单项选择题
A.compressor is overloaded B.motor is overloaded C.foundation bolts are loose D.belts are too tight
The term "pour point" is defined as the lowest temperat...
单项选择题The term "pour point" is defined as the lowest temperature at which lubricating oils will flow （）.
A.rapidly B.by gravity C.through a standard orifice at a specified temperature D.at a rate of 60cc per second
When liquid reaches the compressor of a refrigeration s...
单项选择题When liquid reaches the compressor of a refrigeration system through the suction line, the condition is called （）.
A.flooding back B.superheating C.overflowing D.recycling
What is a function of the wearing rings used in most ce...
单项选择题What is a function of the wearing rings used in most centrifugal pumps?（）
A.Absorb erosion of high velocity discharge stream B.Seal pump shaft against entry of air C.Isolate the discharge side from the suction side D.Dampen the turbulent discharge flow
