Two alternators A and B are operating in parallel and sharing equally a unity pf load. If the excitation of A is increased, which of the following will happen?
AA will become lagging while B will become leading
BA will become leading while B will become lagging
CBoth A and B will operate on leading pf
DBoth A and B will operate on lagging pf
#42📘 EE Pocket Reviewer RojasEasy
In a big alternator, which one is the moving part?
AYoke
BPoles
CArmature
DCommutator
#43📘 EE Pocket Reviewer RojasEasy
At leading power factor, what is the effect of the armature flux of the alternator to its rotor flux?
AIt will aid
BIt will distort
CIt will oppose
DIt does not have any effect
#44📘 EE Pocket Reviewer RojasEasy
What type of voltage is being:applied to the field windings of an alternator?
AHigh dc voltage
BLow dc voltage
CHigh ac voltage
DLow ac voltage
#45📘 EE Pocket Reviewer RojasEasy
In an alternator, what relationship is being shown in a magnetization curve?
AMagnetic flux vs excitation current
BReactive power vs real power
CExcitation current vs terminal voltage
DLoad current vs excitation current
#46📘 EE Pocket Reviewer RojasEasy
Which of the following methods are commonly used in synchronizing alternators?
ADark lamp method only
BBright lamp method only
CDark lamp method and a synchroscope
DBright lamp method and a synchroscope
#47📘 EE Pocket Reviewer RojasEasy
Pitch factor is defined as the ratio of the voltage induced in a
AFull pitch coil to a short pitch coil
BShort pitch coil to a full pitch coil
CShort pitch coil to a long pitch coil
DLong pitch coil to a short pitch coil
#48📘 EE Pocket Reviewer RojasEasy
What will happen if a high speed alternator uses salient poles?
AReduced windage loss but excessive noise
BReduced windage loss and lesser noise
CExcessive windage loss and excessive noise
DExcessive windage loss but reduced noise
#49📘 EE Pocket Reviewer RojasEasy
When two or more alternators are in parallel operation, their kW load share is changed by changing which of the following?
ADriving torque
BExcitation
CEither A or
DBoth A and B simultaneously
#50📘 EE Pocket Reviewer RojasEasy
Low speed alternators are driven by which of the following prime movers?
ASteam turbines
BHydraulic turbines
CSteam engines
DAny of these
#51📘 EE Pocket Reviewer RojasEasy
What is the reason why it is not advisable to connect a stationary alternator to a live bus bars?
AIt will get short circuited
BIt will likely to run as a synchronous motor
CIt will cause the bus bar voltage to increase
DIt will disturb the generated emf of the other alternators connected in the bus
#52📘 EE Pocket Reviewer RojasEasy
If the prime mover of an alternator supplying a load to an infinite bus is suddenly shut down what will happen to the alternator?
AIt will stop running
BIt will continue to run as an alternator
CIt will continue to run as a synchronous motor in the reverse direction
DIt will continue to run as a synchronous motor in the same direction
#53📘 EE Pocket Reviewer RojasEasy
Alternators uses normally what type of field?
ARotating field type
BStationary field type
CEither
DNone of these
#54📘 EE Pocket Reviewer RojasEasy
When an alternator is supplying a zero lagging pf load, the armature reaction will produce which of the following conditions?
ADemagnetization of the main field flux
BMagnetization of the main field flux
CCross magnetization of the main field flux
DAll of these
#55📘 EE Pocket Reviewer RojasEasy
Which of the following alternator parts plays an important role in over speed protection?
ACircuit breaker
BOverload relay
CGovernor
DDifferential protection
#56📘 EE Pocket Reviewer RojasEasy
Which of the following types of rotors is best suitable for turbo alternators?
ASalient pole type
BNon-salient pole type or cylindrical rotor
CEither A or
DNone of these
#57📘 EE Pocket Reviewer RojasEasy
In an alternator, which of the following is affected by armature reaction?
ADriving speed of armature
BGenerated voltage per phase
CArmature copper loss
DOperating power factor
#58📘 EE Pocket Reviewer RojasEasy
What is the usual connection of the armature windings of a three-phase alternator?
ADelta
BWye
CWye-delta
DDelta-wye
#59📘 EE Pocket Reviewer RojasEasy
Which statement is true about an alternator operating at unity pf?
AGenerated emf is equal to the terminal emf
BGenerated emf is less than the terminal emf
CGenerated emf is more than the terminal emf
DEither B or C, depending on how big is the load
#60📘 EE Pocket Reviewer RojasEasy
A 3-phase alternator is running with a phase sequence of ABC for its three output voltages. If the direction of rotation is reversed, the phase sequence will become which of the following?
