COBIT（Control Objectives for Information and related technology)是一套企业级的关注业务需要

The frequency of an AC generator is controlled by the

A.rheostat

B.governor

C.exciter

D.capacitor

The frequency of an AC generator is adjusted by means of the _____.

A.main alternator field rheostat

B.exciter field rheostat

C.prime mover governor control

D.equalizing reactor

The voltage developed by an AC generator is controlled by varying the _____.

A.speed of the prime mover

B.AC excitation to the field

C.DC excitation to the field

D.DC excitation of the voltage regulator

To increase the frequency of an operating AC generator, you should _____.

A.increase the field excitation

B.decrease the field excitation

C.increase the number of magnetic poles

D.increase the speed of the prime mover

The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the

A.prime mover speed

B.exciter output voltage

C.load on the alternator

D.number of poles

A.slightly less than the oncoming generator frequency

B.the same as the bus frequency

C.slightly greater than the bus frequency

D.the same as the bus voltage

A．GENERATOR

B． MOTOR

C． CATHODE

D． FREQUENCY

A.a variable-speed AC generator

B.a fixed-speed AC generator

C.an air blower

D.a DC generator

When securing an AC generator, you should FIRST _____.

A.open the generator circuit breaker

B.switch the voltage regulator to "manual"

C.decrease the field excitation to minimum

D.reduce the load on the unit