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Millwright 2nd Year > Lubrication > Flashcards

Flashcards in Lubrication Deck (48):
0

Friction resistance movement what is the lubricants main job

To reduce resistance

1

What are some negative effects of friction

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

2

Positive effects of friction

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

3

Three types of friction

Sliding
rolling
fluid

4

What is sliding friction

Produce when one surface slides across another

5

What is rolling friction

Movement of one surface rolling over another

6

What is fluid friction

Resistance to flow within the fluid

7

How does a lubricant reduce friction

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

8

What are four functions of a lubricant

Protect against corrosion
carry away heat
carry away contaminants
help seal

9

What is a full film lubrication

Think enough to completely separate the surfaces within a continuous film

10

What is the last elasto-hydrodynamic film lubrication

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

11

How is a boundary film formed

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

12

How is an oil wedge created

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

13

What is viscosity

Measurement of fluid friction
Fluids that have low viscosity, flow easy

14

Does viscosity effect film strength

Yes

15

Three factors that affect viscosity

Temperature
pressure
speed

16

What is pour point

Lowest temperature at which an oil is observed to flow

17

What are centistokes

Unit of viscosity that has been excepted by industry worldwide

18

Viscosity index is a number that

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

19

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

Flash point

20

How is a low temperature engine grade indicated

With a "W"

21

Oils without a "W" are for what season

Summer

22

What is the purpose of a multigrade engine oil

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

23

Where are naptha based oil's mainly used

North America

24

Between Paraffin and naptha what has a very high wax content

Paraffin

25

What based oil's do not wear out

Petroleum based

26

What are problems are synthetic oils developed to solve

To solve lubricating problems.

27

Is there wax in synthetic oil's

No

28

What are additives

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

29

What percentage do additives make up of oil

22%

30

What do you rust and corrosion inhibitors avoid

Costly maintenance and repair fees

31

Two types of corrosion

Rusting and acid attack

32

Extreme pressure additive protect against what

Welding of surface asperities when metal to metal contact occurs.

33

Common types of solid additives

Graphite
molybdenum
Teflon

34

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

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

35

What does a bottle oiler rely on to lubricate

Vibrations

36

What does a wick feed oiler rely on

Capillary action or attraction

37

Drop feed oiler relies on what to lubricate

Gravity

38

How does a ring or chain oiler work

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

39

How does a pressure lubrication system work

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

40

Two types of air activated lubrication systems

Oil mist and the air oil system

41

What applications is a blocked lubricator used for

Large stationary engines and reciprocating compressors

42

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

Oil line flushing

43

Greece is a liquid lubricant mixed with what

Thickener

44

List three properties of a multipurpose grease

Wide temperature range
water resistant
Mechanically stable in high speed bearings

45

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

Thinner

46

What are the two methods of applying grease

Single point and centralized

47

Single point Greece message don't need any what?

Pumps
Metering
Valves