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80 4th Class Power Engineering Unit B1:
Lubrication and Bearings Review Quiz
Questions
The best way to clean a bearing is: Select one: a. to send it to the manufacturer b. to acid clean it c. to first remove it from the machine d. to vacuum it - โ โ c This number indicates the acidity of an oil: Select one: a. pH b. acidity c. alkalinity d. neutralization - โ โ d This type of thrust bearing does not utilize an "oil wedge": Select one: a. Mitchell type b. collar type c. flotation type d. Kingsbury type - โ โ b
Three causes of oil related bearing failure are, excessive oil temperature, loss of oil, and: Select one: a. improper oil selection b. poor refining processes c. relying on an automatic oil feeder d. no extreme pressure additive in the oil - โ โ a To ease installation of a bearing on a shaft, the bearing: Select one: a. is greased b. may be sub-cooled c. may be pressed onto the shaft d. may be heated - โ โ d Using pressurized air to blow out a cleaned bearing: Select one: a. should only be done when ventilation is maximum b. must be done only while the bearing is hot c. will cause the bearing to become damaged d. requires high pressure air - โ โ c The characteristics of a good grease are largely determined by: Select one: a. its thickening agent b. its consistency
A generally accepted maximum bearing temperature operating range is: Select one: a. 150 to 165 ยฐC b. 120 to 255 ยฐC c. 25 to 50 ยฐC d. 65 to 70 ยฐC - โ โ d A large journal bearing which is running hotter than normal can be cooled by: Select one: a. Direct application of cool water b. Loosening the bearing caps c. Decreasing the viscosity of the oil by cooling it d. pumping additional grease into it - โ โ A turbine oil should not: Select one: a. be easy to wash off turbine parts b. be prone to leakage c. flow easily d. mix readily with water - โ โ d Air compressor oil should: Select one: a. have a very low viscosity
b. have low carbon residue c. have a low flash point d. not contain anti-oxidants - โ โ b Aluminum based greases canสผt be used in high speed applications because: Select one: a. they remove too much heat b. they tend to soften and melt c. they have high internal friction d. they donสผt stick well to components - โ โ c At elevated temperatures oil can evaporate, which causes it to: Select one: a. separate b. thicken c. burn d. corrode - โ โ b A material which is commonly used as a solid lubricant is: Select one: a. tallow b. wax c. lime d. molybdenum disulphide - โ โ d A ring type oil system uses:
d. should rotate in the opposite direction to the shaft - โ โ b Bearing failure might be caused by: Select one: a. improper brand of bearings b. bearings that must be pressed onto a shaft c. heating the bearings to install them d. high oil temperature - โ โ d Bearing seals are designed to keep foreign material out of the bearing and: Select one: a. keep the lubricant in b. to cool the bearing c. to keep the bearing watertight d. ease the installation process - โ โ a An anti-friction bearing: Select one: a. could be a type of thrust bearing b. is a bearing containing white-metal alloy c. is a sleeve bearing d. receives larger amounts of oil - โ โ a An oil with a low viscosity index: Select one:
a. is a very thin oil, which does not change viscosity with temperature change b. is a very thick oil, which does not change viscosity with temperature change c. goes through a large change in viscosity when subject to temperature change. d. goes through a small change in viscosity when subject to temperature change. - โ โ c Applying installation forces through the balls of a bearing can cause: Select one: a. bearing misalignment b. false brinelling c. cracking or breaking of the balls d. brinelling - โ โ d Besides physically removing heat from a component, how does oil reduce the heat in a bearing?: Select one: a. it reduces the specific heat of the air in the bearing housing b. it reduces wear c. it increases the heat transfer d. it reduces friction - โ โ d Boundary lubrication is characterized by: Select one:
Grease is not a suitable lubricant: Select one: a. If the atmosphere contains a lot of moisture b. When the atmosphere is dusty c. If corrosion protection is desired during downtime d. If a large amount of cooling is desired - โ โ d Grease is the preferred bearing lubricant when speeds are moderate and: Select one: a. wear must be reduced b. the bearing must be sealed against atmospheric contaminants c. the lubricant must be continually replaced d. cooling is a high priority - โ โ b Boundary lubrication occurs when lubricant supply is restricted or: Select one: a. when shaft speed is high b. when the oil is too cold c. when the lubricant supply is intermittent d. if shaft movement varies axially - โ โ c During the starting or stopping portion of a machineryสผs operation, what type of lubrication occurs?: Select one: a. Fluid Film
b. Complete separation c. Boundary d. Positive - โ โ c What problem can arise from adding too much grease to a bearing?: Select one: a. the bearing can be sub-cooled b. the bearing rolling elements can be displaced c. the bearing races can be broken d. the bearing can overheat - โ โ d What purpose does lubrication NOT fulfill?: Select one: a. wear reduction b. friction reduction c. corrosion enhancement d. temperature control - โ โ c What type of bearings are Kingsbury and Mitchell thrust bearings?: Select one: a. anti-friction bearings b. collar thrust bearings c. sleeve bearings d. tilting pad thrust bearings - โ โ d What type of oil do open gears require?:
b. high pour point c. high carbon residue d. high viscosity index - โ โ a If you desire an oil to flow at a much lower temperature you would most likely add: Select one: a. a viscosity index improver b. pour point depressants c. a dispersant d. a low viscosity oil - โ โ b A collar thrust bearing: Select one: a. can support more load than a Mitchell thrust bearing b. can prevent a rotating shaft from moving both axial directions c. uses the fluid film lubrication principle d. is an anti-friction type bearing - โ โ b Some bearing may require heating before installation on a shaft. Which of the following methods of heating are NOT acceptable methods of applying heat to a bearing?: Select one: a. an oil bath b. a propane torch c. an induction heater
d. a specialized hotplate - โ โ b The lowest temperature at which an oil will flow is known as the: Select one: a. gel point b. freeze point c. flow point d. pour point - โ โ d The rolling elements of an anti-friction bearing travel in between two: Select one: a. paths b. orbits c. tracks d. races - โ โ d The separation of two surfaces, which is brought about by an interposing liquid, is called Select one: a. lubrication b. viscosity index c. floc point d. oil flooding - โ โ a The type of grease used for heavily loaded machinery operating at slow speeds is:
c. Poor installation d. Cracked races - โ โ b This class of liquid lubricant is suitable for high temperatures and is resistant to sludge formation and oxidation: Select one: a. synthetic oils b. mineral oils c. fixed oils d. mixed oils - โ โ a This commonly used instrument measures the viscosity of an oil: Select one: a. a Braxton shear-resistance meter b. a Saybolt viscosity meter c. a Partition load cell d. an internal resistance scale - โ โ b Which type of grease is the cheapest and most commonly used?: Select one: a. lithium based grease b. teflon based grease c. paraffin based grease d. calcium (lime) based grease - โ โ d Wear between two surfaces:
Select one: a. is sometimes beneficial b. must always be eliminated c. can always be eliminated d. is sped up with lubrication - โ โ a What could an abnormal sound and a rise above normal operating temperature indicate in a bearing? Select one: a. misalignment b. the bearing is failing c. the lubricant is too hot d. the lubricant is dirty - โ โ b Why arenสผt oil grooves located in the pressure zone of a shell bearing?: Select one: a. the grooves can erode in this area b. the grooves must align with the oil delivery port c. the pressure is too high in the pressure zone to enable effective lubrication d. grooves in this area can disrupt the oil film and cause damage - โ โ d Why is Babbitt such a good metal to use in shell bearings? Select one: a. it is cheap
d. 3โ4 - โ โ b When greasing a bearing, care must be taken to: Select one: a. select the proper grease b. fill the bearing completely with grease c. only add grease when the bearing is cold d. remove the bearing from the machine prior to adding grease - โ โ a When replacing or removing an antifriction ball bearing, the applied force should: Select one: a. only be applied to the press fit race b. always be against the inner race c. always be against the outer race d. be made only after heating the bearing - โ โ a The lubricant for an anti-friction bearing: Select one: a. will separate the moving parts completely b. must be cooled c. could be a grease d. prevents axial trust - โ โ c The most common and cheapest greases are not suitable for: Select one:
a. temperatures above 70ยฐC b. sealing dirt from bearings c. applications where they must stay in place d. applications where the components are infrequently lubricated - โ โ a Oil grooves in a sleeve bearing distribute oil: Select one: a. along the length of the shaft b. around the bearingสผs full circumference c. using the boundary lubrication principle d. in the high pressure zone of the bearing - โ โ a Regarding a shell bearing, what is the main purpose of the oil?: Select one: a. to cool the bearing b. to separate the bearing and the shaft c. to prevent corrosion d. to take up the shock of sudden loads - โ โ b The property of an oil which indicates its ability to support a load is: Select one: a. viscosity b. viscosity index c. pour point d. floc point - โ โ a
