Wear occurring at the tips of the reduction gear teeth is usually the result of ______.A.surface fatigueB.fretting corrosionC.heavy overloadingD.gear misalignment
Wear occurring at the tips of the reduction gear teeth is usually the result of ______.
A.surface fatigue
B.fretting corrosion
C.heavy overloading
D.gear misalignment
相关考题：
Combustion knock occurring in a diesel engine can be caused by _____.A.low coolant temperatureB.insufficient fuelC.high ambient temperatureD.carbon buildup on the injector tips
When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for workA.remains the sameB.is reducedC.is increasedD.is eliminated
One of the most common causes of reduction gear failure is gear wear caused by scoring as a result ofA.surface fatigue of the gearsB.an inadequate lube oil filmC.plastic flow of the gearsD.fretting corrosion from water
Pitted reduction gear teeth having a deep blue color with evidence of overheating have been operated with _______.A.excessive speedB.improper warm-upC.extreme misalignmentD.inadequate lubrication
第二组：Magnetic pickup (MPU) sensors are devices which can be used in conjunction with electronic control modules for monitoring of parameters such as speed, direction of rotation and a variety of alarm conditions. MPU sensors are available in various sizes and types. Following are some guidelines for their selection on industrial engines. MPUs are located near a flywheel, camshaft or other type of gear with rotation relative to engine speed. The passing of the gear teeth through the MPU tip (pole) generates a voltage and frequency. This frequency is converted to a speed reference by a control module. It should be noted here that most MPUs will develop similar signals. However, the magnitude and strength of the signal is dependent on the size of the sensor in relation to the gear teeth, the clearance between the pole piece and the gear teeth, and various other factors. As a general rule of thumb, the following standards should be met:①Dimension of tooth top surface should be equal to or more than the pole piece diameter.②Tooth height should be equal to, or more than the space between teeth.③The space between teeth should be approximately three times the pole piece diameter.④Air gap (clearance) between tooth and pole piece should be between 0.015 to 0.030. MPUsnormally have 3/8, 5/8 threads and 2, 3 and 4 lengths. Determining which size is appropriatedepends on the space available for installation, the availability of pre-drilled holes and consideration tothose rules mentioned above. In most cases, these will be the only factors affecting the selcetion of aMPU.MPUs can be used to ____.①sense speed ②supply alarm ③sense direction of rotation.A.①②B.②③C.①③D.①②③
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单选题A magnetic strainer is used in the diesel engine reduction gear oil system to remove small particles of（）.AwaterBbabbittCiron or steelDacids
单选题Proper operation of the main engine reduction gear set requires the operation to monitor （）Athe sump oil levelBoil flow sight glassesCbearing temperaturesDall of the above
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单选题Pitting in the area close to the pitch line and on the same end of each gear tooth of a reduction gear unit would be caused by （）Acorrosion on the gearsBexcessive gear speedCdirt in the oilDmisalignment of the gears
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单选题Combustion knock occurring in a diesel engine can be caused by （）Alow coolant temperatureBinsufficient fuelChigh ambient temperatureDcarbon buildup on the injector tips
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单选题Wear occurring at the tips of the reduction gear teeth is usually the result of （）.Asurface fatigueBfretting corrosionCheavy overloadingDgear misalignment
单选题Pitted reduction gear teeth having a deep blue color with evidence of overheating have been operated with （）Aexcessive speedBimproper warm-upCextreme misalignmentDinadequate lubrication
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