You are attempting to parallel two AC generators, and the synchroscope(同步器) pointer is revolving in the fast direction. This indicates that the frequency of the incoming machine is ______.A.higher than the bus frequencyB.lower than the bus frequencyC.the same as the bus frequency but out of phase with itD.the same as the bus frequency and the circuit breaker may be closed at any pointer position
You are attempting to parallel two AC generators, and the synchroscope(同步器) pointer is revolving in the fast direction. This indicates that the frequency of the incoming machine is ______.
A.higher than the bus frequency
B.lower than the bus frequency
C.the same as the bus frequency but out of phase with it
D.the same as the bus frequency and the circuit breaker may be closed at any pointer position
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单选题While paralleling two AC generators using synchronizing lamps only, both lamps will go dark when the generators are （）.Arunning at the same speedBgroundedCof the same polarityDin phase
单选题When measuring AC current flow, you must always connect the meter （）Ain series with the power source and loadBin parallel with the power source and loadCinsuring correct polarityDusing the lowest range possible to prevent instrument damage
单选题You are docking a vessel starboard side to with the assistance of two tugs.You are attempting to hold the vessel off by operating both tugs at right angles to the vessel and at full power.You must ensure that（）.Asteerageway is not taken offBthe bow doesn't close the dock firstCthe bow closes the dock firstDthe ship has no headway at the time
单选题When two AC generators are being paralleled, the breaker should be closed with the synchroscope pointer mating in the （）Aslow direction, just before the 12 o'clock positionBfast direction, just after the 12 o'clock positionCfast direction, just before the 12 o'clock positionDslow direction, just after the 12 o'clock position
单选题When two DC generators operate in parallel, they are protected against motorizing by（）Ablow out coilsBgovernor relayCunder voltage tripsDreverse current trips
单选题If two AC generators are to be operated in parallel, the load is distributed evenly by（）Ameans of rheostat the governor settingsBa balance coil excitationCadjusting the governor settingsDchanging excitation
单选题You are attempting to parallel two AC generators, and the syncope pointer is revolving in the fast directionThis indicates that the frequency of the incoming machine is （）.Ahigher than the bus frequencyBlower than the bus frequencyCthe same as the bus frequency but out of phase with itDthe same as the bus frequency and the circuit breaker may be closed at any pointer position
单选题You are attempting to parallel two AC generators and the synchroscope pointer is revolving in the slow directionThis indicates that the frequency of the incoming machine is （）.Ahigher than the bus frequencyBlower than the bus freouencvCthe same as the bus frequency but out of phase with itDthe same as the bus frequency, and the circuit breaker may be closed at any pointer position
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