The power factor is a measure of the phase difference between voltage and current and is expressed as the（） of the phase angle...

第1题

[单选题] The （） is a measure of the phase difference between voltage and current and is expected as the cosine of phase angle.

A、power B、efficiency C、effective power D、power factor

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第2题

[] （）is a function of the reactive / resistive characteristics of the load items and cannot be adjusted by manipulating the alternator control devices.

A、A.Power factor B、B.Power ratio C、C.compression ratio D、D.Compression factor

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第3题

[单选题] To （） , the power is supplied by main switchboard directly not though sub-board.

A、save network cost B、improve the reliability of supplying power to important load C、prevent sequence reverse D、increase the power factor of important load

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第4题

[单选题] Which of the following factors is the MOST important to consider when choosing an uninterruptible power supply （UPS） for a single server？（）

A、 UPS form factor B、 Server form factor C、 Server power supplys wattage rating D、 Desired runtime

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第5题

[单选题] Which of the following factors is the MOST likely cause of a power supply fan failure?（）

A、Extreme temperature variances B、Extreme humidity variances C、Power stability fluctuations D、Excessive dust accumulation

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第6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 small B、may be neglected C、is useful D、is considerable

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第7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 horsepower B、brake horsepower C、net horsepower D、friction horsepower

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第8题

[单选题] When current and voltage reach maximum values at the same time, the power factor is（）

A、minimum B、maximum C、leading D、lagging

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第9题

[单选题] The frequency of the alternating current generated by a synchronous generator is governed by the speed and the（）

A、full excitation B、load C、power factor D、number of poles

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The power factor is a measure of the phase difference between voltage and current and is expressed as the（） of the phase angle.

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