Alternator Synchronous Generator To say Is Why ?

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alternator Synchronous At speed Rotate Is Says This one Synchronous Generator Says.
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Why Alternator is called Synchronous generator?

Description : Why Alternator is called Synchronous generator?

Last Answer : Because it rotates at a constant (i.e.synchronous speed ) no matter what the load on alternator is.For instance if its a 2 pole machine it will rotate at 3000 rpm to produce a frequency of 50 Hz in India.

77. type of generator are made use in wind turbines. a) Recreational generators b) Synchronous generator c) Asynchronous generator d) Alternator

Description : 77. type of generator are made use in wind turbines. a) Recreational generators b) Synchronous generator c) Asynchronous generator d) Alternator

Last Answer : Asynchronous generator

The cycles per second developed by the alternator aboard your vessel is determined by _____________. A. the speed of the engine driving the alternator B. the resistance applied to the field rheostat C. the synchronous speed of induction D. the adjustments made to the voltage regulator

Description : The cycles per second developed by the alternator aboard your vessel is determined by _____________. A. the speed of the engine driving the alternator B. the resistance applied to the field rheostat C. the synchronous speed of induction D. the adjustments made to the voltage regulator

Last Answer : Answer: A

What is meant by synchronous impedance of an Alternator?

Description : What is meant by synchronous impedance of an Alternator?

Last Answer : The combination of armature resistance and synchronous reactance is known as synchronous impedance

Derive the relationship between Synchronous speed (Ns) and frequency (f) of alternator.

Description : Derive the relationship between Synchronous speed (Ns) and frequency (f) of alternator.

Last Answer : Derivation of Relationship Between Synchronous speed (Ns) and Frequency (f) of Alternator: Let, Ns = rotor speed in rpm (synchronous speed) P = number of rotor poles f = frequency of emf in Hz ... complete cycle of emf is generated in the conductor as pair of poles passes it. Hence : 

The number of electrical degrees ‘passed through’ in one revolution of a 6-pole synchronous alternator is:

Description : The number of electrical degrees ‘passed through’ in one revolution of a 6-pole synchronous alternator is: A) 360 degree B) 720 degree C) 1080 degree D) 2160 degree

Last Answer : 1080

An open occurring within the field rheostat of an AC generator can be detected by short circuiting its terminals and observing a ____________. A. negative deflection of the wattmeter pointer B. positive deflection of the wattmeter pointer C. buildup of alternator voltage D. low, but constant alternator voltage

Description : An open occurring within the field rheostat of an AC generator can be detected by short circuiting its terminals and observing a ____________. A. negative deflection of the wattmeter pointer B. ... of the wattmeter pointer C. buildup of alternator voltage D. low, but constant alternator voltage

Last Answer : Answer: C

An alternator will fail to produce line voltage as a result of _____________. A. a closed circuit breaker B. oxidized slip rings C. improperly staggered brushes D. exciter generator failure

Description : An alternator will fail to produce line voltage as a result of _____________. A. a closed circuit breaker B. oxidized slip rings C. improperly staggered brushes D. exciter generator failure

Last Answer : Answer: D

When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming generator is approaching that of the bus B. frequency of the incoming alternator is less than that of the bus C. phase rotation of the incoming alternators is opposite to that of the bus D. terminal voltage of the incoming alternator is approaching that of the bus

Description : When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming ... the bus D. terminal voltage of the incoming alternator is approaching that of the bus

Last Answer : Answer: A

The purpose of the reverse power relay, provided on a ship's service alternator panel, is to trip the circuit in the event of ______________. A. main circuit overload B. high power transfer C. generator overspeeding D. alternator motorization

Description : The purpose of the reverse power relay, provided on a ship's service alternator panel, is to trip the circuit in the event of ______________. A. main circuit overload B. high power transfer C. generator overspeeding D. alternator motorization

Last Answer : Answer: D

In the illustration, if one of the devices labeled 'TURB' should fail the ___________. EL-0003 A. device labeled 'EXC' will drive the alternator B. device labeled 'BKR' for that alternator should automatically open because of the reverse power relay C. operator must open all the devices labeled 'BKRS' to reduce the load on the remaining turbo-alternator D. emergency generator should automatically start and be placed on line to supply emergency load centers

Description : In the illustration, if one of the devices labeled 'TURB' should fail the ___________. EL-0003 A. device labeled 'EXC' will drive the alternator B. device labeled 'BKR' for that ... -alternator D. emergency generator should automatically start and be placed on line to supply emergency load centers

Last Answer : Answer: B

Loss of or weak residual magnetism in an alternator or generator can be corrected for by _________________. A. running the rotor in the opposite direction for 5 minutes B. allowing the generator to run at 10% of normal speed for 5 minutes C. running the generator at normal speed with the field rheostat fully counterclockwise D. using a storage battery or battery charger to 'flash' the field

Description : Loss of or weak residual magnetism in an alternator or generator can be corrected for by _________________. A. running the rotor in the opposite direction for 5 minutes B. allowing the generator ... rheostat fully counterclockwise D. using a storage battery or battery charger to 'flash' the field

Last Answer : Answer: D

The standard method of controlling the output voltage of a 440 volt, 60 Hz, AC generator is accomplished by adjusting the ____________. A. prime mover speed droop B. number of poles C. alternator field excitation D. load on the alternator

Description : The standard method of controlling the output voltage of a 440 volt, 60 Hz, AC generator is accomplished by adjusting the ____________. A. prime mover speed droop B. number of poles C. alternator field excitation D. load on the alternator

Last Answer : Answer: C

The frequency of an AC generator is adjusted by means of the ____________. A. main alternator field rheostat B. exciter field rheostat C. prime mover governor control D. equalizing reactor

Description : The frequency of an AC generator is adjusted by means of the ____________. A. main alternator field rheostat B. exciter field rheostat C. prime mover governor control D. equalizing reactor

Last Answer : Answer: C

The output voltage of a 440 volt, 60 Hz AC generator is controlled by the ______________. A. load on the alternator B. load on the prime mover C. speed of the prime mover D. exciter output voltage

Description : The output voltage of a 440 volt, 60 Hz AC generator is controlled by the ______________. A. load on the alternator B. load on the prime mover C. speed of the prime mover D. exciter output voltage

Last Answer : Answer: D

An electrical device which employs a stationary armature and a rotating electromagnetic field is used aboard ship as a ____________. A. magnetic amplifier B. ship's service alternator C. three-wire DC generator D. saturable core reactor

Description : An electrical device which employs a stationary armature and a rotating electromagnetic field is used aboard ship as a ____________. A. magnetic amplifier B. ship's service alternator C. three-wire DC generator D. saturable core reactor

Last Answer : Answer: B

The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________. A. prime mover speed B. exciter output voltage C. load on the alternator D. number of poles

Description : The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________. A. prime mover speed B. exciter output voltage C. load on the alternator D. number of poles

Last Answer : Answer: B

Why AC generator is called Alternator?

Description : Why AC generator is called Alternator?

Last Answer : An alternator is such a machine which produces alternation electricity. It is a kind of generator which converts mechanical energy into alternating electrical energy.

State the difference between generator and alternator

Description : State the difference between generator and alternator

Last Answer : Generator and alternator are two devices, which converts mechanical energy into electrical energy. Both have the same principle of electromagnetic induction, the only difference is that their ... voltages but for low voltage output rotating armature and stationary magnetic field is used.

Induction generator a) can not work in isolation b) can work in isolation c) should work in parallel with synchronous generators d) any of the mentioned

Description : Induction generator a) can not work in isolation b) can work in isolation c) should work in parallel with synchronous generators d) any of the mentioned

Last Answer : Ans: C

If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ahead or behind its normal position as it rotates. This co A. hunting B. direct coupling C. peaking D. harmonic coupling

Description : If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ahead or behind ... as it rotates. This co A. hunting B. direct coupling C. peaking D. harmonic coupling

Last Answer : Answer: A

The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator

Description : The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator

Last Answer : Answer: C

The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor

Description : The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor

Last Answer : Answer: A

If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ahead or behind its normal position as it rotates. This hu A. amortisseur windings B. direct coupling C. increase governor speed droop D. decreasing governor speed droop

Description : If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ... windings B. direct coupling C. increase governor speed droop D. decreasing governor speed droop

Last Answer : Answer: A

The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Last Answer : Answer: C

In an AC synchronous motor electric propulsion plant, propeller speed is controlled by varying the _____________. A. prime mover speed B. electric coupling field strength C. number of energized main motor poles D. propulsion generator field strength

Description : In an AC synchronous motor electric propulsion plant, propeller speed is controlled by varying the _____________. A. prime mover speed B. electric coupling field strength C. number of energized main motor poles D. propulsion generator field strength

Last Answer : Answer: A

What is the difference between synchronous generator & asynchronous generator?

Description : What is the difference between synchronous generator & asynchronous generator?

Last Answer : In simple, synchronous generator supply’s both active and reactive power but asynchronous generator (induction generator) supply’s only active power and observes reactive power for magnetizing. This type of generators is used in windmills.

What Is The Difference Between Synchronous Generator & Asynchronous Generator?

Description : What Is The Difference Between Synchronous Generator & Asynchronous Generator?

Last Answer : In simple, synchronous generator supply’s both active and reactive power but asynchronous generator(induction generator) supply’s only active power and observe reactive power for magnetizing. This type of generators are used in windmills.

What is the difference between synchronous generator and asynchronous generator?

Description : What is the difference between synchronous generator and asynchronous generator?

Last Answer :  In simple, synchronous generator supplies’ both active and reactive power but asynchronous generator (induction generator) supply’s only active power and observe reactive power for magnetizing. This type of generators is used in windmills.

A booster is a (a) series wound generator (b) shunt wound generator (c) synchronous generator (d) none of the above

Description : A booster is a (a) series wound generator (b) shunt wound generator (c) synchronous generator (d) none of the above

Last Answer : (a) series wound generator

A booster is a (a) series wound generator (b) shunt wound generator (c) synchronous generator (d) none of the above

Description : A booster is a (a) series wound generator (b) shunt wound generator (c) synchronous generator (d) none of the above

Last Answer : (a) series wound generator

The active power of a synchronous generator can be varied mainly by

Description : The active power of a synchronous generator can be varied mainly by (a) changing field excitation (b) changing of prime mover speed (c) both (a) and (b) (d) none of the above

Last Answer : C

A hydraulic turbine having rated speed of 250 rpm is connected to a synchronous generator. In order to

Description : A hydraulic turbine having rated speed of 250 rpm is connected to a synchronous generator. In order to produce power at 50 Hz, the number of poles required in the generator are (A) 6 (B) 12 (C) 16 (D) 24

Last Answer : A hydraulic turbine having rated speed of 250 rpm is connected to a synchronous generator. In order to produce power at 50 Hz, the number of poles required in the generator are 24

A 100 MVA, 11 KV, 3-phase, 50 Hz, 8—pole synchronous generator has an inertia constant H equal to

Description : A 100 MVA, 11 KV, 3-phase, 50 Hz, 8—pole synchronous generator has an inertia constant H equal to 4 seconds. The stored energy in the rotor of the generator at synchronous speed will be  A) 100 MJ B) 400 MJ C) 800 MJ D) 12.5 MJ

Last Answer : 800

A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now

Description : A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.  ... left unaltered (D) the field current has to be reduced and fuel input left unaltered

Last Answer : A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.  the field current has to be reduced and fuel input left unaltered

A 500 MW, 3-phase, Y-connected synchronous generator has a rated voltage of 21.5 kV at 0.85 p.f. The line

Description : 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

Last Answer : 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 15.79 kA

A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction

Description : 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

Last Answer : A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is demagnetizing 

The angle δ in the swing equation of a synchronous generator is the

Description : The angle δ in the swing equation of a synchronous generator is the  (A) angle between stator voltage and current (B) angular displacement of the rotor with respect to the stator (C) angular ... (D) angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis

Last Answer : The angle δ in the swing equation of a synchronous generator is the angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis

For a fault at the terminals of a synchronous generator, the fault current is maximum for a

Description : For a fault at the terminals of a synchronous generator, the fault current is maximum for a  A) 3-phase fault B) 3-phase to ground fault C) Line to ground fault D) Line to line fault

Last Answer : C) Line to ground fault

A 500 MVA, 11 KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance

Description : A 500 MVA, 11 KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance on the base values of 100 MVA and 22 KV is  A) 0.16 B) 0.01 C) 4.0 D) 0.25

Last Answer : A 500 MVA, 11 KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance on the base values of 100 MVA and 22 KV is 0.01

In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load

Description : In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load  (A) The armature current increases and the power factor decreases  (B) The armature ... but is lagging  (D) The armature current decreases and the power factor increases and is leading

Last Answer : In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load The armature current decreases and the power factor increases and is leading

In a synchronous generator delivering lagging power factor load

Description : 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) ... by the power factor angle (4) excitation emf lags the terminal voltage by the power factor angle

Last Answer : In a synchronous generator delivering lagging power factor load the excitation emf leads terminal voltage by the power angle

The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu

Description : 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 ... pu, 0.5 pu (C) 0.707 pu, 0.707 pu (D) 0.5 pu, 0.5 pu

Last Answer : 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 0.866 pu, 0.5 pu

The armature reaction in a synchronous generator supplying leading power factor load is

Description : The armature reaction in a synchronous generator supplying leading power factor load is (A) magnetizing (B) demagnetizing (C) demagnetizing and cross-magnetizing (D) magnetizing and cross-magnetizing

Last Answer : The armature reaction in a synchronous generator supplying leading power factor load is magnetizing and cross-magnetizing

A 3-phase star-connected 75 MVA, 25 kV 3-phase synchronous generator has a synchronous reactance of...

Description : A 3-phase star-connected 75 MVA, 25 kV 3-phase synchronous generator has a synchronous reactance of 1.0 p.u. The per unit value to a 90 MVA base and 30 kV is (A) 2/15 p.u. (B) 5/6 p.u. (C) 1.0 p.u. (D) 1.2 p.u.

Last Answer : A 3-phase star-connected 75 MVA, 25 kV 3-phase synchronous generator has a synchronous reactance of 1.0 p.u. The per unit value to a 90 MVA base and 30 kV is 5/6 p.u.

A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now...

Description : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed (a) The same power but at a leading power factor (b) The same power ... a lagging power factor (c) More power at unity power factor (d) Less power at unity power factor

Last Answer : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed The same power but at a lagging power factor 

Consider the following statements regarding capability curves of a synchronous generator :

Description : Consider the following statements regarding capability curves of a synchronous generator :  1. The MVA loading should not exceed the generator rating.  2. The field current should not be allowed to exceed a ... 4. The load angle must be more than 90°.  Which of the above statements are correct ?

Last Answer : Consider the following statements regarding capability curves of a synchronous generator :  1. The MVA loading should not exceed the generator rating.  2. The field current should not be allowed to exceed a ... .  Which of the above statements are correct ? 1, 2 and 3 only