单项选择题
To equalize the power factor of two alternators operating in parallel, the （）
A.field excitation of both units is adjusted B.governors of both units are adjusted C.phase sequence is altered D.kilowatt load is evenly divided
单项选择题 An advantage of DC motors over AC motors is that they （）
单项选择题 Which of the following devices are protected from being motorized by a reverse-power relay?（）
单项选择题 If the length of a wire is halved and the cross-sectional area is doubled, the resistance will be （）
