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4.7
ROTOR INSPECTION
a. Assemble the balance and inspection arbor (Par. 3.6) and place the
rotor in the inspection stand (Par. 3.6) per Figure 4,4.
b.
Measure and record on Figure 4.4 the full indicator reading
(FIR) of:
1. Rotating air seal O.D. (Figure 4.4, Dimension A).
2. Tip turbine shroud (forward side) O.D. (Figure 4.4, Dimension B).
c. Measure and record (on Figure 4.4) the maximum running radius of:
(Mark high spots with Dykem).
1. Rotating air seal O.D. (Figure 4.4, Dimension C).
2. Tip turbine shroud (forward side) O.D. (Figure 4.4, Dimension D).
4.8
ROTOR BALANCING
List the rotor blades in a column in order of decreasing moment weights.
Divide the list into pairs and determine the difference in moment weights of
the blades in each pair; ie., 1 and 2, 3 and 4, 35 and 36.
List these
differences in an adjoining column.
Lay out the blades on a balance plot
O
(Figure 4.0) by placing the blades of a pair opposite each other beginring
with blades 1 and 2 in blade positions 1 and 19; and alternately selecting
pairs of blades from the top and bottom of the list; ie., blades 36 and 35
in blade positings 2 and 20.
The blade plot should be filled out in this
manner.
Differences in blade moment weights should be determined for
opposite carriage position.
A judicious relocation of blades may have to
be made to minimize these differences.
Any relocation of blades should be
made by pairs.
Instrumented blades should be placed at least 900 apart.
Carriers and seals should be listed as described above for the blades.
The balance plot for the carriers should be made as described for the
blades.
Differences in blade moment weights for opposite carrier positions
should be placed on the plot and a judicious relocation of carriers should
be made so that pairs of carriers with a large difference in moment weights
are placed so as to balance blades with a large differ-ence in moment weights.
This procedure should also be followed for the seals.
11-4.5
R-2
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