USBR FIST VOL. 2-1

Question 1

The rotating weight of the unit is transferred through the?

Answer 1

Thrust bearing, upper bridge, and stator frame to the foundation

Question 2

Where is the thrust bearing located in an umbrella unit?

Answer 2

Below the rotor

Question 3

There are typically three types of thrust bearings used in hydroelectric units, they are the?

Answer 3

Adjustable shoe, spring loaded bearing, and the self equalizing

Question 4

The adjustable shoe thrust bearing uses a _____ under each of the shoes for adjusting the height and loading of the shoes

Answer 4

Jack screw

Question 5

How does one install the thrust block?

Answer 5

It is heated to a predetermined temperature and lowered over the shaft, with the units on the jacks. The block is set on the thrust shoes, the rigging removed, and radial keys and keeper installed

Question 6

With the block still hot the jacks are released to allow the…

Answer 6

Full weight of the unit to set the block in place against the keys

Question 7

With the system on, it is possible for a couple of people to rotate a unit by hand or move the rotating components laterally on the thrust bearing. What are both required during the alignment process?

Answer 7

Both rotation and lateral movement

Question 8

As alignment deviates, loading on the _______ will increase and so will vibration levels.

Answer 8

Guide bearings

Question 9

Any increase in vibration from misalignment will decrease the?

Answer 9

Factor of safety for operation in severe circumstances

Question 10

The concentricity of the stationary components can be checked by?

Answer 10

A single tight wire can be used as a plumb reference

Question 11

No reading point deviates more than _______ inch from a straight line connecting the top and bottom reading point for shaft straightness.

Answer 11

.003

Question 12

Plumb of center of shaft runout is…

Answer 12

.000025 multiplied by the length of the shaft from the highest plumb reading to the lowest plumb reading