A.a shortage of refrigerant in the system
B.air in the system
C.an accumulation of liquid refrigerant in the crankcase
D.a shortage of oil in the crankcase
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A.ram relief valves bypass oil to stop rudder movement
B.six-way valve shifts to the neutral flow position
C.steering pump electric motor is de - energized by the transfer switch
D.follow-up gear takes the hydraulic pump off stroke
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
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.a defective or broken high pressure un-loader
B.a loose valve plate
C.excessive overload
D.no compression
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
最新試題
The output volume of a positive fixed displacement pump can be changed only by （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
A salinity indicator is used to determine the （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
Which of the listed pumps is NOT a positive displacement pump?（）