单项选择题
A.second stage cylinder lockup B.oil sump contamination C.faulty operation of pneumatic valves D.corrosion of air receiver baffles
Overheating of a hydraulic system may be a result of （）...
单项选择题Overheating of a hydraulic system may be a result of （）.
A.changing pump discharge pressure in response to normal load variations B.a high oil level C.incorrect fluid viscosity D.continued slow re-circulation of the oil
The purpose of the low pressure cut-out switch is to （）...
单项选择题The purpose of the low pressure cut-out switch is to （）.
A.maintain liquid refrigerant at the suction of the compressor B.maintain a preset suction pressure to the compressor C.start and stop the compressor at preset operating pressures D.operate at minimum efficiency
The process of boiling seawater in order to separate it...
单项选择题The process of boiling seawater in order to separate it into freshwater vapor and brine is usually defined as （）.
A.dehydration B.condensation C.evaporation D.dissolution
