单项选择题
A.Needle B.Tapered roller C.Roller D.Ball
Refrigeration system compressor crankcase sweating is a...
单项选择题Refrigeration system compressor crankcase sweating is an indication of （）.
A.insufficient lube oil circulating through the system B.excessive circulation of lube oil through the system C.insufficient refrigerant in the system D.an overworked compressor
Operating a rotary pump at speeds in excess of design r...
单项选择题Operating a rotary pump at speeds in excess of design requirements could cause（）.
A.decreased clearances between rotating parts B.decreased slippage to the suction side of the pump C.air binding in the discharge ports D.erosion and excessive wear
A refrigeration system compressor crankcase is sweating...
单项选择题A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.
A.a shortage of refrigerant in the system B.air in the system C.an accumulation of liquid refrigerant in the crankcase D.a shortage of oil in the crankcase
