Lubrication Flashcards Preview

Millwright 2nd Year > Lubrication > Flashcards

Flashcards in Lubrication Deck (48)
Loading flashcards...
0
Q

What are some negative effects of friction

A

Causes wear
generates waste heat
is resistant to movement increasing power consumption

1
Q

Friction resistance movement what is the lubricants main job

A

To reduce resistance

2
Q

Positive effects of friction

A

Provides traction between rolling elements
promotes accurate tracking in bearing raceways
provides a means of starting stopping and acceleration

3
Q

Three types of friction

A

Sliding
rolling
fluid

4
Q

What is sliding friction

A

Produce when one surface slides across another

5
Q

What is rolling friction

A

Movement of one surface rolling over another

6
Q

What is fluid friction

A

Resistance to flow within the fluid

7
Q

How does a lubricant reduce friction

A

Separates the moving surfaces with a film that has less friction that a moving surface

8
Q

What are four functions of a lubricant

A

Protect against corrosion
carry away heat
carry away contaminants
help seal

9
Q

What is a full film lubrication

A

Think enough to completely separate the surfaces within a continuous film

10
Q

What is the last elasto-hydrodynamic film lubrication

A

Completely separates two surfaces and is therefore a type of fulfillment lubrication

11
Q

How is a boundary film formed

A

Low speeds
Viscosity is too low to support the load
Not enough lube

12
Q

How is an oil wedge created

A

Uses the rotation of the shaft to form an oil wedge that forces a full film of fluid into the loaded area

13
Q

What is viscosity

A

Measurement of fluid friction

Fluids that have low viscosity, flow easy

14
Q

Does viscosity effect film strength

A

Yes

15
Q

Three factors that affect viscosity

A

Temperature
pressure
speed

16
Q

What is pour point

A

Lowest temperature at which an oil is observed to flow

17
Q

What are centistokes

A

Unit of viscosity that has been excepted by industry worldwide

18
Q

Viscosity index is a number that

A

Identifies the amount of change in the viscosity of a lubricant over a temperature range

19
Q

What is it called when a vapor above an oil will ignite when a flame is passed over it

A

Flash point

20
Q

How is a low temperature engine grade indicated

A

With a “W”

21
Q

Oils without a “W” are for what season

A

Summer

22
Q

What is the purpose of a multigrade engine oil

A

To accommodate the start up in conditions that are both hot and cold

23
Q

Where are naptha based oil’s mainly used

A

North America

24
Q

Between Paraffin and naptha what has a very high wax content

A

Paraffin

25
Q

What based oil’s do not wear out

A

Petroleum based

26
Q

What are problems are synthetic oils developed to solve

A

To solve lubricating problems.

27
Q

Is there wax in synthetic oil’s

A

No

28
Q

What are additives

A

Chemicals that are added to the base oil to enhance the performance of the oil under specific operating conditions

29
Q

What percentage do additives make up of oil

A

22%

30
Q

What do you rust and corrosion inhibitors avoid

A

Costly maintenance and repair fees

31
Q

Two types of corrosion

A

Rusting and acid attack

32
Q

Extreme pressure additive protect against what

A

Welding of surface asperities when metal to metal contact occurs.

33
Q

Common types of solid additives

A

Graphite
molybdenum
Teflon

34
Q

How far up the lowest rolling element in an oil bath should the oil be

A

1/3 to 1/2 way up the lowest rolling element

35
Q

What does a bottle oiler rely on to lubricate

A

Vibrations

36
Q

What does a wick feed oiler rely on

A

Capillary action or attraction

37
Q

Drop feed oiler relies on what to lubricate

A

Gravity

38
Q

How does a ring or chain oiler work

A

Hangs from the shaft and dips into an oil bath and transfers oil onto the shaft to flow into the bearing

39
Q

How does a pressure lubrication system work

A

A pump delivers the oil onto the shaft which flows on to the bearings

40
Q

Two types of air activated lubrication systems

A

Oil mist and the air oil system

41
Q

What applications is a blocked lubricator used for

A

Large stationary engines and reciprocating compressors

42
Q

What is it called when oil is circulated through The machines bearings and back through the filters on the lubrication console to remove any contaminants that are in the system

A

Oil line flushing

43
Q

Greece is a liquid lubricant mixed with what

A

Thickener

44
Q

List three properties of a multipurpose grease

A

Wide temperature range
water resistant
Mechanically stable in high speed bearings

45
Q

Is a lower number of grease going to be thicker or thinner

A

Thinner

46
Q

What are the two methods of applying grease

A

Single point and centralized

47
Q

Single point Greece message don’t need any what?

A

Pumps
Metering
Valves