单项选择题
An alternator is being paralleled with one on the lineAt the INSTANT the circuit breaker is closed, the frequency of the incoming alternator will normally （）.
A.increase
B.not change
C.decrease
D.be exactly 60 hertz
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相关考题
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单项选择题
Current flowing in only one direction is called （）
A.alternating current
B.omnidirectional current
C.direct current
D.sinusoidal current -
单项选择题
Accidental grounds in a shipboard electrical system must be repaired as soon as possible as they will （）
A.result in immediate power outages
B.damage circuit breakers
C.appear on the ground detection system
D.damage insulation and may cause outages -
单项选择题
Prior to closing the breaker when paralleling two AC generators, the recommended practice is to have the frequency of the incoming machine （）
A.slightly less than the line frequency
B.the same as the line frequency
C.slightly greater than the line frequency
D.All of the above
