网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
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
参考答案
更多 “ 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 ” 相关考题
考题
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
考题
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(氧化) of the lube oil from overheatingD.reducing the floc or cloud point of the oil
考题
Sludge may form in the crankcase of an air conditioning compressor as a result of ______.A.bubbling refrigerantB.overheating and oxidationC.lowered operating temperaturesD.reducing the cloud or floc point
考题
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
考题
单选题Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.A
using a slightly dirty air filterB
using oil having an excessive viscosityC
intercooler or after-cooler leaksD
carrying the oil level higher than normal
考题
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
考题
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
考题
单选题Air France carries out its Frequency Plus _____.A
through its reduced ticket pricesB
through its extensive network of partnersC
by providing convenient flight schedulesD
by offering excellent services on board
考题
单选题The unloading system on an air compressor will （）.A
increase compressor discharge pressure on demandB
increase compressor operating speed as necessaryC
allow the motor to turn the compressor opposed only by frictionD
reduce the compressor frictional load when starting
考题
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
考题
单选题Sludge may form in the crankcase of an air conditioning compressor as a result of （）.A
bubbling refrigerantB
overheating and oxidationC
lowered operating temperaturesD
reducing the cloud or flash point
考题
单选题The knock occurring when a cold diesel engine is started and continues while running at low speed, but stops when the engine reaches normal operating speed and temperature, is（）.A
caused by retarded injection timingB
caused by a mechanical defect in one cylinderC
caused by high fuel injection pressuresD
normal for these conditions
考题
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
考题
单选题The compressed air is admitted to each cylinder through a cam operated by starting air valve when the piston has just passed its （）.A
BDCB
TDCC
BBDCD
ATDC
考题
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
考题
单选题A knocking sound from one cylinder of an operating air compressor indicates （）.A
a defective or broken high pressure un-loaderB
a loose valve plateC
excessive overloadD
no compression
考题
单选题The air compressor pumps air to the（）.A
engine cylinderB
air bottleC
evaporatorD
condenser
考题
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
考题
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 bearingsB
insufficient cylinder lubricationC
defective or poorly fitted valvesD
all of the above
考题
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
考题
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
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When the starting air valve closes on one cylinder, another starting air valve has （） opened on another cylinder whose piston has just commenced its downward stroke.A
justB
nearlyC
merelyD
already
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
low ambient air pressure
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
热门标签
最新试卷