What is the basic difference between the primaries of ac  and dc rate generators?

1 Answer

Answer :

The method of primary excitation (ac and permanent magnet).

Related questions

Description : What are the three classifications of dc generators?

Last Answer : Series-wound, shunt-wound, and compound-wound

Description : Why are drum-type armatures preferred over the Gramme ring armature in modern dc generators?

Last Answer : Drum-type armatures are more efficient, because flux lines are cut by both sides of each coil.

Description : Ships’ generators produce 450-volt, three-phase, ac power; however, most equipment uses 117-volt, single-phase power What transformers and connections are used to convert 450- volt, threephase power to 117-volt, single-phase power?

Last Answer : A method of generating oscillations, a method of turning the oscillations on and off (keying), and an antenna to radiate the energy.

Description : AC and DC generators are similar in that they _____________. A. both generate alternating voltages B. both rectify the voltage before delivery C. are constructed at the same physical size for the same kilowatt rating D. both supply three-phase power

Last Answer : Answer: A

Description : What Is Basic Principle Of Operation Of Alternators/dc Generators?

Last Answer : They are working on the fundamental principle based on Faraday’s Laws of Electromagnetic Induction. This law states that, When a current carrying conductor moves in magnetic field, it induces an EMF.

Description : What are your thoughts on closed primaries?

Last Answer : answer:I'm fine with it. I just think in states with closed primaries there should be a law that at the time of registration people are warned the state has closed primaries and what that means. I ... who want a say in the primaries register with a party, even when at heart they are independents.

Description : The decision in this 1945 federal case put an end to the discriminatory "white primaries" in Georgia.?

Last Answer : King vs Chapman

Description : Which of these people did not take part in the presidential primaries of 2008? (A) John McCain (B) Barack Obama (C) Hillary Clinton (D) George Bush 

Last Answer : (D) George Bush  

Description : Why does using ac vice dc bias voltage result in a stronger output signal?

Last Answer : Because an ac bias voltage of the proper frequency and level places the input signal away from both steps in the magnetism curve. The result is two undistorted output signals that are combined into one strong output.

Description : What are three advantages of adding an ac bias voltage to the input signal instead of adding a fixed dc bias voltage?

Last Answer : a. Reproduces a stronger output signal. b. Greatly improves the SNR. c. Greatly reduces the natural tape hiss.

Description : Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio (SNR)?

Last Answer : With dc bias, the SNR is poor because only a small portion of the magnetism curve is straight enough to use, thus the output signal is weak compared with the natural tape hiss.

Description : What component causes a generator to produce dc voltage rather than ac voltage at its output terminals?

Last Answer : A commutator

Description : Why is the dc scale on a multimeter different than the ac scale?

Last Answer : The meter movement reacts to average ac voltage and current and the effective value is desired.

Description : List three meter movements that can measure either ac or dc without the use of a rectifier.

Last Answer : Electrodynamic, moving vane, and hot-wire or thermocouple.

Description : What are the three basic types of ac motors?

Last Answer : Series, synchronous, induction.

Description : What are report program generators used for?

Last Answer : To generate programs to print detail and summary reports of data files.

Description : Motors, switches, voltage regulators, generators, etc., are a few examples of emi sources. What type of emi comes from these sources?

Last Answer : Man-made.

Description : Range-marker generators produce pulses based on what radar constant?

Last Answer : The radar mile (12.36 microseconds).

Description : What are the two classifications of wave generators according to their output waveshapes?

Last Answer : Sinusoidal and nonsinusoidal.

Description : What term applies to the use of two or more generators to supply a common load?

Last Answer : Parallel operation.

Description : What is the main disadvantage of series generators?

Last Answer : Output voltage varies as the load varies

Description : Lap windings are used in generators designed for what type of application?

Last Answer : Higher load currents are possible

Description : Generators convert mechanical motion to electrical energy using what principle?

Last Answer : Magnetic induction

Description : In signal generators, what device is used to regulate the voltage of the output signal?

Last Answer : Attenuator.

Description : Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt ... generators are connected in series. D. The equalizer connection parallels the series fields of all machines.

Last Answer : Answer: D

Description : An equalizing connection between two compound-wound DC generators when paralleled, serves to _____________. A. reverse the polarity of the incoming generator as the series field weakens B. automatically ... the series field of the incoming generator D. parallel the series fields of the generators

Last Answer : Answer: D

Description : Modern DC generators are fitted with commutating poles to _____________. A. prevent motorizing B. reduce sparking C. reduce the load on the main poles D. reduce spring pressure on the brushes

Last Answer : Answer: B

Description : Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt field rheostats ... are connected in series. D. The series fields of both generators are connected in parallel.

Last Answer : Answer: D

Description : In a diesel electric plant, raising the generator's field excitation will cause the DC propulsion motor to ________. A. increase in speed B. decrease in speed C. affect generator speed only D. affect main motor speed if done in conjunction with higher generator engine speeds

Last Answer : Answer: A

Description : What Are The Major Parts Of The Dc Generators?

Last Answer : Yoke Poles Field winding Armature Armature winding Commutator brushes

Description : What Are The Conditions To Be Satisfied For Parallel Operation Of Dc Generators?

Last Answer : The polarities of the generators must be same or the connections must be interchanged till they become same. The voltages of both the generators must be equal. The change of voltage with ... and negative terminals of generators must be connected properly to the positive and negative of busbar.

Description : In DC generators, armature reaction is produced actually by (A) Its field current. (B) Armature conductors. (C) Field pole winding. (D) Load current in armature.

Last Answer : Ans: D Because load current in armature gives rise to armature mmf which react with main field mmf.

Description : DC GENERATORS MCQ

Last Answer : 101. Wave winding is composed of (a) any even number of conductors (b) any odd number of conductors (c) that even number which is exact multiple of poles + 2 (d) that even number ... increase the field resistance (c) increase the speed of primemover (d) check armature insulation resis¬tance Ans: a

Description : Identify the increasing order of voltage regulation of the following dc generators a same load :  (A) differential compound, shunt and under compound  (B) shunt, differential compound and ... C) under compound, shunt and differential compound  (D) shunt, under compound and differential compound

Last Answer : Identify the increasing order of voltage regulation of the following dc generators a same load : under compound, shunt and differential compound 

Description :  Which of the following generators is used for DC arc welding application ? (A) Series generator (B) Shunt generator (C) Differential compound generator (D) Over -compound generator

Last Answer : A

Description : What is the other name used for DC generators? A. Dynamos B. Alternator C. Capacitor D. Dynamotor 

Last Answer : Dynamos is the other name used for DC generators.

Description : In DC generators, armature reaction is produced by the: (A) field current (B) armature conductors (C) field pole winding (D) load current in armature

Last Answer : In DC generators, armature reaction is produced by the: load current in armature

Description : In DC generators lamination core are generally made of?

Last Answer : In DC generators lamination core are generally made of silicon steel.

Description : Which of the synchroscope illustrations depicts the appropriate direction of rotation and position for closing the circuit breaker when paralleling AC generators? EL-0053 A. A B. B C. C D. D

Last Answer : Answer: D

Description : The division of the reactive KVA load between paralleled AC generators is initiated by the ______________. A. prime mover governors B. voltage regulators C. phase balance relay D. proportioner

Last Answer : Answer: B

Description : An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. ... between the armature and the bus D. cause high currents to be induced in the field windings

Last Answer : Answer: D

Description : If three AC generators are operating in parallel, and one of them were to 'pull out' of synchronism with the other two generators, the ____________. A. normally operating AC generators will ... AC generators will overspeed and unload D. AC generator pulling out of synchronism will become motorized

Last Answer : Answer: B

Description : Two AC generators of the same capacity are operating in parallel. One with a zero speed droop setting and the other with a 5% speed droop. If its capacity is not exceeded, the unit whose ... B. maintain the frequency of the system C. have poor sensitivity characteristics D. have poor power response

Last Answer : Answer: B

Description : Prior to closing the breaker when paralleling two AC generators, the recommended practice is to have the frequency of the incoming machine _____________. A. slightly less than the line frequency B. the same as the line frequency C. slightly greater than the line frequency D. all of the above

Last Answer : Answer: C

Description : When paralleled, AC generators must have the same _________. A. frequency B. number of phases C. phase rotation D. all of the above

Last Answer : Answer: D

Description : When paralleling two AC generators, the frequency (cycles) of the incoming generator, just prior to closing the circuit breaker, should be _____________. A. slightly less than the frequency of the generator on ... C. slightly more than the frequency of the generator on the line D. all of the above

Last Answer : Answer: C

Description : When paralleling two AC generators, the frequency of the machine coming online, immediately prior to closing its breaker, should be ____________. A. slightly less than the oncoming generator frequency B. the ... bus frequency C. slightly greater than the bus frequency D. the same as the bus voltage

Last Answer : Answer: C

Description : When paralleling two AC generators, the frequency of the incoming machine immediately prior to closing its breaker should be ____________. A. controlled by placing the governor switch in the automatic ... regulator C. slightly greater than the bus frequency D. slightly less than the bus frequency

Last Answer : Answer: C

Description : If two AC generators have just been placed in parallel, the true power load is initially distributed evenly by _____________. A. a balance coil B. changing field excitation C. adjusting the governor control settings D. a rheostat

Last Answer : Answer: C

Description : When two AC generators are being paralleled, the breaker should be closed with the synchroscope pointer rotating in the ____________. A. 'slow' direction, just before the 12 o'clock position B. 'fast' ... just before the 12 o'clock position D. 'slow' direction, just after the 12 o'clock position

Last Answer : Answer: C