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）
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
参考答案
更多 “ Wear occurring at the tips of the reduction gear teeth is usually the result of ______.A.surface fatigueB.fretting corrosionC.heavy overloadingD.gear misalignment ” 相关考题
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
考题
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
考题
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
考题
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
考题
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
考题
Brides usually wear white wedding dresses，because white______ purity．A．stands forB．stands outC．stands upD．stands by
考题
Chafing gear ______.A.reduces and prevents corrosion of standing riggingB.prevents corrosion of running riggingC.reduces and prevents wear caused by the rubbing of one object against anotherD.protects the body against extreme cold
考题
Usually the Charterer has to redeliver the ship in the same good order ______ when delivered，fair wear and tear excepted．A.inB.byC.onD.as
考题
I rarely wear a raincoat because I spend most of my time in a car.A:normally B:seldom C:frequently D:usually
考题
单选题What is the function of the thrust bearing?（）A
Prevents lateral movement of the slow speed gearB
Transmits propeller thrust to the hullC
Keeps spring bearings in lineD
Prevents main reduction gear axial movement
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When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for work （）A
remains the sameB
is reducedC
is increasedD
is eliminated
考题
单选题A magnetic strainer is used in the diesel engine reduction gear oil system to remove small particles of（）.A
waterB
babbittC
iron or steelD
acids
考题
单选题Proper operation of the main engine reduction gear set requires the operation to monitor （）A
the sump oil levelB
oil flow sight glassesC
bearing temperaturesD
all of the above
考题
单选题Where are the test certificates，for wire rope used as cargo runners，and loose gear certificates usually maintained? （）A
With the Cargo Gear Register on the shipB
In the Official LogC
At the Coast Guard Marine Safety Office with the vessel's inspection recordsD
At the central records center of the agency testing the cargo gear
考题
单选题On your vessel，a wire rope for the cargo gear shows signs of excessive wear and must be replaced. In ordering a new wire for this 10-ton boom，what safety factor should you use?（）A
ThreeB
FiveC
SixD
Seven
考题
单选题Positive displacement, helical gear pumps are well suited for pumping oil because （）A
stuffing boxes eliminate the leakage problems usually associated with other gear pumpsB
it is not necessary to closely maintain design clearances with this pumpC
they are essentially self-priming and produce a high suction liftD
these pumps are designed with extreme tooth angled
考题
单选题Chafing gear（）.A
reduces and prevents corrosion of standing riggingB
prevents corrosion of running riggingC
reduces and prevents wear caused by the rubbing of one object against anotherD
protects the body against extreme cold
考题
单选题To absorb the wear resulting from impeller rotation and abrasives in the liquid, a centrifugal pump is usually fitted with （）.A
lantern ringsB
bearingsC
easing volutesD
wearing rings
考题
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 （）A
corrosion on the gearsB
excessive gear speedC
dirt in the oilD
misalignment of the gears
考题
单选题Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）A
must churn the oil in the sumpB
is connected to the propeller shaftC
is driven at the highest RPMD
compensates for alignment variations between the engine and pinion gear
考题
单选题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
考题
单选题To guarantee that a reduction gear bearing is receiving proper oil supply, you should check the （）A
lube oil temperature at the cooler outletB
lube oil strainer magnets bearingC
lube oil temperatureD
lube oil pressure to the bearing
考题
单选题Wear occurring at the tips of the reduction gear teeth is usually the result of （）.A
surface fatigueB
fretting corrosionC
heavy overloadingD
gear misalignment
考题
单选题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
考题
单选题The majority of cargo gear breakdowns are a result of（）.A
Guy failuresB
Topping lift failuresC
Bending of the boom from compressionD
Gooseneck failure
考题
单选题In an electro-hydraulic steering gear, any change in relative position between the synchronous receiver and the follow-up gear will result in（）A
the pump going to full strokeB
closing of the six-way valveC
driving the rams up against the stopsD
a corresponding slowing or increasing of the pumped flow rate
热门标签
最新试卷