單項(xiàng)選擇題

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

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單項(xiàng)選擇題

AC voltmeters are generally calibrated to read the （）

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

單項(xiàng)選擇題

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 （）.

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