A.insufficient lube oil circulating through the system
B.excessive circulation of lube oil through the system
C.insufficient refrigerant in the system
D.an overworked compressor
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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
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
最新試題
The major source of chemical contaminants in hydraulic fluid is （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
Which of the listed pumps is NOT a positive displacement pump?（）
The usual symptoms of cavitation in a centrifugal pump is （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
Thermostatic expansion valves can be adjusted for （）.