世代交替(alternation of generation)

相似题目

• The output voltage of a three-phase alternator is regulated by the （）.

  A . AC voltage to the armature B . AC voltage to the field C . DC voltage to the armature D . DC voltage to the field

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

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

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• Patients" bills of rights require that they （） informed about their condition and about alternatives for treatment.

  A . are B . might be C . should be D . were

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• The frequency of an alternator is controlled from the main switchboard by adjusting the（）

  A . frequency meter B . voltage regulator C . governor control D . sychroscope switch

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• All of these alternatives are carbon-based fuels（）molecules are smaller and simpler than those of gasoline.

  A . which B . who C . what D . whose

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• The operation of （） two alternators requires the voltages to be equal and also in phase.

  A . paralleling B . series-mounting C . running D . control

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• 世代交替（alternation of generations）

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• （） is provided to alternators, in the event of prime mover failure to ensure that the alternator does not act as a motor.

  A . Reverse current protection B . Reverse power protection C . Synchronising device D . Frequency meter

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• Possible phase relationships between voltage and current in an alternating current circuit include which of the following conditions?（）

  A . Current and voltage may be in phase B . Current may lead the voltage C . Current may lag the voltage D . All of the above

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• 交替生长（Alternative growth）

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• 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 lam

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• In an alternating current electrical system, a low system power factor is a direct sign of （）

  A . wasted energy B . efficient operation C . a short in the exciter field windings D . an excessive number of minor system ground

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• The division of kilowatt load between two paralleled alternators is determined by the （）

  A . amount of field excitation of the leading machine B . load-speed characteristics of the governors C . amount of field excitation to the lagging machine D . type of alternator

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• The operation of paralleling two alternators requires the voltages to be （）and also in phase.

  A . zero B . eliminated C . different D . equal

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• 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 pole

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• Which of the following components are used to convert alternating current produced in the generator windings to direct current?（）

  A . Armature and equalizer B . Commutator and brushes C . Rotor and interpoles D . Field and exciter

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• The frequency output of an operating alternator is controlled by the （）.

  A . relative speed of the rotor poles B . number of turns of wire in the armature coil C . strength of the magnets used D . output voltage

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• The order of Heavenly Horse and that of Sea Horse can be changed alternatively.

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• What is the implying meaning of “Alternative Rock”?

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• There can be a formal assessment of purchase alternatives in business-to-business transactions.

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• One assumption of rationality is that we cannot know all of the alternatives.（)

  是 否

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• What is the alternative name of the World Bank？

  A．International Bank for Reconstruction and Development. B．International Financial Corporation. C．International Development Association. D．International Settlement Bank.

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• Genera Technologles 0rders 25 Inore tests before the elld of the year．

  A．Right B．Wrong C．Not mentioded

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• Two parties of the US alternate in governing. The two main parties are___（）

  A．the Republican Party and the Liberal Party B．The Democratic Party and the Liberal Party C．The Liberal Party and the Labour Party D．The Democratic Party and the Republican Party

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