单项选择题Crankcase sweating in a refrigeration system is caused by ().

A.a stuck solenoid valve
B.a shortage of refrigerant
C.too much oil in circulation
D.too much superheat


您可能感兴趣的试卷

你可能感兴趣的试题

3.单项选择题An increase in rotor clearances in a rotary pump will ().

A.increase discharge pressure
B.decrease pump capacity
C.decrease pump cavitation
D.decrease reaction ring clearance

4.单项选择题Sweating of the refrigeration system compressor crankcase is caused by ().

A.too much superheat
B.insufficient superheat
C.suction pressure too low
D.excessive refrigerant returning to the compressor

6.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

7.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

8.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

9.单项选择题When the desired rudder angle is attained by a typical double mm electro-hydraulic steering gear,the().

A.ram relief valves bypass oil to stop rudder movement
B.six-way valve shifts to the neutral flow position
C.steering pump electric motor is de - energized by the transfer switch
D.follow-up gear takes the hydraulic pump off stroke

10.单项选择题A swing check valve is used in a pipeline to ().

A.maintain a preset pressure on the line
B.closely regulate the amount of flow
C.relieve excessive pressure on the line
D.allow flow in one direction only