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

试卷相关题目

• 1The main generators are connected to ______.

  A.distribution boards

  B.section boards

  C.emergency switch boards

  D.main switch boards

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• 2Electric insulation is made of organic substances and so gradually ______with age.

  A.deteriorates

  B.increases

  C.are fouled

  D.becomes better

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• 3The load sharing characteristics of two diesel generators operating in parallel are mostly dependent on their governor ______.

  A.load limit settings

  B.idle speed settings

  C.speed limit settings

  D.speed droop settings

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• 4While paralleling two AC generators using synchronizing(同步的) lamps only, both lamps will go dark when the generators are ______.

  A.running at the same speed

  B.grounded

  C.of the same polarity(极性)

  D.in phase

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• 5The frequency of an alternator at a given RPM is determined by the ______.

  A.number of turns of wire in the armature coil

  B.number of magnetic poles

  C.strength of the magnets used

  D.output voltage

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• 6______is a machine by which electrical energy is transformed into mechanical energy.

  A.An alternator

  B.An electric motor

  C.A diesel engine

  D.A main switchboard

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• 7A ground in an electrical circuit outside the engine room ______.

  A.cannot be detected under normal conditions

  B.is of no consequence to engineering personnel

  C.is indicated at the branch circuit breaker panel

  D.is indicated by the ground detecting lamps on the main switchboard

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• 8Time delayed or delayed action-type fuses are designed to ______.

  A.prevent grounds in branch circuits

  B.prevent opens in motor circuits

  C.permit momentary overloads without melting

  D.guard lighting and electronic circuits

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• 9When voltage and current developed in an AC circuit reach their peak values at the same time, the power factor is ______.

  A.lagging

  B.leading

  C.maximum

  D.minimum

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• 10When there is a fire in a large electric motor, normally the very FIRST step is to ______.

  A.secure the electric supply

  B.ventilate area to remove smoke

  C.start the fire pump and lead out hose

  D.apply foam

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