GE MS6001B, Maintenance Instructions Manual

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Inspection and Maintenance — GEK 107048 Hot Gas Path Inspection — Inspection Procedures
HGP-I-22
Inspection Form PGS/GT-FF-6105) is known. Then see if the gaps are within the minimum speci-
fied allowance for the worst diaphragm tooth condition.
Operation 6 — How to Make First Stage Nozzle Ellipticity Checks
Note: Ellipticity is the condition of deviation from a circular form. Measure-
ment of the first stage nozzle is to determine the amount of deviation,
or the, “Out of Roundness,” of the nozzle assembly when it is measured
out of the unit. Ellipticity can be measured on the first stage nozzle since
the segments are held in place by a retaining ring and are removed as
an assembled unit in both the upper and lower halves. The second and
third stage nozzle segments are assembled to the turbine casing and el-
lipticity checks are not required.
Assistance from your General Electric Company Field Service Repre-
sentative in obtaining ellipticity readings is recommended.
1. Set the upper and lower halves of the first stage nozzle on a reasonably level surface and take ellip-
ticity readings as called for on Inspection Form PGS/GT-FF-6097.