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
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
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 grease gun is generally used to lubricate a （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.