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单选题
The pumps press oil into the cross-head bearing gap when the load on the shell is at its lowest What is the meaning of “its” in the sentence above?（）
A
the cross-head
B
the pumps
C
the shell
D
the load
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更多 “单选题The pumps press oil into the cross-head bearing gap when the load on the shell is at its lowest What is the meaning of “its” in the sentence above?（）A the cross-headB the pumpsC the shellD the load” 相关考题
考题
Which of the following statements concerning the lubrication of diesel propulsionengines used in vessels over 300 gross tons is most accurate? ( )A.Lubrication systems using engine driven lube oil pumps do not require any additionalindependent arrangement when such arrangements have been proven reliable.B.The use of engine driven pre-lube pumps is permitted on vessels with propulsionsystems developing less than 500 shaft horsepower.C.When forced lubrication is used for propulsion engines , one independently drivenstandby pumps is to be provided in addition to the necessary pumps for normaloperation.D.Lubrication systems where two oil coolers are fitted require a minimum of twotemperature control devices which may be actuated by similar sensors.
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In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a drilled passage in the crankshaft to the bottom end bearing and then up a connection rod to theA.crossheadB.crankpinC.crank journalD.gudgeon pin
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Lubrication for the main reduction gears used with diesel engines is usually supplied byA.oil from the main engine sumpB.an independent lube oil systemC.the stern bearing head tankD.the stem bearing sump tank
考题
Adjust ______by means of lead wire.A.the clearance of the main bearingB.the diameter of main bearingC.the gap of main bearingD.the tolerance of main bearing
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材料：Spark erosion is caused by a voltage discharge between the main bearing and journal surface. The cause of the potential is the development of a galvanic element between the ship’s hull, sea water, and the propeller shaft/crankshaft.The oil film acts as a dielectric. The puncture voltage in the bearing depends on the thickness of the oil film. With increasing engine ratings, the specific load in the main bearing is increased. his will reduce the oil film thickness, and enable the discharge to take place at a lower voltage level.Since the hydrodynamic oil film thickness varies through a rotation cycle, the discharge will take place at roughly the same instant during each rotation cycle, i.e. when the film thickness is at its minimum. The roughening will accordingly be concentrated in certain areas on the journal surface. In the early stages, the roughened areas can resemble pitting erosion. but later, as the roughness increases, the small craters will scrape off and pick up white metal-hence the silvery white appearance.Therefore, to ensure protection against spark erosion, the potential level must be kept at maximum 80 mV, which is feasible today with a high efficiency earthing device. If an earthing device is installed, its effectiveness must be checked regularly. Spark erosion is only observed in main bearings and main bearing journals.问题：According to the paragraph one, a voltage between the main bearing and journal surface is produced by______.A.propeller rotationB.leakage from M/E electric control unitC.a galvanic elementD.friction between the main bearing and journal surface______engine ratings increase, the hydrodynamic oil film between the main bearing and journal surface is______.A.The lower/thinnerB.The higher/the thickerC.The lower/thickerD.The higher/thinnerWhen will the spark erosion take place on the journal surface during each rotation cycle?A.when the film thickness is at its minimumB.when the film thickness is at its maximumC.when the engine is on its compression strokeD.when the engine is on its exhaust strokeDuring the engine room watch keeping, which equipment must be noted to ensure protection against spark erosion?A.the antifouling plantB.the earthing deviceC.the main engine electric heating coilsD.the shaft generator请帮忙给出每个问题的正确答案和分析，谢谢！
考题
Which statement is TRUE concerning deep well self-priming pumps ________．A.When loading oil cargo，it is always loaded via the discharge line through to the pump until the tank is topped offB.Stripping systems are generally eliminated for the purposes of cargo handlingC.In recent years deep well pumps have become increasingly unpopular in product tankers and medium size crude shipsD.There is no danger of damaging the pump from overheating
考题
You are on a tanker discharging oil．When all of the oil that the main cargo pumps can handle is pumped out of a tank，the remainder is ______．A.Stripped out and pumped directly ashore into the mainline as the remaining cargo tanks are pumped out with the main pumpsB.Stripped to one tank and then pumped out with the main pumpsC.Stripped out and pumped directly ashore after all the tanks have been emptied by the main pumpsD.Gravitated to the centers from the wings and pumped out with the main pumps
考题
单选题A dirty lube oil strainer can result in（）A
crankcaseB
low lube oil temperatureC
excessive oil consumptionD
low bearing oil pressure
考题
单选题In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a drilled passage in the crankshaft to the bottom end bearing and then up a connection rod to the （）.A
crossheadB
crankpinC
crank journalD
gudgeon pin
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单选题Thermocouple pyrometers are used on large, main propulsion diesel engines to indicate the temperature of the（）A
cooling water leaving each cylinderB
fuel oil entering the injectorC
exhaust gases at various locationsD
lube oil at the bearing supplies
考题
单选题The purpose of an oil mist detector in a main propulsion diesel engine is to warn of （）A
excessive mist density in the crankcasesB
excessively high crankcase vacuumC
excessively high bearing temperatureD
excessive carbon buildup in the lube oil
考题
单选题A vessel has been equipped with an oil lubricated stern bearing and is undergoing a routine dry-dock.Which of the following inspection should be made when the tail-shaft has been drawn?（）A
The overall condition of the bearing surface should be examinedB
The shaft liner should be inspected for cracks and tested to insure a tight fitC
The stern tube should be tested for cracks with dye penetrantD
all of above
考题
单选题The oil pressure and flow from each bearings can be checked when（）A
the lubricating pumps are stopped and the access doors are openedB
the lubricating pumps are running and the access doors are openedC
the engine is running and the access doors are closedD
the engine is stopped and the access doors are closed
考题
单选题Two main lubricating oil pumps are usual and are obligatory in （）.A
container shipsB
bulk carriersC
passenger shipsD
barges
考题
单选题Machinery driving fuel oil transfer and fuel oil service pumps must be fitted with a remote means of stopping the machinery from （）.A
within the space concernedB
outside the space concernedC
the throttle stationD
within the fire room
考题
单选题Measure （） by means of lead wire.A
the clearance of the main bearingB
the play of the miler bearingC
the gap of the main bearingD
the tolerance of the main bearing
考题
单选题The bearing shell generally has （） for location and oil grooves round the center of its axial length.A
tipsB
tagsC
lipsD
keys
考题
单选题The pumps press oil into the cross-head bearing gap when the load on the shell is at its lowest What is the meaning of “its” in the sentence above?（）A
the cross-headB
the pumpsC
the shellD
the load
考题
单选题When the bearing becomes dry from lack of oil, the motor shaft may heat to （）an extent （） it welds itself to the bearing.A
either；orB
neither；norC
such；thatD
so；that
考题
单选题Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the （）A
electronic ignition systemB
compression of air by the pistonC
friction in the fuel injectorD
fuel oil bearing system
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Which of the following statements concerning the lubrication of diesel propulsion engines used in vessels over 300 gross tons is most accurate?（）A
Lubrication systems using engine driven lube oil pumps do not require any additional independent arrangement when such arrangements have been proven reliableB
The use of engine driven pre-lube pumps is permitted on vessels with propulsion systems developing less than 500 shaft horsepowerC
When forced lubrication is used for propulsion engines, one independently driven stand-by pumps is to be provided in addition to the necessary pumps for normal operationD
Lubrication systems where two oil coolers are fitted require a minimum of two temperature control devices which may be actuated by similar sensors
考题
单选题The bearing cap and shell are replaced and tightened up until （）.A
the “ nip ”is zeroB
the “ nap ” is zeroC
the “ gap ”is correctD
the “ clearance ” is correct
考题
单选题The function of lubricating oil is to （）.A
reduce friction between moving surfacesB
provide even distribution of bearing wearC
reduce the accumulation of harmful detergentsD
maintain a constant oil temperature output at each beating
考题
单选题High lube oil temperatures developing in a diesel engine can result from（）A
high oil pressureB
excessive bearing end playC
plugged oil control ringsD
engine overload
考题
单选题While inspecting the main bearings on a diesel engine you find impregnated dirt and scratches in the bearing surface you would, therefore, suspect that （）A
the bearing had been overheatedB
water was present in the oilC
the lube oil was not being properly filteredD
the maximum allowable bearing pressure had been exceeded
考题
单选题Lubricating oil used in a diesel engine serves to（）A
reduce the wear of bearing surfacesB
cool the bearing surfacesC
assist in sealing bearing surfacesD
all of the above
考题
单选题Fuel oil transfer systems used onboard diesel propelled vessels are required to have （）.A
two fuel oil transfer pumps provided where one is to be independent of the main engineB
two fuel oil transfer pumps, with a combined capacity exceeding the maximum consumption of the main engineC
engine driven transfer pumps and only used in constant speed applicationsD
the capacity of the engine driven pump exceed the consumption rate of the engine to which it is attached
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