A.The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow
B.The pump packing gland overheats after short operating periods
C.The motor over-current protective device continually shuts the pump down
D.Pounding noises can be heard at the pump suction chest
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A.diameter of the discharge piping, with all other factors remaining the same
B.diameter of the suction piping, with all other factors remaining the same
C.width of the impeller only
D.diameter of the impeller
A.run continuously
B.not start
C.have high discharge pressure
D.short cycle on the high pressure switch
A.Electrical energy
B.Thermal energy
C.Potential energy
D.Kinetic energy
A.sliding block
B.pintle
C.reaction ring
D.tilting box or swash plate
A.overfeeding of the expansion valve
B.damage to the condenser
C.constant running of the compressor
D.flooding of the receiver
最新試題
Low compressor head pressure in a refrigeration system can be caused by（）.
The major source of chemical contaminants in hydraulic fluid is （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
The general purpose of a heat exchanger is to （）.
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 （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.