单项选择题
If two AC generators are to be operated in parallel, the load is distributed evenly by（）
A.means of rheostat the governor settings B.a balance coil excitation C.adjusting the governor settings D.changing excitation
单项选择题 If a voltmeter is connected across a line, it must be protected with a（）
单项选择题 When current and voltage reach maximum values at the same time, the power factor is（）
单项选择题 Which is an acceptable means of correcting high mica between commutator bars?（）
