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 （）
单项选择题 Which of the following should be the FIRST step in removing a generator from parallel operation?（）
单项选择题 Electrical power is expressed in （）
