单项选择题
Brushless generators are designed to operate without the use of（）.
A.brushes
B.slip rings
C.commutators
D.all of the above
点击查看答案&解析
相关考题
-
单项选择题
It （） for an emergency generator to require paralleling.
A.is usual
B.is not usual
C.is necessary
D.is not impossible -
单项选择题
Usually the panels are interlocked with （） so that the devices can be made dead before the doors are opened.
A.protective earth
B.isolators
C.ground switch
D.circuit-breakers -
单项选择题
In （） the control action is independent on(of) the output.
A.a closed loop control system
B.an open loop control system
C.a boiler control system
D.a steering gear control system
