单项选择题

The unit "hertz" is equivalent to （）

A.coulombs per second
B.revolutions per second
C.revolutions per minute
D.cycles per second

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单项选择题

When paralleling two AC generators, the frequency of the machine coming on-line, immediately prior to closing its breaker, should be （）

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

单项选择题

When two AC generators are being paralleled, the breaker should be closed with the synchroscope pointer mating in the （）

A."slow" direction, just before the 12 o'clock position
B."fast" direction, just after the 12 o'clock position
C."fast" direction, just before the 12 o'clock position
D."slow" direction, just after the 12 o'clock position

单项选择题

AC voltmeters are generally calibrated to read the （）

A.instantaneous voltage
B.average voltage
C.RMS voltage
D.peak voltage