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单选题
An alternator switchboard has a synchroscope and synchronizing lamps, if the synchroscope is broken, which of the steps listed is the most essential before an alternator can be paralleled with the bus （）
A
The breaker should be closed when one synchronizing lamp is dark and the other is bright
B
The breaker should be closed when both synchronizing lamps are bright
C
The frequency meter should be used to determine that the incoming alternator frequency is slightly higher than the bus
D
A portable phase sequence indicator must be used to verify the information from the lamps
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更多 “单选题An alternator switchboard has a synchroscope and synchronizing lamps, if the synchroscope is broken, which of the steps listed is the most essential before an alternator can be paralleled with the bus （）A The breaker should be closed when one synchronizing lamp is dark and the other is brightB The breaker should be closed when both synchronizing lamps are brightC The frequency meter should be used to determine that the incoming alternator frequency is slightly higher than the busD A portable phase sequence indicator must be used to verify the information from the lamps” 相关考题
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any pointer positionDue to failure of one of the carbon brushes the excitation voltage is lost on one alternator that operating in parallel.Then that alternator will()
A.completely loose its share of the load causing the auxiliary engine to speed up.B.overload due to reduced voltage output and increased currentC.continue to share the active load(kw)but have high very reactive loadD.try to take all the load and so trip the main circuit breaker
考题
Where could you monitor the correct instant for synchronizing without aid of synchroscope or synchronizing lamp?
A.Distribution boardB.Section boardC.Emergency switchboardD.Main switchboard
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An alternator is being paralleled with one on the line At the instant the circuit breaker is close, the frequency of the incoming alternator will normallyA.increaseB.not changeC.decreaseD.be exactly 60 hertz
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单选题（）is not installed on the emergency switchboard.A
Ammeter and changeover switchB
Speed governor deviceC
SynchroscopeD
Wattmeter
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单选题（）is not installed on the emergency switchboard.A
AmmeterB
VoltmeterC
WattmeterD
Synchroscope
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单选题With No~1 and No~2 alternators running in parallel and the KW loads equally shared, one alternator is drawing much higher current than the other.What does this indicate?（）A
The alternators are not generating the same voltages and should be adjusted on automatic voltage regulator rheostatsB
Alternator frequencies are different and should be adjusted on the governor speed controllersC
Alternators are out of phase and should be tripped and paralleled againD
One alternator has lost one of its phases
考题
单选题The frequency of an alternator is controlled from the main switchboard by adjusting the（）A
frequency meterB
voltage regulatorC
governor controlD
sychroscope switch
考题
单选题An indicator on the main switchboard should show （） the emergency battery is in service or not.A
thatB
whenC
ifD
whether
考题
单选题A switchboard, for a AC electrical distribution system, will be provided with which of the following components （）.A
Frequency meterB
AmmeterC
VoltmeterD
All of the above
考题
单选题（） is a machine by which electrical energy is transformed into mechanical energy.A
An alternatorB
An electric motorC
A diesel engineD
A main switchboard
考题
单选题（）is not a part of the main switchboard.A
BusbarB
Load panel of main generatorC
Paralleling panelD
Shore connection box
考题
单选题（）is power supplied by main switchboard directly not through sub-board.A
Deck machineryB
Little power loadC
Some important loadD
stationary submersible pump
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单选题The purpose of a main switchboard circuit breakers reverse-power trip is to （）.A
prevent main circuit overloadB
protect the circuit breaker blowout coilC
prevent alternator motorizationD
prevent low voltage tripout
考题
单选题（）is not installed on the emergency switchboard.A
Control panelB
Paralleling panelC
Load panelD
Busbar
考题
单选题（）is a function of the reactive / resistive characteristics of the load items and cannot be adjusted by manipulating the alternator control devices.A
Power factorB
Power ratioC
compression ratioD
Compression factor
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单选题The frequency of an alternator at a given RPM is determined by the （）.A
number of turns of wire in the armature coilB
number of magnetic polesC
strength of the magnets usedD
output voltage
考题
单选题The correct phase rotation of a three-phase alternator can be checked with a（）A
dynamometerB
power factor meterC
three-phase motorD
polyphase voltmeter
考题
单选题A switchboard for an AC electrical system requires the use of which of the following devices（）.A
Frequency meterB
OhmmeterC
Induction voltage regulatorD
Current transformer governor
考题
单选题The separate supplies are connected in either star or delta formationThe star formation is most commonly used and requires（） slip-rings on the alternator.A
twoB
threeC
fourD
five
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