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英译汉：power factor
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考题
When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is _____.A.laggingB.leadingC.maximumD.minimum
考题
Which of the following statements represents an advantage of an electromagnetic clutch?A.Large misalignments can be tolerated between the shaft and engine couplingB.Slip is held to a minimum when reversing shaft rotationC.Engine torsional vibrations to the driven shaft are eliminatedD.It aids in maintaining power factor
考题
The power factor of an AC generator operating singularly is determined by the_______ .A.connected loadB.prime mover speedC.field excitationD.generator's rated voltage
考题
When you are making a high potential test on a piece of repaired electrical machinery, a rise in leakage current indicates _______.A.good insulationB.bad insulationC.high insulation power factorD.a high slot discharge factor
考题
For _______the power is supplied by main switchboard directly not through sub-boardA.saving network costB.improving the reliability of supplying power to important loadC.preventing sequence reversingD.increasing the power Factor of important load
考题
材料：The field current supply in older machines comes from a lower voltage direct current generator or exciter on the same shaft as the alternator. Modern machines however are either statically excited or of the high-speed brush-less type. The exciter is required to operate to counter the effects of power factor for a given load. The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle. With a purely resistance load the voltage and the current are in phase, giving a power factor of one. The power consumed is therefore the product of voltage and current. Inductive or capacitive loads, combined with resistance loads, produce lagging or leading power factors which have a value less than one.The power consumed is therefore the product of current, voltage and power factor. The alternating current generator supplying a load has a voltage drop resulting from the load. When the load has a lagging power factor this voltage drop is considerable. Therefore the exciter, in maintaining the alternator voltage, must vary with load current and also the power factor. The speed change of the prime mover must also be taken into account.问题： The word “machines” in the passage refers to _____.A.the direct current generatorB.the alternating current generatorC.the exciterD.the prime moverWhich of the following statements is true according to the passage ?A.With a purely resistance load, the power factor is zeroB.Inductive loads combined with resistance loads produces leading power factorsC.Capacitive loads combined with resistance loads produces lagging power factorsD.With a purely resistance load, the phase angle is zeroWhen the load has a lagging power factor this voltage drop is considerable. This sentence means that _____.A.with a purely resistance load, the voltage drops too muchB.there is a considerable voltage drop in the capacitive load combined with resistance loadC.when the load is the capacitive load combined with resistance load, the voltage drops to zeroD.when the load is the inductive load combined with resistance load, the voltage drop is fairly largeThe exciter must vary with: ① load current ② the power factor, ③ speed change of the prime mover.A.①B.②C.①②D.①②③请帮忙给出每个问题的正确答案和分析，谢谢！
考题
The customer intends to install a 7315-CR2 into a p690 frame. What should the pSeries technical specialist tell the customer？（）A、The HMC is a 19" form factor.B、The HMC is a 24" form factor.C、The HMC requires a 100-120 volt power connection.D、The HMC requires a 200-240 volt power connection.
考题
单选题A three-phase alternator operates at 450 volts with a power factor of 0~8.If the ammeter indicates 250 amperes, what should be the KW meter reading （）.A
90~0 kwB
127~27 kwC
155~70 kwD
194~85 kw
考题
单选题Which of the following statements represents an advantage of an electromagnetic clutch?（）A
Large misalignments can be tolerated between the shaft and engine couplingB
Slip is held to a minimum when reversing shaft rotationC
Engine torsion vibrations to the driven shaft are eliminatedD
It aids in maintaining power factor
考题
单选题The load between two steam-driven alternators operating in parallel may be adjusted by varying （）A
the speed of the alternatorsB
the field strength of the machinesC
the power factor of the alternatorsD
steam supply to the prime movers
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When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is （）A
laggingB
leadingC
maximumD
minimum
考题
单选题When current and voltage reach maximum values at the same time, the power factor is（）A
minimumB
maximumC
leadingD
lagging
考题
单选题To （） , the power is supplied by main switchboard directly not though sub-board.A
save network costB
improve the reliability of supplying power to important loadC
prevent sequence reverseD
increase the power factor of important load
考题
单选题Why is it desirable to operate paralleled AC generators at the same power factor?（）A
Circulating currents are kept to a minimumB
Field excitation losses are kept to a minimumC
Generator rotors will have a lesser tendency to huntD
Because a power factor increase will decrease kilowatt output
考题
单选题The power factor is a measure of the phase difference between voltage and current and is expressed as the（） of the phase angle.A
sineB
cosineC
tangentD
cotangent
考题
单选题In an alternating current electrical system, a low system power factor is a direct sign of （）A
wasted energyB
efficient operationC
a short in the exciter field windingsD
an excessive number of minor system grounds
考题
单选题The most important factor in engine performance is the actual power output at the end of the crankshaft available for doing workThis is known as （）.A
indicated horsepowerB
brake horsepowerC
net horsepowerD
friction horsepower
考题
单选题The customer intends to install a 7315-CR2 into a p690 frame. What should the pSeries technical specialist tell the customer？（）A
The HMC is a 19 form factor.B
The HMC is a 24 form factor.C
The HMC requires a 100-120 volt power connection.D
The HMC requires a 200-240 volt power connection.
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