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 （）.
A pressure drop through the refrigerant liquid line may cause （）.
A grease gun is generally used to lubricate a （）.
The major source of chemical contaminants in hydraulic fluid is （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
A salinity indicator is used to determine the （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Which of the following statements is correct concerning heat transfer?（）
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.