2ND 2

Question 1

A machine is a device for converting force to useful work. It can be used to:

a) change the size of a force
b) change the direction of a force
c) change the speed or rate a force is acting
d) all three of the above

Answer 1

d) all three of the above

Question 2

Of the below statements concerning machine efficiency, which one is not a true statement?

a) input is equal to useful output plus useless output
b) efficiency is equal to useful output divided by input
c) transformers are less efficient than reciprocating pumps
d) improper operation of the machine can seriously affect the efficiency

Answer 2

c) transformers are less efficient than reciprocating pumps

Question 3

A shaft or journal revolving in an oil lubricated bearing is usually identified with:

a) sliding friction
b) rolling friction
c) fluid friction
d) a combination of all three

Answer 3

c) fluid friction

Question 4

A bearing that supports or restricts the longitudinal motion of a rotating shaft is called a:

a) thrust bearing
b) radial bearing
c) journal bearing
d) guide bearing

Answer 4

a) thrust bearing

Question 5

All of the below factors have an effect on the formation of the desired oil wedge. Which one must operators give the most careful attention to prevent bearing damage?

a) bearing clearance
b) viscosity of the lubricant
c) shaft or journal speed
d) bearing load

Answer 5

c) shaft or journal speed

Question 6

Lubricating oil is normally fed into a horizontal journal bearing from the:

a) top
b) bottom
c) side
d) both side and bottom

Answer 6

a) top

Question 7

Journal and thrust bearings are more susceptible to damage during:

a) start-ups
b) shut-downs
c) both start-up and shut-down operations
d) full operating speeds

Answer 7

c) both start-up and shut-down operations

Question 8

While bearing clearances will vary somewhat because of different design and loading characteristics, it is generally established that for each inch of shaft diameter the clearance should be about:

a) 0.001”
b) 0.002”
c) 0.003”
d) 0.004”

Answer 8

a) 0.001”

Question 9

All of the below statements relating to bearing load are true except:

a) bearing load is generally thought of as the magnitude of force interacting between the shaft and the supporting bearing
b) bearing loads may be as high as several hundred pounds per square inch
c) high bearing loads tend to squeeze the oil film out of the pressure area of the bearing
d) heavily loaded bearings generally require an oil low in viscosity

Answer 9

d) heavily loaded bearings generally require an oil low in viscosity

Question 10

All of the below statements concerning oil grooves in bearings are true except:

a) the oil groove is generally located in the high pressure area of the bearing
b) oil grooves have two functions – to deliver the proper quantity of oil over the bearing surface and to prevent excessive loss of oil from the bearing
c) oil grooves are usually chamfered on the edges to prevent a “wiping action” effect
d) oil grooves should stop at least ½ inch from each of the bearing to minimize leakage

Answer 10

a) the oil groove is generally located in the high pressure area of the bearing

Question 11

An increase in bearing temperature may indicate:

a) a change in surrounding air temperature
b) insufficient oil
c) dirty oil
d) a combination of all three of the above

Answer 11

d) a combination of all three of the above

Question 12

Antifriction or roller bearings are made to carry:

a) radial loads
b) thrust loads
c) angular loads
d) any of the above or a combination of all three

Answer 12

d) any of the above or a combination of all three

Question 13

Ball bearing life may be shortened by:

a) over or under lubrication
b) improper installation
c) entrance of abrasive material into moving parts
d) any or all of the above

Answer 13

d) any or all of the above

Question 14

If the oil reservoir in a ring oiled bearing is carried too high the ring:

a) may stop and cause bearing failure
b) actions may become erratic and cause bearing temperatures to rise
c) will turn more slowly due to increased friction in turning through the oil
d) any or all of the above

Answer 14

c) will turn more slowly due to increased friction in turning through the oil

Question 15

The desired oil wedge is formed in a Kingsbury thrust bearing by:

a) a pumping action
b) the pivoted shoe or blocks
c) pressurized lubrication
d) decreasing the viscosity of the oil

Answer 15

b) the pivoted shoe or blocks

Question 16

The below statements concerning a Kingsbury spherical thrust bearing are all true except:

a) it combines the functions of a lower generator guide and thrust bearing
b) it is self-aligning
c) the concave shoes are mounted on pivots to form the desired oil wedge
d) the thrust load ratings are similar to those of a conventional Kingsbury bearing of the same diameter

Answer 16

a) it combines the functions of a lower generator guide and thrust bearing

Question 17

Which of the following statements concerning vertical turbine guide bearings is true:

a) the bearing may be oil lubricated and lined with lignum-vitae
b) the bearing may be water lubricated and lined with babbit
c) the oil lubricated bearing is contained in a tub of oil
d) the lignum-vitae strips are inserted in the bearing shell

Answer 17

d) the lignum-vitae strips are inserted in the bearing shell

Question 18

Which of the below features is not normally found on a horizontal turbine thrust bearing installation:

a) bearing contained in an oil reservoir or tub
b) water cooling coils
c) provisions for pressurized lubrication
d) oil seal rings

Answer 18

c) provisions for pressurized lubrication

Question 19

Which of the below features is not normally found on a horizontal turbine journal bearing installation:

a) provisions for pressurized lubrication
b) bearing contained in an oil reservoir or tub
c) oil rings
d) self-aligning provisions

Answer 19

b) bearing contained in an oil reservoir or tub

Question 20

Which of the below features is not normally found on a Gibbs horizontal turbine shaft thrust and journal bearing:

a) pressurized lubrication
b) water cooling coils
c) oil rings for the journal bearings
d) pivoted blocks or shoes

Answer 20

d) pivoted blocks or shoes