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

Question 13

What is offset?

Answer 13

The parallel misalignment between two shafts and occurs at the coupling between the generator and turbine shafts

Question 14

What is shaft dogleg?

Answer 14

The angular misalignment of the turbine and generator shafts

Question 15

How many plumb wires are used for alignment?

Answer 15

4 wires are hung 90 degrees apart

Question 16

What is the first preliminary check?

Answer 16

With a dial indicator check the rise of each leg when loosing the mounting bolts

Question 17

What is one of the most important things to be checked before any readings are taken?

Answer 17

Whether the shaft is free or not

Question 18

How can you check the concentricity of the stationary components?

Answer 18

Temporarily install the upper and lower bridges and the head cover and take a measurement with a plumb wire and an electric micrometer

Question 19

When the unit is assembled the concentricity of the stationary components can be checked by?

Answer 19

Taking clearance readings

Question 20

Correcting the dogleg in the shafts requires?

Answer 20

Installing a shim pack between the coupling faces

Question 21

The second method used for aligning hydro units with adjustable shoe thrust bearings is using the adjustable feature of the shoes only to achieve equal?

Answer 21

Loading

Question 22

Move shaft to center in turbine bearing housing and move ______ to make it a plumb.

Answer 22

The top of the shaft

Question 23

The final step in the alignment process is the installation and adjustment of the…

Answer 23

Guide bearings

Question 24

To make the generator guide bearings concentric to the turbine guide bearings the _______ is used as a reference.

Answer 24

Shaft

Question 25

During turbine bearing installation several dowels are used to prevent _________

Answer 25

Lateral movement of the bearing