Regardless of whether or not the PMG simulator is available, the) full rate wicket
gate timing must be set before the unit is watered up. As mentioned previously, the
wicket gate time should be obtained from a hydraulic transient study or test reports.
Once all the items on the checklist, other than operational tests and adjustments, are
completed and just prior to starting the unit for the first time following the overhaul,
a final inspection of the unit should be made. Some of the items listed below will
have been checked previously, but because of potential damage to the machine, they
should be checked again. This inspection should include, but not be limited to, the
Visual inspection of generator housing and spiral case.
A very thorough
inspection of the generator housing and spiral case should be made to check for any
bolts, nuts, tools, etc. In the generator housing, check on top of rotor arms, under
fan covers, or any place that a part or tool could possibly have been left. Once these
areas have been inspected and verified to be clean, no one should be allowed back
in. If it is necessary for someone to go back into these areas, they should remove
everything from their pockets and make a list of every tool that is taken in so that
they can verify nothing is left inside when they are finished.
Bearing lubricant levels.
All bearing lubricant levels should be checked just prior
to startup. If the lubricant level is indicated by a sight glass, the valve to the sight
glass should be checked to make sure it is open and the level in the sight glass is
Cooling water supplies.
The flow and pressure of the cooling water to the generator
and bearing coolers should be checked to make sure it is adequate. The packing box
cooling water supply should also be checked.
Clearances between stationary and rotating parts should be checked.
Bearing covers, vapor guards, rotor fan blades, etc., should be checked for adequate
Bearing and PMG
insulation. 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. The insulation should be checked
with an ohmmeter prior to startup following the procedure in
FIST Volume 3-11,
"Generator Thrust Bearing Insulation and Oil Film Resistance."