Electrical Engineering · Question Bank

DC Generators

196 questions · page 7 of 10. Answer in your head first, then check the solution.

📘 EE Mock Board Exam
TypeAll 196Problem solving 69Objective 127
DifficultyAll 196Easy 146Medium 41Hard 9
#121📘 EE Pocket Reviewer RojasEasy
In dc generators, the generated emf is directly proportional to which of the following?
ANumber of armature current paths
BField current
CPole flux
DNumber of dummy coils in the armature
#122📘 EE Pocket Reviewer RojasEasy
What is the purpose of placing the armature windings of the dc generator on the rotor?
ATo save the iron
BTo reduce the losses
CTo reduce the armature reaction
DTo facilitate commutation
#123📘 EE Pocket Reviewer RojasEasy
What is the classification of a dc generator that receives its field excitation from internal source?
ASelf-excited
BSeparately excited
CInternally excited
DUnder excited
#124📘 EE Pocket Reviewer RojasEasy
DC generators works on the principle of ____
AFleming's left hand rule
BFleming's right hand rule
CLenz’ law
DJoule’s law
#125📘 EE Pocket Reviewer RojasEasy
What is the major effect of the phenomenon called “armature reaction”?
AIt can cause the total flux to decrease
BIt can cause partial short circuit in the armature
CIt can cause the armature core to run wild
DIt can cause big power loss in the armature
#126📘 EE Pocket Reviewer RojasEasy
What is the main function of the interpoles in a dc generator?
ATo minimize friction between brushes and commutator
BTo minimize wear and tear between brushes and commutator
CTo minimize sparking between the brushes and the commutator
DNone of these
#127📘 EE Pocket Reviewer RojasEasy
Which of the following dc generators are suitable for running in parallel?
ASeries generators
BShunt generators
CCompound generators
DAny of these
#128📘 EE Pocket Reviewer RojasEasy
How does an interpole winding be connected in a dc generator?
AIn series with the armature windings
BIn parallel with the field winding
CIn series with the field windings
DIn parallel with the armature windings
#129📘 EE Pocket Reviewer RojasEasy
An “exciting current” is one that is required in which of the following?
ATo create a magnetic field
BTo charge a battery
CTo excite a synchronous motor
DTo build up a dead circuit
#130📘 EE Pocket Reviewer RojasEasy
When cleaning a commutator which of the following is never used?
ASandpaper
BClean cloth
CEmery
DBoth A and B
#131📘 EE Pocket Reviewer RojasEasy
In a dc machine, which one is a bigger loss in comparison to other losses?
AStray power loss
BCopper loss
CMechanical loss
DEddy current loss
#132📘 EE Pocket Reviewer RojasEasy
Which of the following will cause generator brushes to burn?
ABrushes not in neutral plane
BGenerator overloaded
CWeak brush springs
DAll of these
#133📘 EE Pocket Reviewer RojasEasy
Which generators would you prefer for feeding long dc transmission lines?
ASeries generator
BShunt generator
CFlat compounded generator
DOver-compounded generator
#134📘 EE Pocket Reviewer RojasEasy
Which of the following losses occurs in the yoke of a dc generator?
AIron loss
BCopper loss
CHeat loss
DNo losses
#135📘 EE Pocket Reviewer RojasEasy
In a dc generator, the generated emf is dependent on which of the following?
AFlux only
BSpeed only
CBoth flux and speed
DNeither flux nor speed
#136📘 EE Pocket Reviewer RojasEasy
What is the purpose of laminating the armature core in a dc generator?
AReduce the eddy current loss
BInsulate the core from overheating
CProvide passage for cooling air
DReduce the weight of the core
#137📘 EE Pocket Reviewer RojasEasy
How do you call a dc compound generator whose full-load terminal voltage is equal to the no-load terminal voltage?
AUnder-compounded
BFlat-compounded
CCumulative-compounded
DOver-compounded
#138📘 EE Pocket Reviewer RojasEasy
Grooves around the circumference of a commutator indicates which of the following?
AHigh mica
BImproper brushes
COpen armature circuit
DImproper brush staggering
#139📘 EE Pocket Reviewer RojasEasy
What is the purpose of staggering brushes?
ATo even out the load
BTo reduce chattering
CTo prevent the uneven wear on the commutator
DTo cover more area on the commutator segments
#140📘 EE Pocket Reviewer RojasEasy
Equalizer rings are necessary in dc machines if the armature is using what type of windings?
AWave wound
BLap wound
CDuplex wound
DSimplex wound

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