单项选择题
A.heat B.power C.horsepower D.foot-pound
Noise in a refrigeration compressor can be caused by （）...
单项选择题Noise in a refrigeration compressor can be caused by （）.
A.worn bearings and piston pins B.slugging due to flooding back C.too much oil in circulation D.All of the above
The air charge leaving an intercooler, or after-cooler ...
单项选择题The air charge leaving an intercooler, or after-cooler of an air compressor can be expected to be （）.
A.superheated B.super-cooled C.at or below the dew point D.All of the above
Before starting a reciprocating, steam-driven pump that...
单项选择题Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.
A.open the steam line mot valve B.drain the steam cylinder C.close the steam cylinder drains D.open the liquid cylinder drains
