单项选择题
A.maintain a preset pressure on the line B.closely regulate the amount of flow C.relieve excessive pressure on the line D.allow flow in one direction only
Sluggish response or action of the hydraulic actuators ...
单项选择题Sluggish response or action of the hydraulic actuators may be a result of （）.
A.insufficient load B.excessively high oil viscosity C.relief-valve pressure setting too high D.reservoir level being maintained two inches above normal
A knocking sound from one cylinder of an operating air ...
单项选择题A knocking sound from one cylinder of an operating air compressor indicates （）.
A.a defective or broken high pressure un-loader B.a loose valve plate C.excessive overload D.no compression
Rotation of the steering wheel on the navigation bridge...
单项选择题Rotation of the steering wheel on the navigation bridge initiates oil pressure being applied to the steering gear rams by （）.
A.regulating the oil flow with the six-way valve B.moving the automatic differential valve C.moving the receiving tele-motor which regulates the two-way valve D.varying the angle of a tilting box or eccentricity of a floating ring
