A.unusual vibration
B.excessive worn parts
C.abnormal pressure
D.any of the above
您可能感興趣的試卷
你可能感興趣的試題
A.Relief valve
B.Direction control valve
C.Stop valve
D.Pressure control valve
A.flow of oil
B.pressure of oil
C.A and B
D.temperature of oil
A.Relief valves
B.Check valves
C.Safety valves
D.Reducing valve
A.Hydraulic pumps
B.Valve
C.Hydraulic cylinders
D.Hydraulic motors
A.The hydraulic pumps
B.Valves
C.Hydraulic cylinders
D.Hydraulic motors
最新試題
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
A salinity indicator is used to determine the （）.
Thermostatic expansion valves can be adjusted for （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
A pressure drop through the refrigerant liquid line may cause （）.
The general purpose of a heat exchanger is to （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.