contaminated fluid
pitted thrust rings
worn pintle bearings
obstructed suctions passage
第1题：
Leakage of hydraulic fluid from around the shaft of a hydraulic motor may be caused by ______.
A.permanent loss of pump suction
B.worn shaft seals
C.high level in the oil sump
D.low motor RPM
第2题：
If one hydraulic pump of an electro-hydraulic steering unit fails, the vessel’s steering can be initially and best maintained by using the ______.
A.trick wheel
B.accumulator
C.standby pump
D.Telemotor
第3题：
The delivery rate of an axial piston hydraulic pump is controlled by varying the position of the
A.tilting box
B.slide block
C.pintle
D.reaction ring
第4题：
reduce radial thrust to the impeller
double the liquid velocity through the pump when compared to a single volute
reduce hydraulic end thrust
provide the effect of multi-staging
第5题：
lobe type
screw type
axial piston type
volute type
第6题：
A centrifugal pump may fail to deliver water when first started if the ______.
A.water seal pipe is plugged
B.pump is not primed
C.seal ring is properly located
D.impeller is flooded
第7题：
excessive drive motor speed
excessive pump discharge pressure
too low of a tilting box angle
insufficient drive motor speed
第8题：
If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause may be ______.
A.high steam pressure in the boiler
B.abnormally high feed-water temperature
C.abnormally high boiler water temperature
D.steam demand exceeding feed pump capacity
第9题：
pump bearings in poor condition
excessively worn actuator-piston packing
broken directional control valve centering springs
low hydraulic oil viscosity
第10题：
a variable displacement axial piston pump
a constant displacement axial piston pump
a reciprocating piston pump
a centrifugal pump