单项选择题
Which of the following should be the FIRST step in removing a generator from parallel operation?（）
A.Trip the generator off the switchboard B.Turn off all electrical equipment C.Remove the load from the "off going" generator D.Increase the cycles of the generator staying on the line
单项选择题 Electrical power is expressed in （）
单项选择题 Which of the following materials is a good insulator?（）
单项选择题 To protect the rotor of a motor disassembled for maintenance or overhaul, it should be（）
