单项选择题
A.ampere B.kilovolt C.watt D.farad
In an alternating current electrical system, a low syst...
单项选择题In an alternating current electrical system, a low system power factor is a direct sign of （）
A.wasted energy B.efficient operation C.a short in the exciter field windings D.an excessive number of minor system grounds
An alternator is being paralleled with one on the lineA...
单项选择题An alternator is being paralleled with one on the lineAt the INSTANT the circuit breaker is closed, the frequency of the incoming alternator will normally （）.
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
