Power engineer class 4-part B Exam Questions with Correct Answers | 100%
Verified solutions
Most important purposes of lubrication are: ÇÇFriction reduction, wear reduction and
corrosion reduction
The separation of contacting surfaces is achieved by: ÇÇLubrication
Friction can be described as : ÇÇa resistance to motion
lubrication principle purposes: ÇÇreduce friction
reduce wear
corrosion reduction
control the Temp
shock absorber
provide sealing
* major purpose reduce friction and wear.
Semi solid lubricants pr greases are made by combining a liquid lubricant usually:
ÇÇpetroleum oil with a thickening agent.
The fact that grease has a thick, stiff consistency means that it can be used under conditions
where oil could leak or drain away, leaving the bearing dry. Also grease is less likely to drip or
,splash from bearings. Therefore, it has a wide application in the: ÇÇTextile and food
industires
Grease is suitable for: ÇÇBall bearings and roller bearings
Grease is not suitable where large amounts of: ÇÇHeat must be continually carried away
from the bearing. under these conditions, a liquid lubricant would be used.
Specialty greases are mad of: ÇÇMineral oils thickened with soil lubricants such as graphite,
mica, and talc. They are used for heavily operated machinery that operate at slow speeds.
Liquid lubricants are divided into 3 general classes: ÇÇ1 mineral oils
2. fixed oils
3. synthetic oils
Mineral oils are produced from: ÇÇcrude petroleum
Mineral oils are the most: ÇÇcommonly used class of lubricants.
Cooling for oil lubricated, heavily loaded bearings can be: ÇÇA separate oil cooler
Lubricants act as a: ÇÇcushion to absorb shock( gear teeth)
,Mineral oils constitute the majority of all: ÇÇlubricants from crude petroleum
Greases are a : ÇÇMixture of mineral oil and thickening agents.
Viscosity is a measure of the resistance of a : ÇÇLiquid to internal deformation or shear. it
indicates the liquids ability to flow.
Viscosity indicates the: ÇÇ-ability of an oil to a support a load
- Power required to overcome internal friction
- amount of heat produced due to internal friction
Oil viscosity is greatly affected by: ÇÇIts temperature
as temperature increases in viscosity oil will become: ÇÇthinner and less viscous (viscosity
will be reduced)
as temperature decreases in oil viscosity will be ÇÇThicker and more viscous (viscosity will
be increased)
A commonly used method to measure viscosity of oil is: ÇÇSaybolt viscometer
, in a saybolt viscometer, the units are expressed in: ÇÇSaybolt Seconds Universal (SSU)
the viscosity index is a: ÇÇMeasuremnt of how much the viscosity of a certain oil changes
with a temperature change.
The pour point of oil is the: ÇÇLowest tempt which a certain oil will flow.
Oils used in cold climates must have a ÇÇLow pour point
The flash point of a oil is the ÇÇtemp at which it will give off sufficient vapour to ignite
the fire point of an oil is ÇÇthe temp at which it gives off enough vapour to burn
continuously
Some lubricating oil additives are: ÇÇ-anti oxidants
-detergent- dispersants
-viscostiy index improvers
-antifoam additives
-pour point depressants
- corrosion inhibitors
Lubrication can be generally divided into 2 categories: ÇÇ1. boundary lubrication
Verified solutions
Most important purposes of lubrication are: ÇÇFriction reduction, wear reduction and
corrosion reduction
The separation of contacting surfaces is achieved by: ÇÇLubrication
Friction can be described as : ÇÇa resistance to motion
lubrication principle purposes: ÇÇreduce friction
reduce wear
corrosion reduction
control the Temp
shock absorber
provide sealing
* major purpose reduce friction and wear.
Semi solid lubricants pr greases are made by combining a liquid lubricant usually:
ÇÇpetroleum oil with a thickening agent.
The fact that grease has a thick, stiff consistency means that it can be used under conditions
where oil could leak or drain away, leaving the bearing dry. Also grease is less likely to drip or
,splash from bearings. Therefore, it has a wide application in the: ÇÇTextile and food
industires
Grease is suitable for: ÇÇBall bearings and roller bearings
Grease is not suitable where large amounts of: ÇÇHeat must be continually carried away
from the bearing. under these conditions, a liquid lubricant would be used.
Specialty greases are mad of: ÇÇMineral oils thickened with soil lubricants such as graphite,
mica, and talc. They are used for heavily operated machinery that operate at slow speeds.
Liquid lubricants are divided into 3 general classes: ÇÇ1 mineral oils
2. fixed oils
3. synthetic oils
Mineral oils are produced from: ÇÇcrude petroleum
Mineral oils are the most: ÇÇcommonly used class of lubricants.
Cooling for oil lubricated, heavily loaded bearings can be: ÇÇA separate oil cooler
Lubricants act as a: ÇÇcushion to absorb shock( gear teeth)
,Mineral oils constitute the majority of all: ÇÇlubricants from crude petroleum
Greases are a : ÇÇMixture of mineral oil and thickening agents.
Viscosity is a measure of the resistance of a : ÇÇLiquid to internal deformation or shear. it
indicates the liquids ability to flow.
Viscosity indicates the: ÇÇ-ability of an oil to a support a load
- Power required to overcome internal friction
- amount of heat produced due to internal friction
Oil viscosity is greatly affected by: ÇÇIts temperature
as temperature increases in viscosity oil will become: ÇÇthinner and less viscous (viscosity
will be reduced)
as temperature decreases in oil viscosity will be ÇÇThicker and more viscous (viscosity will
be increased)
A commonly used method to measure viscosity of oil is: ÇÇSaybolt viscometer
, in a saybolt viscometer, the units are expressed in: ÇÇSaybolt Seconds Universal (SSU)
the viscosity index is a: ÇÇMeasuremnt of how much the viscosity of a certain oil changes
with a temperature change.
The pour point of oil is the: ÇÇLowest tempt which a certain oil will flow.
Oils used in cold climates must have a ÇÇLow pour point
The flash point of a oil is the ÇÇtemp at which it will give off sufficient vapour to ignite
the fire point of an oil is ÇÇthe temp at which it gives off enough vapour to burn
continuously
Some lubricating oil additives are: ÇÇ-anti oxidants
-detergent- dispersants
-viscostiy index improvers
-antifoam additives
-pour point depressants
- corrosion inhibitors
Lubrication can be generally divided into 2 categories: ÇÇ1. boundary lubrication
