USBR FIST 2-7 Flashcards
One of the best sources of information in planning a major overhaul should be the?
Maintenance records for the unit or units involved
At least 6 months, but preferably a year before the planned overhaul a thorough inspection of the unit should be done to?
Determine the condition of the equipment
A list of weights of all of the machines components should be made from the…
Drawing information
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.
Welding procedure
On units with replaceable seal rings, a ________ should be kept onsite
Spare set of rings
What are your 4 pre shutdown readings?
Shaft runout readings
Bearing temperatures
Pressures
Permanent magnet generator voltage
What are your 3 preteardown readings?
Guide bearing and seal ring clearances
Generator air gap
Shaft alignment readings
Why should most parts be matched marked?
To make sure they are installed in exactly the same position from which they were removed
Why should the rigging to lift the thrust block include turnbuckles?
So that the block can be kept level to prevent binding when it is lifted off the shaft
Upon removal all guide and thrust bearings should be thoroughly inspected. Minor scratches and even some deep gouges can be repaired adequately by?
Carefully scraping the high spots from the Babbitt surface
In most cases the repair of cavitation damage can be accomplished much more effectively with the runner…
Removed from the turbine pit
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.
3
If the packing box is still structurally sound, the interior bore of the box can be built up with a properly applied ______ coating
Epoxy
The bearing cooling coils should be thoroughly _________ and __________ tested.
Inspected, hydrostatically
How do you find the units center?
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
The dowels have a very tight fit to prevent?
The components from shifting once the part is positioned
When doweled components are moved during the alignment process following the overhaul what is necessary?
Redoweling
A more accurate method of measuring the preload of a bolt is to measure the?
Amount the bolt stretches as the nut is tightened
To make the bearing centers all concentric the shaft must be perfectly plumb. This can be accomplished by?
Installing the turbine bearing and shimming the shaft to center in the turbine bearing
When taking readings with a feeler gauge it is essential that the segment be held…
Level and tight against the adjusting bolt
What is squeeze
Squeeze is the amount the servomotors travel after the gates contact eachother
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.
Tightened, small
A very thorough inspection of the generator housing and spiral case should be made to check for…
Any bolts, nuts, tools, etc.
The upper guide bearing, the thrust bearing, and the PMG are usually insulated from the frame to prevent damage that could occur from…
Circulating currents passing through them. Insulation should be checked with a ohmmeter
What are your operational readings?
Bearing heat run
Shaft runout readings
Load rejection tests
