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 grease gun is generally used to lubricate a （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A pressure drop through the refrigerant liquid line may cause （）.
Thermostatic expansion valves can be adjusted for （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
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 （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
Which of the following statements is correct concerning heat transfer?（）