单项选择题
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
单项选择题 Increasing the speed of a centrifugal pump will result in an increase in its capacity Another means of increasing the capacity of a centrifugal pump is to increase the （）.
单项选择题 If the discharge valves on a refrigeration compressor are leaking badly, the compressor should （）.
单项选择题 Which of the following terms could be applied to the simple definition the energy of motion?（）