单项选择题
A.increase B.not change C.decrease D.be exactly 60 hertz
Current flowing in only one direction is called （）A.alt...
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
Accidental grounds in a shipboard electrical system mus...
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
Prior to closing the breaker when paralleling two AC ge...
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
