1 answer 26 views

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
0 answers 308 views

Two generating stations G1 and G2 of ratings 10 MVA and 8 MVA respectively are linked by a line rated at 5 MVA, 0.1 Pu reactance. Each station has a reactance of 0.5 pu. If the base MVA is 10 MVA, short-circuit MVA of G1 is

asked May 24, 2018 in Power system by Shimroz123
0 answers 21 views

A dc shunt generator has a speed of 800 rpm when delivering 20 A to the load at the terminal voltage of 220V. If the same machine is run as a motor it takes a line current of 20A from 220V supply. The speed of the machine (in rpm) will be:  (A) 800 (B) more than 800 (C) less than 800 (D) none of the above

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
0 answers 48 views

A 200 V, 50 Hz inductive circuit takes a current of 10 A at 30 degree lagging pf, what is the inductive reactance of the circuit?  (A) 17.8 Ω (B) 100 Ω (C) 178 Ω (D) 10 Ω 

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

An unsaturated dc shunt motor runs at its rated speed when rated voltage is applied to it. If the supply voltage to the motor is reduced by 25%, the speed of the motor  (a) Increases by 25% (b) Remains the same (c) Decreases by 25% (d) Decrease only slightly by an amount less than 25% 

asked May 13, 2018 in Power Electronics by Shimroz123
0 answers 18 views

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 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 97 views

The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?

asked Mar 25, 2018 in Electrical Engineering by Shimroz123
1 answer 19 views

A motor which can conveniently be operated at lagging as well as leading power factors is the:   (A) squirrel cage induction motor (C) synchronous motor (B) wound rotor induction motor (D) DC shunt motor

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
0 answers 32 views

In a hydel power station, the number of poles of an alternator is 24. At what rpm the alternator must be driven to produce 50 Hz voltage?

asked Apr 3, 2018 in Lesson 2 Generation, Transmission and Distribution of Electric Power an Overview by Shimroz123
1 answer 13 views

If the lagging power factor of the load decreases, the line losses will (A) Decrease (B) Increase (C) Flrst decrease and then Increase (D) Remain same

asked May 12, 2018 in Electrical Engineering by Shimroz123
1 answer 20 views

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

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 24 views

The power factor of an alternator depends on?

asked Mar 18, 2018 in Alternator by Shimroz123
1 answer 17 views

A 3-phase induction motor is driving a constant torque load at rated voltage and frequency. If both voltage and frequency are halved, following statements relate to the new condition if stator resistance, leakage reactance and core loss are ignored  1. The difference between synchronous speed and actual speed remains same 2. The airgap flux remains same 3. The ... . slip remains same Among the above, current statements are  (A) All (B) 1, 2 and 3 (C) 2, 3 and 4 (D) 1 and 4

asked May 18, 2018 in Induction Machine by Shimroz123
1 answer 7 views

Explain lagging quantity and leading quantity, explain this concept with voltage and current waveform

asked Sep 7, 2018 by Shimroz123
0 answers 95 views

An auto transformer having a transformation ratio of 0.8 supplies a load of 10 kW. The power transferred inductively from the primary to secondary is (a) 2 kW (b) 4 kW (c) 8 kW (d) 10 kW 

asked May 25, 2018 in Autotransformer by Shimroz123
1 answer 118 views

A 60 Hz, 4 pole turbo generator rated 100 MVA, 13.8 KV has an inertia constant of 10 MJ/MVA. Find the stored energy in the rotor at synchronous speed.  (A) 10 MJ (B) 100 J (C) 1000 J (D) 1000 MJ 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 51 views

A 8 pole alternator rotates at 750 r.p.m. Its frequency is

asked May 15, 2018 in Alternator by Shimroz123
1 answer 8 views

A dc series motor driving and electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to  (A) 0.75 p.u (B) 0.5 p.u (C) 0.25 p.u (D) 0.125 p.u

asked May 18, 2018 in DC motor by Shimroz123

Welcome to electronics2electrical.com here you can ask questions related to electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc.
Be respectful to all the members. Do not copy and paste the answers from other websites which have copyright content. While asking question give full details about it.

Categories

Most popular tags

power motor dc circuit transformer voltage current used system phase resistance factor synchronous load ac energy induction electric generator series frequency between speed capacitor use electrical meter line difference control type mosfet transmission magnetic plant high single instrument bjt unit source advantages function diode and machine winding field define torque parallel amplifier supply shunt thyristor motors electricity arduino maximum time relay armature problem value on transformers types coil diagram state flow ratio material three formula starting direction theorem method emf operating efficiency digital wave microprocessor test instruments inductance loss measure operation connected signal low applications effect single-phase network temperature working constant losses different law wattmeter measuring compare controlled breaker drive device logic rc full switch flux wire resistivity disadvantages free of materials machines angle force converter conductor transistor gain open protection scr core measurement number bridge principle generators reactance circuits negative the friction iron loop short pole battery conservation steam resistors hysteresis computer using analog lines secondary station gate a rectifier inverter linear induced relays nuclear capacitance basic characteristics design direct work rotor electronics ammeter forces diesel damping rlc connection factors capacitors minimum insulation moving regulation running self systems air fault range main stability quality starter igbt eddy alternator ideal rl average 3-phase plants arc thermal error fuzzy biasing dielectric pressure balanced superposition errors copper rotation feedback impedance measured electronic electrons charge inductive transfer explain start off back curve over solar is three-phase tariff locomotive peak bias zener engineering commutator surge conductors rating universal potentiometer density permanent mechanical transducer capacity memory adc excitation two fuse pure harmonics application semiconductor inductor internal pmmc reaction welding resonance traction permeability breakers rms designed electromagnetic si generation brushes switching capacitive shaded rate 1 distribution resistor methods delta star oscillator reluctance simplification algebra 8085 boolean weston dynamometer insulating strength installation definition fuel heating earth units

8,450 questions

7,047 answers

132 comments

3,084 users

...