單項(xiàng)選擇題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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1.單項(xiàng)選擇題The frequency of an AC generator is controlled by the ()

A.rheostat
B.governor
C.exciter
D.capacitor

2.單項(xiàng)選擇題Capacitance is the property of an electric circuit opposing a change in the ()

A.current in the circuit
B.voltage in the circuit
C.inductance in the circuit
D.resistance in the circuit

3.單項(xiàng)選擇題Inductance is the property of an electric circuit that ()

A.opposes any change in the applied voltage
B.opposes any change in the current flow through the circuit
C.aids any changes in the applied voltage
D.aids any changes in the current through the circuit

4.單項(xiàng)選擇題The operator of electrical motors should keep a constant check on the loads they carry because ()

A.low loads necessitate frequent insulation cleaning
B.exceeding nameplate values shortens useful life
C.energy is wasted if full loading is not utilized
D.power factor correction methods are load dependent

5.單項(xiàng)選擇題Which of the listed sections of an emergency switchboard is used to supply power for alarm signals under emergency conditions?()

A.The generator and bus transfer section
B.The 450 volt, 60 cycle, 3 phase bus
C.The 120 volt, 3 phase, 60 cycle bus
D.The 24 volt DC bus