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
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
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 （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）