Electrical Engineering · Question Bank
DC Generators
146 of 196 questions match · page 8 of 8. Answer in your head first, then check the solution.
#141📘 EE Pocket Reviewer RojasEasy
Which one is true about the polarity of the interpoles in a dc generator?
AThe same as that of the main poles ahead
BOpposite to that of the main pole ahead
CIt has no polarity since it does not play an important role in generating an emf
DEither north or south depending on number of interpoles
#142📘 EE Pocket Reviewer RojasEasy
How can the residual magnetism of a dc shunt generator be restored assuming it is accidentally destroyed?
AGround the shunt field
BConnect the shunt field to an ac source
CConnect the shunt field to a dc source
DReverse the connection of the shunt field
#143📘 EE Pocket Reviewer RojasEasy
What is the purpose of having a dummy coil in a dc machine?
ATo eliminate armature reaction
BTo reduce the hysteresis loss
CTo eliminate harmonics developed in the armature
DTo mechanically balance the armature core
#144📘 EE Pocket Reviewer RojasEasy
What is the reason why poles of a dc machine are often laminated?
ATo reduce pulsation loss
BTo reduce the iron weight
CTo reduce armature reaction
DTo dissipate more heat
#145📘 EE Pocket Reviewer RojasEasy
Which one is a cause for excessive sparking at the brushes?
ALoose coupling
BWorn bearings
CShaft is not properly aligned
DDirt on the commutator segments
#146📘 EE Pocket Reviewer RojasEasy
What is the advantage of using carbon brushes than using copper brushes?
AIt can reduce sparking
BIt has a lower resistance
CIt has a longer life
DIt can reduce armature reaction
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