A.maintaining a steadier speed
B.delivering liquids over greater distances
C.operating for longer periods of time
D.producing a smoother discharge flow
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A.rolling member size
B.inner race cone width
C.manufacturers numerical code
D.outer ring width
A.mechanical energy to kinetic energy to potential energy
B.mechanical energy to potential energy to kinetic energy
C.potential energy to mechanical energy to kinetic energy
D.kinetic energy to mechanical energy to potential energy
A.The wearing rings are excessively worn
B.The suction strainer is clogged
C.The discharge valve is clogged
D.The shaft is worn
A.sudden evaporation of wax crystals in the lubricant
B.sudden evaporation of entrapped air in the lubricant
C.release of refrigerant from the oil/refrigerant mixture
D.release of dissolved lubricant from the refrigerant
A.motor overload will open
B.relief valve will open
C.pump will overheat
D.motor will overheat
A.The liquid receiver functions to collect and remove non-condensable gases
B.A thermostatic expansion valve is used to control refrigerated space temperature
C.Refrigerant temperature in an evaporator is directly related to refrigerant pressure
D.Dehydrators must be used continuously in a refrigeration system
A.directly increase the pressure of the liquid being pumped
B.directly increase the velocity of the liquid being pumped
C.convert the potential energy of the liquid to kinetic energy
D.separate air from the liquid being pumped
A.overheated compressor bearings
B.excess lube oil viscosity
C.carbon deposits on the compressor piston rings
D.wax crystals forming in the lubricant
A.electric motor
B.volute
C.impeller
D.diffusion nozzle
A.expansion valve to overfeed
B.compressor to knock
C.water regulating valve to fail
D.crankcase drains to plug
最新试题
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
A salinity indicator is used to determine the （）.
A salinity indicator is used to determine the （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
A pressure drop through the refrigerant liquid line may cause （）.
Thermostatic expansion valves can be adjusted for （）.