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单选题
If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably （）.
A
misalignment or worn main bearings
B
insufficient cylinder lubrication
C
defective or poorly fitted valves
D
all of the above
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If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably _____.A.misalignment or worn main bearingsB.insufficient cylinder lubricationC.defective or poorly fitted valvesD.All of the above
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In a chilled(冷的) water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by ______.A.increasing refrigerant pressure in the coilB.increasing chilled water flow through the coolerC.sub-cooling the refrigerant in the condenserD.superheating the refrigerant in the compressor
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Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of ______.A.refrigerant bubbles in the lube oilB.refrigerant reducing the lube oil viscosityC.oxidation(氧化) of the lube oil from overheatingD.reducing the floc or cloud point of the oil
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What is the most probable cause of reduced capacity in a reciprocating air compressor ________．A.Carbon on cylinder headsB.Faulty unloaderC.Leaking air valvesD.Plugged air cooler
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单选题Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.A
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using oil having an excessive viscosityC
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carrying the oil level higher than normal
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单选题The sudden reduction of pressure occurring within the crankcase of a refrigeration compressor during starting causes the （）.A
sudden evaporation of wax crystals in the lubricantB
sudden evaporation of entrapped air in the lubricantC
release of refrigerant from the oil/refrigerant mixtureD
release of dissolved lubricant from the refrigerant
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单选题Air blowing from the intake air filter of an operating air compressor indicates （）.A
broken inlet valvesB
broken discharge valvesC
pulsations in the air distribution systemD
overloading of the air distribution system
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单选题The unloading system on an air compressor will （）.A
increase compressor discharge pressure on demandB
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allow the motor to turn the compressor opposed only by frictionD
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单选题In an air conditioning system, low head pressure associated with a reciprocating compressor can be the result of （）A
broken valve springsB
tight drive beltsC
high line voltageD
air in the system
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单选题（）are supplied by main switchboard directly.A
Suez Canal searchlight, air compressor and air conditioning compressorB
Air compressor, boiler blower and refrigeration plantC
Boiler blower, Suez Canal searchlight and refrigeration plantD
Suez canal searchlight, air compressor and boiler blower
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单选题Broken valve strips in an operating low pressure, air compressor will cause （）.A
an immediate crankcase explosionB
oil contamination in the compressed airC
a decrease in compressor capacityD
no immediate loss of the compressed air capacity
考题
单选题Which of the listed operating conditions would have the greatest effect on the volumetric efficiency of an operating reciprocating air compressor?（）A
The density of the air entering the compressorB
The temperature of the air entering the compressorC
The designed rotating speed of the compressorD
A leaking head gasket
考题
单选题In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by （）.A
increasing refrigerant pressure in the coilB
increasing chilled water flow through the coolerC
sub-cooling the refrigerant in the condenserD
superheating the refrigerant in the compressor
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单选题The air compressor pumps air to the （）.A
expansion tankB
combustion chamberC
air receiverD
evaporator
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单选题The air compressor pumps air to the （）.A
air cylinderB
combustion chamberC
steam drumD
expansion tank
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单选题The air compressor pumps air to the（）.A
engine cylinderB
air bottleC
evaporatorD
condenser
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单选题The air filter is fixed in the （） of an air compressor.A
inlet pipeB
outlet pipeC
inter coolerD
after cooler
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单选题A reciprocating air compressor is running roughly and vibrating excessively, indicating that the （）.A
compressor is overloadedB
motor is overloadedC
foundation bolts are looseD
belts are too tight
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low coolant temperatureB
insufficient fuelC
high ambient temperatureD
carbon buildup on the injector tips
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单选题Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of （）.A
wax precipitation in the lube oilB
contamination by dust, scale, or moistureC
refrigerant bubbles in the lube oilD
refrigerant reducing the lube oil viscosity
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单选题Late fuel injection occurring at, or after TDC in a diesel engine is indicated by excessive exhaust smoke and （）A
low exhaust temperatureB
low firing pressureC
fuel knock in each cylinderD
mechanical knock in each cylinder
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单选题Air compressor cylinder un-loaders enable the compressor to （）.A
vary their speed according to temperature and loadB
start and come up to speed before air compression beginsC
change speed according to overload demandsD
reduce compressed air charge density
考题
单选题Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of （）A
refrigerant bubbles in the lube oilB
refrigerant reducing the lube oil viscosityC
oxidation of the lube oil from overheatingD
reducing the floc or cloud point of the oil
考题
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.A
leaky discharge valves on the LP cylinderB
leaky discharge valves on the HP cylinderC
insufficient intercooler coolingD
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考题
单选题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 systemB
forced draft air systemC
supply air systemD
ships service air system
考题
单选题Which of the following problems would be the probable cause for the faulty operation of a reciprocating air compressor suction valve?（）A
Carbon build up in the piston ring beltB
Faulty operation of a cylinder un-loaderC
Compressor operation in an area of high relative humidityD
Lifting of intercooler rebel valve
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