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

题目

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

相似考题

1.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

2.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

3.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

4.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

参考答案和解析
正确答案：A
更多“If a reciprocating air compressor has a knock occurring in frequency with its operating RP ”相关问题

  • 第1题：

    单选题
    Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.
    A

    using a slightly dirty air filter

    B

    using oil having an excessive viscosity

    C

    intercooler or after-cooler leaks

    D

    carrying the oil level higher than normal


    正确答案： B
    解析： 暂无解析

  • 第2题：

    单选题
    Air blowing from the intake air filter of an operating air compressor indicates （）.
    A

    broken inlet valves

    B

    broken discharge valves

    C

    pulsations in the air distribution system

    D

    overloading of the air distribution system


    正确答案： A
    解析： 暂无解析

  • 第3题：

    单选题
    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


    正确答案： C
    解析： 暂无解析

  • 第4题：

    单选题
    Sludge may form in the crankcase of an air conditioning compressor as a result of （）.
    A

    bubbling refrigerant

    B

    overheating and oxidation

    C

    lowered operating temperatures

    D

    reducing the cloud or flash point


    正确答案： A
    解析： 暂无解析

  • 第5题：

    单选题
    （）are supplied by main switchboard directly.
    A

    Suez Canal searchlight, air compressor and air conditioning compressor

    B

    Air compressor, boiler blower and refrigeration plant

    C

    Boiler blower, Suez Canal searchlight and refrigeration plant

    D

    Suez canal searchlight, air compressor and boiler blower


    正确答案： C
    解析： 暂无解析

  • 第6题：

    单选题
    Broken valve strips in an operating low pressure, air compressor will cause （）.
    A

    an immediate crankcase explosion

    B

    oil contamination in the compressed air

    C

    a decrease in compressor capacity

    D

    no immediate loss of the compressed air capacity


    正确答案： A
    解析： 暂无解析

  • 第7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 coil

    B

    increasing chilled water flow through the cooler

    C

    sub-cooling the refrigerant in the condenser

    D

    superheating the refrigerant in the compressor


    正确答案： C
    解析： 暂无解析

  • 第8题：

    单选题
    The air compressor pumps air to the（）.
    A

    engine cylinder

    B

    air bottle

    C

    evaporator

    D

    condenser


    正确答案： B
    解析： 暂无解析

  • 第9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 bearings

    B

    insufficient cylinder lubrication

    C

    defective or poorly fitted valves

    D

    all of the above


    正确答案： A
    解析： 暂无解析

  • 第10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 temperature

    B

    low firing pressure

    C

    fuel knock in each cylinder

    D

    mechanical knock in each cylinder


    正确答案： C
    解析： 暂无解析

  • 第11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

    just

    B

    nearly

    C

    merely

    D

    already


    正确答案： A
    解析： 暂无解析

  • 第12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 belt

    B

    Faulty operation of a cylinder un-loader

    C

    Compressor operation in an area of high relative humidity

    D

    Lifting of intercooler rebel valve


    正确答案： D
    解析： 暂无解析

  • 第13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 lubricant

    B

    sudden evaporation of entrapped air in the lubricant

    C

    release of refrigerant from the oil/refrigerant mixture

    D

    release of dissolved lubricant from the refrigerant


    正确答案： B
    解析： 暂无解析

  • 第14题：

    单选题
    Air France carries out its Frequency Plus _____.
    A

    through its reduced ticket prices

    B

    through its extensive network of partners

    C

    by providing convenient flight schedules

    D

    by offering excellent services on board


    正确答案： D
    解析：
    根据文章的首句话可以找到关键信息“Air France offers you Frequency Plus through an extensive network of our partners”，法航通过广泛的合作商网络实施的常旅客里程奖励计划，选项B是原文的直接引述，是正确答案。A项断章取义，文中提到了奖励计划，但是这不是为了降低票价，与题目要求无关。C项和D项均属于无中生有，文中都没有涉及这两个选项。

  • 第15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 springs

    B

    tight drive belts

    C

    high line voltage

    D

    air in the system


    正确答案： A
    解析： 暂无解析

  • 第16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 timing

    B

    caused by a mechanical defect in one cylinder

    C

    caused by high fuel injection pressures

    D

    normal for these conditions


    正确答案： B
    解析： 暂无解析

  • 第17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

    BDC

    B

    TDC

    C

    BBDC

    D

    ATDC


    正确答案： A
    解析： 暂无解析

  • 第18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 compressor

    B

    The temperature of the air entering the compressor

    C

    The designed rotating speed of the compressor

    D

    A leaking head gasket


    正确答案： C
    解析： 暂无解析

  • 第19题：

    单选题
    A knocking sound from one cylinder of an operating air compressor indicates （）.
    A

    a defective or broken high pressure un-loader

    B

    a loose valve plate

    C

    excessive overload

    D

    no compression


    正确答案： D
    解析： 暂无解析

  • 第20题：

    单选题
    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


    正确答案： A
    解析： 暂无解析

  • 第21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 oil

    B

    contamination by dust, scale, or moisture

    C

    refrigerant bubbles in the lube oil

    D

    refrigerant reducing the lube oil viscosity


    正确答案： D
    解析： 暂无解析

  • 第22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 oil

    B

    refrigerant reducing the lube oil viscosity

    C

    oxidation of the lube oil from overheating

    D

    reducing the floc or cloud point of the oil


    正确答案： D
    解析： 暂无解析

  • 第23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 cylinder

    B

    leaky discharge valves on the HP cylinder

    C

    insufficient intercooler cooling

    D

    low ambient air pressure


    正确答案： C
    解析： 暂无解析

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