USBR FIST 2-7

Question 1

One of the best sources of information in planning a major overhaul should be the?

Answer 1

Maintenance records for the unit or units involved

Question 2

At least 6 months, but preferably a year before the planned overhaul a thorough inspection of the unit should be done to?

Answer 2

Determine the condition of the equipment

Question 3

A list of weights of all of the machines components should be made from the…

Answer 3

Drawing information

Question 4

If the unit inspection indicated that substantial welding repair it required , a ____________ for the required repairs should be written and distributed to all personnel that will be involved in the welding.

Answer 4

Welding procedure

Question 5

On units with replaceable seal rings, a ________ should be kept onsite

Answer 5

Spare set of rings

Question 6

What are your 4 pre shutdown readings?

Answer 6

Shaft runout readings
Bearing temperatures
Pressures
Permanent magnet generator voltage

Question 7

What are your 3 preteardown readings?

Answer 7

Guide bearing and seal ring clearances
Generator air gap
Shaft alignment readings

Question 8

Why should most parts be matched marked?

Answer 8

To make sure they are installed in exactly the same position from which they were removed

Question 9

Why should the rigging to lift the thrust block include turnbuckles?

Answer 9

So that the block can be kept level to prevent binding when it is lifted off the shaft

Question 10

Upon removal all guide and thrust bearings should be thoroughly inspected. Minor scratches and even some deep gouges can be repaired adequately by?

Answer 10

Carefully scraping the high spots from the Babbitt surface

Question 11

In most cases the repair of cavitation damage can be accomplished much more effectively with the runner…

Answer 11

Removed from the turbine pit

Question 12

Where an overlay of a dissimilar metal material is being used, such as bronze or stainless steel over mild steel, enough material should be removed to allow for at least _____ weld passes to be made.

Answer 12

3

Question 13

If the packing box is still structurally sound, the interior bore of the box can be built up with a properly applied ______ coating

Answer 13

Epoxy

Question 14

The bearing cooling coils should be thoroughly _________ and __________ tested.

Answer 14

Inspected, hydrostatically

Question 15

How do you find the units center?

Answer 15

The upper bridge and headcover should be installed after all the rotating parts have been removed. A single tight wire should be hung through the unit and reference measurements taken from the stator, the turbine bearing housing, the packing box bore and to trammel points in the draft tube

Question 16

The dowels have a very tight fit to prevent?

Answer 16

The components from shifting once the part is positioned

Question 17

When doweled components are moved during the alignment process following the overhaul what is necessary?

Answer 17

Redoweling

Question 18

A more accurate method of measuring the preload of a bolt is to measure the?

Answer 18

Amount the bolt stretches as the nut is tightened

Question 19

To make the bearing centers all concentric the shaft must be perfectly plumb. This can be accomplished by?

Answer 19

Installing the turbine bearing and shimming the shaft to center in the turbine bearing

Question 20

When taking readings with a feeler gauge it is essential that the segment be held…

Answer 20

Level and tight against the adjusting bolt

Question 21

What is squeeze

Answer 21

Squeeze is the amount the servomotors travel after the gates contact eachother

Question 22

There should be generous leakage upon initial startup after the installation of a new turbine shaft packing. The packing gland should be __________ evenly and in _______ steps until the leakage is reduced sufficiently.

Answer 22

Tightened, small

Question 23

A very thorough inspection of the generator housing and spiral case should be made to check for…

Answer 23

Any bolts, nuts, tools, etc.

Question 24

The upper guide bearing, the thrust bearing, and the PMG are usually insulated from the frame to prevent damage that could occur from…

Answer 24

Circulating currents passing through them. Insulation should be checked with a ohmmeter

Question 25

What are your operational readings?

Answer 25

Bearing heat run
Shaft runout readings
Load rejection tests