A.decreased clearances between rotating parts
B.decreased slippage to the suction side of the pump
C.air binding in the discharge ports
D.erosion and excessive wear
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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
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
最新試題
A salinity indicator is used to determine the （）.
A pressure drop through the refrigerant liquid line may cause （）.
The general purpose of a heat exchanger is to （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
A salinity indicator is used to determine the （）.
When the steering gear is in operation, you should （）.
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 （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）