Allis Chaimers Flashcards
Although machines may be extremely large, _________________ must be maintained in fit and alignment of various parts.
Close tolerances
Suspended type machines have the thrust bearing and an upper guide bearing located where?
Above the rotor
Larger low speed machines use what to secure the poles to the rim?
Driven tapered keys
Why is a hollow shaft required in an adjustable blade pump or propeller type turbine?
So that oil pipes can be carried through the shaft from the oil head at the top and of the unit to the turbine servomotor
The designated oil level is usually about one-third the length of the bearing above its lower end for what system?
Guide bearing lubrication
Brakes are usually operated by compressed air at ___________ psi. Brakes may also be used as jacks. When jacking they are operated by oil pressure of ________ to _______ psi.
75-100 psi
1000-3500 psi
High pressure bearing lubrication is frequently used to…
Reduce the breakaway torque
The high pressure system has a pressure switch that prevents starting of the machine until the high-pressure pump assembly is up to pressure, approximately ________ psi.
1000 psi
Prior to erection of the unit, the turbine or pump runner and shaft are centered and supported in a position at a specific distance, usually _________ below the correct operating position.
1/4 to 3/4 inch
Provide fins on the plumb bob and allow it to hang in a Pail of heavy oil to damp any swings. Protect the plumb line from all _________.
Strong air currents
Electric welding on any part of the machine is a serious hazard to bearings. A bearing surface can be _____________ if welding current passes across it.
Damaged rapidly
If possibly all electric welding especially on the rotating element should be done when?
Before the bearings are assembled
How should you test the cooling coil for water tightness?
With the oil reservoir empty and the water pressure raised 50% above normal if possible
A bearing can easily be damaged by a particle of lint or dirt. Consequently, precautions must be taken during assembly of the bearing to avoid…
The presence of dust and dirt
Segmental bearings made up of independently adjustable segments must be set to?
Proper elevation and clearance
Bearings and other parts such as instrument elements, Kaplan features, conduit piping etc. which make contact directly or indirectly, with the shaft above the rotor are usually…
Insulated
Check this insulation with a 500 volt insulation resistance meter and if the resistance is less than 20,000 ohms ….
Inspect the insulation and make the necessary corrections.
Before drawing the couplings together their mating surfaces must be in alignment, parallel, clean and free from burrs. The couplings must be drawn up evenly to…
Prevent distortion
The bolt tension can be determined by an accurate measurement of the?
Elongation
Use steel music wire plumb lines with heavy finned weights , immersed in pails of oil to prevent?
Wires from swaying and twisting
Check commutator runout with a?
Dial indicator rather than by visual observations
Various instruments and relays and its associated wiring must be carefully installed making sure that it does not…
Short-circuit the bearing insulation
The rotating parts of the machine must be in dynamic balance. This may require the addition of?
Balance weights to the rotor
Before connecting the generator to the power system check?
Phase sequence of the generator
If an operation check of the shaft runout is required make it as described in the appendix after the generator…
Is operating under full load
