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
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相关考题
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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 -
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 -
单项选择题
In the production of freshwater from seawater through a process of heating and cooling, the cooling phase of production is usually called （）.
A.evaporation
B.distillation
C.dehydration
D.condensation
