网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
The voltage output of an AC generator is controlled by（）
A
varying the DC exciter voltage
B
varying the reluctance of the air gap
C
regulating the speed of the prime mover
D
shorting out part of the armature windings
参考答案
参考解析
解析：
暂无解析
更多 “单选题The voltage output of an AC generator is controlled by（）A varying the DC exciter voltageB varying the reluctance of the air gapC regulating the speed of the prime moverD shorting out part of the armature windings” 相关考题
考题
( ) can provide an asynchronous link between two ac electric power system with different nominal frequencies.
A.The HVDC (high voltage DC) transmissionB.The EHV (extra-high voltage) AC transmissionC.The AC distributionD.Generators
考题
The generator voltages are usually stepped up to the transmission voltage level by ( ).
A.series capacitorB.parallel reactorsC.step-up transformersD.step-down transformers
考题
The overall transfer function is the ratio of the transform. of the controlled variable to the transform. of ( ).
A.the controlled variableB.the reference inputC.the feedbackD.the output variable
考题
Overspeed of the diesel engine driving an electric generator could cause ______.A.low voltage tripB.reverse power tripC.damage to windingsD.excessive exhaust temperatures
考题
In an AC.synchronous motor electric propulsion plant,propeller speed is controlled by()
A.prime mover speedB.number of energized main motor polesC.propulsion generator field strengthD.electric coupling field strength
考题
The output voltage of a 440 volt, 60 hertz, AC generator is controlled by theA.prime mover speedB.exciter output voltageC.load on the alternatorD.number of poles
考题
The frequency of an AC generator is controlled by theA.rheostatB.governorC.exciterD.capacitor
考题
The frequency of an AC generator is controlled by the ___.A.rheostatB.governorC.exciterD.capacitor
考题
单选题The output voltage of a three-phase alternator is regulated by the （）.A
AC voltage to the armatureB
AC voltage to the fieldC
DC voltage to the armatureD
DC voltage to the field
考题
单选题The purpose of DC generator brushes is to （）.A
neutralize armature reactionB
conduct electric current to an outside circuitC
convert DC current to AC currentD
provide excitation to a DC generator
考题
单选题A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an （）A
rotorB
statorC
exciterD
armature
考题
单选题The instantaneous reduction in voltage of an AC generator, resulting from an increase in load, and prior to the automatic voltage regulator correcting the situation, is called voltage （）.A
droopB
dropC
dipD
regulation
考题
单选题The power factor of an AC generator operating singularly is determined by the （）A
connected loadB
prime mover speedC
field excitationD
generators rated voltage
考题
单选题The power factor at which a paralleled AC generator operates is usually adjusted by the （）.A
connected loadB
prime mover speedC
field excitationD
generators rated voltage
考题
单选题When securing an AC generator, you should FIRST （）.A
open the generator circuit breakerB
switch the voltage regulator to “manual”C
decrease the field excitation to minimumD
reduce the load on the unit
考题
单选题The frequency of an AC generator is controlled by the （）A
rheostatB
governorC
exciterD
capacitor
考题
单选题The frequency output of an operating alternator is controlled by the （）.A
relative speed of the rotor polesB
number of turns of wire in the armature coilC
strength of the magnets usedD
output voltage
考题
单选题Self-excited a-cgenerator with "error operated" voltage control systems draw the full excitation power for the machine terminalsThis dispenses with the current transformers, reactors and capacitors necessary for accurate compounding, but renders the excitation system vulnerable to variations in its output voltageWhich of the following is correct about the generator mentioned according to the sentences above （）.A
It consumes no excitation powerB
It has current transformersC
Components are needed for accurate compoundingD
Its excitation system is vulnerable to voltage variations
考题
单选题Prior to starting an AC generator prime mover, the voltage regulator cutout switch should be placed in the （）A
manual positionB
bus neutral positionC
raise voltage positionD
transfer position
考题
单选题The alternating current generator supplying a load has a voltage drop resulted from the loadWhen the load has a lagging power factor this voltage drop （）.A
is smallB
may be neglectedC
is usefulD
is considerable
考题
单选题The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the （）.A
prime mover speedB
exciter output voltageC
load on the alternatorD
number of poles
考题
单选题The initial voltage of self-excitation generator set up by（）A
residual magnetismB
voltage regulatorC
electrical current for excitationD
the other running generator
考题
单选题The overspeeding of the diesel engine driving an electric generator could cause （）.A
low voltage trip to tripB
reverse power trip to tripC
damage to windingsD
excessive exhaust temperatures
考题
单选题Overspeed of the diesel engine driving an electric generator could cause（）.A
low voltage tripB
reverse power tripC
damage to windingsD
excessive exhaust temperatures
考题
单选题When paralleling two AC generators, the frequency of the machine coming on-line, immediately prior to closing its breaker, should be （）A
slightly less than the oncoming generator frequencyB
the same as the bus frequencyC
slightly greater than the bus frequencyD
the same as the bus voltage
考题
单选题The voltage developed by an AC generator is controlled by varying the （）A
speed of the prime moverB
AC excitation to the fieldC
DC excitation to the fieldD
DC excitation of the voltage regulator
考题
单选题A constant output voltage from an AC generator is maintained by the （）.A
prime mover governorB
exciter generatorC
voltage regulatorD
reverse power relay
热门标签
最新试卷
