Module - Lubrication - Part B Flashcards Preview

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Flashcards in Module - Lubrication - Part B Deck (32):
1

Proper level of lubricant in a rolling element bearing is
a) halfway up the second from bottom rolling element.
b) halfway up the top rolling element.
c) halfway up the lowest rolling element.
d) halfway up the complete bearing (to the centreline of the shaft).

c) halfway up the lowest rolling element.

2

Movement of oil in a wick feed oiler is by
a) pump.
b) centrifugal force.
c) gravity.
d) capillary action.

d) capillary action.

3

A measure of grease stiffness is referred to as
a) cone test.
b) drop point.
c) consistency .
d) viscosity.

c) consistency

4

Thickeners for greases can be made from compounds that are classified chemically as
a) emulsifiers.
b) squeegees.
c) soaps.
d) solid solubles.

c) soaps.

5

The system which offers advantages where there are a large number of lubrication points is the
a) drop feed lubricator system.
b) wick feed lubricator system.
c) ladder lubricator system.
d) centralized lubrication system.

d) centralized lubrication system.

6

What is the formula for Surface Speed?

(RPM x π x Dia) / 12 = Feet per minute

7

Why is it important not to allow the oil level in an oil bath lubrication system to go above the centreline of the lowest rolling element?

To avoid churning, which would produce extra heat.

8

What are two disadvantages of a bottle lubricator?

1. Oil is not recirculated, but wasted.
2. It is restricted to uses where surface speeds are low.

9

Should a constant level lubricator be mounted on the left or the right side of the housing if the rotation is clockwise?

Left side.

10

What are two important functions of a sight glass on a lubrication system?

To monitor the oil level and the condition of the oil.

11

Is it best to take an oil sample immediately after a machine has been running at its normal operating temperature or after it has cooled down?

Immediately after running, to establish a wear rate for the machine.

12

What is a grease?

Grease is a liquid lubricant mixed with a thickener.

13

How does a grease thickener work?

The thickener acts like a sponge to hold the lubricant and also controls the flow of the grease to the area to be lubricated.

14

What is drop point referring to in a grease?

This is the lowest temperature at which the lubricant will begin to drip from a grease.

15

What is one of the oldest grease thickeners used?

Soap

16

Why should you not use grease with different thickeners?

Mixing results in a softer grease with a lower usable operating temperature.

17

What does grease consistency depend on?

Consistency depends on type of thickener, quantity of thickener, and temperature

18

What is the purpose of having EP additives in a grease?

To prevent damage from welding at the tips of the asperities on the loaded surfaces.

19

What is an advantage of a single point grease application system?

Simple (no pumps, metering valves etc.), compact (no grease lines) and inexpensive.

20

What is a disadvantage of a singe point grease application system?

When there is a large number of lubrication points, in which case more time is required to monitor the process.

21

What types of grease cups are considered automatic?

Spring-loaded, and electric timer style.

22

What is necessary before injecting grease into a grease nipple?

Clean the grease fitting thoroughly before attaching the grease gun.

23

Give two advantages of centralized lube systems.

It eliminates the risk of contamination from dirt on a grease gun nozzle or dirt getting into a grease cup when you refill it, and metering valves ensure that the correct quantity of lubricant is applied.

24

How full should the housing be for a grease-lubed bearing?

Housings should not be more than 1/3 full.

25

What are the three types of solid lubricants often used in industry?

The more common types used in the millwright trade are graphite, PTFE (Teflon) and molybdenum disulphide

26

What colour is graphite type solid lubricant?

Grey-black.

27

Which solid lubricant has the greater load-carrying capacity, graphite or Teflon?

Graphite.

28

Which lubricant may be used where oil and grease are not adequate?

Solid lubricants.

29

Which is the best one to use to carry away heat (oil, grease, solid lubricants)?

Oil.

30

Which is the best one to use to flush away contaminants (oil, grease, solid lubricants)?

Oil.

31

Which is the best one to use if you need it bonded to a surface permanently (oil, grease, solid lubricants)?

Solid lubricants.

32

What is the recommended level of oil in a bearing?

No higher than halfway up the lowest rolling element.