reduce current pulsations
reduce brush chatter
prevent uneven commutator wear
allow greater power generation
第1题：
In a modern three-phase A.C. synchronous brushes generator, the excitation winding is on the rotor. That means .
A.The generator need not excitation.
B.The winding on the rotor is for inputting excitation current.
C.There are three phase windings on the rotor.
D.The generator has no brushes.
第2题：
describe the procedure to start an emergency generator ?
第3题：
The child brushes her ______ every day.
A、tooths
B、teeth
C、teeths
D、tooth
第4题：
画笔（Brushes）调板中包含边线画笔（Stroke Brushes）（）
第5题：
The boy brushes his ________（牙齿） every day．
第6题：
The frequency of an AC generator is controlled by the ___.
A.rheostat
B.governor
C.exciter
D.capacitor
第7题：
A. Faulty driver; reinstall or update driver
B. Bad fuser; place service call to printer manufacturer.
C. Excess toner on drum; perform maintenance (e.g. clean drum surface).
D. Deteriorating rollers and worn brushes; replace rollers and brushes.
第8题：
The frequency of an AC generator is controlled by the
A.rheostat
B.governor
C.exciter
D.capacitor
第9题：
At six o-clock she gets up，then brushes her____(tooth)．
第10题：
画笔（Brushes）调板中共包含四种类型的笔刷，下列哪项不包含其中？（）