更多"An air compressor can be unloaded a"的相关试题:
[单项选择]A knocking sound emitted from an unloaded air compressor is probably caused by （）.
A. damaged intake valves
B. excessively tight mounting bolts
C. insufficient cylinder lubrication
D. a loose piston
[单项选择]The air compressor pumps air to the （）.
A. air cylinder
B. combustion chamber
C. steam drum
D. expansion tank
[单项选择]The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）
A. system is overcharged with refrigerant
B. system is low on refrigerant
C. discharge valves are leaking excessively
D. discharge valves are leaking slightly
[单项选择]Hot air can hold（）.
A. less moisture than cold air
B. more moisture than cold air
C. the same amount of moisture as cold air
D. moisture independent of air temperature
[单项选择]If an air compressor is used to supply air primarily to the combustion control system and other pneumatic controllers, the entire system is known as the （）.
A. control air system
B. forced draft air system
C. supply air system
D. ships service air system
[单项选择]Noise in a refrigeration compressor can be caused by （）.
A. worn bearings and piston pins
B. slugging due to flooding back
C. too much oil in circulation
D. All of the above
[单项选择]The purpose of an air compressor unloading device is to （）
A. drain water from the air receiver
B. drain water from the cylinders
C. delay the compression process until the motor is up to speed
D. check pump alignment
[单项选择]If the electric motor driving an air compressor fails to start, the cause may be a （）.
A. leaking unloader
B. tripped circuit breaker
C. control line leak
D. defective pop valve
[单项选择]If an electric motor driven air compressor fails to start, it may be due to a （）.
A. leaking discharge valve
B. jammed suction valve
C. tripped overload relay
D. broken discharge un-loader
[单项选择]A dirty intercooler on an air compressor will cause （）.
A. damage to the un-loader operating diaphragm
B. an increase in current flow to the motor
C. high pressure in the receiver and filter
D. an excessive consumption of crankcase oil
[单项选择]If an air compressor is used to supply compressed air to outlets throughout the engine room and on deck of a vessel, the system is known as the （）.
A. combustion control air system
B. supply air system
C. ships service air system
D. low pressure deck air system
[单项选择]Air compressor receivers should be “blown down” at least （）.
A. yearly
B. quarterly
C. monthly
D. daily
[单项选择]During working of an air compressor, （） should be drained.
A. inter cooler
B. cylinder
C. outlet pipe
D. inlet pipe
[单项选择]The unloading system on an air compressor will （）.
A. increase compressor discharge pressure on demand
B. increase compressor operating speed as necessary
C. allow the motor to turn the compressor opposed only by friction
D. reduce the compressor frictional load when starting
[单项选择]The loss of （） from an air compressor could lead to an overheated air discharge and possibly an explosion in the pipelines leading to the air reservoir.
A. lubricating oil
B. compressed air
C. cooling water
D. sealing ring
[单项选择]A reciprocating air compressor is running roughly and vibrating excessively, indicating that the （）.
A. compressor is overloaded
B. motor is overloaded
C. foundation bolts are loose
D. belts are too tight
[单项选择]Air compressor cylinder un-loaders enable the compressor to （）.
A. vary their speed according to temperature and load
B. start and come up to speed before air compression begins
C. change speed according to overload demands
D. reduce compressed air charge density
