Replacing The Short Pivot Assembly; Replacing The Process Drive Flexure - Emerson Fisher KC Series Instruction Manual

4195KA, KB, KC, and KS Controllers
1
END BUSHING
ADJUSTMENT ARM
1
END BUSHING
NOTE:
BEFORE TIGHTENING THE DRIVE FLEXURE MOUNTING SCREWS,
1
POSITION THE SHAFT SO THE END BUSHINGS "FLOAT" IN THE BEARINGS.
26A9784-E
A5682 / IL
Figure 6-20. Cutaway of Long Pivot Clevis Assembly
6. Loosen the screw on the pivot adjustment arm of
the replacement pivot clevis assembly, and adjust
the arm to the same length as the arm on the pivot
assembly being replaced.
7. Attach the replacement pivot clevis assembly to
the mounting plate with the two mounting screws
(key 102).
8. Loosely connect the drive flexure to the pivot
adjustment arm on the new pivot clevis assembly.
See figure 6-20. The adjustment arm of the long
pivot clevis assembly is connected to a shaft that
turns on bushings at each end of the shaft. In the
next step, position the shaft so that both bushings
''float'' inside the bearings and do not rest against
the end of either bearing.
9. Apply 75 percent of the capsular element range
to the capsule. The drive flexure should be straight
and horizontal. Before tightening the drive flexure
cap screws (key 12), hold the pivot shaft in the
middle of the bushing end play. Be sure neither
bushing is resting against the inside end of either
bearing. Tighten the drive flexure cap screws to hold
the pivot shaft in position. Adjust the length of the
pivot adjustment arm as needed until the drive
flexure is horizontal. Take care not to kink or twist
the flexure when tightening the screws.
6-28
10. Connect the left-hand end of link 5 (key 88) to
the pivot adjustment arm in the hole position noted
in step 3.
BEARING
11. Replace the tie bar (key 97).
12. Perform the capsular element maintenance
calibration procedure in this section. Perform the
controller calibration procedures and, if necessary,
perform the appropriate remote set point calibration
procedure in Section 3, 4, or 5.

Replacing the Short Pivot Assembly

1. Remove process pressure from the controller.
SHAFT
2. Note the hole positions of links 1 and 5 (keys 88
and 90) and disconnect the links from the short pivot
clevis assembly (key 89). Also, note the screw
position of the linearity adjustment for later
reference.
BEARING
3. Remove the two machine screws (key 102)
attaching the short pivot clevis assembly (key 89) to
the mounting plate (key 77) and remove the pivot
clevis assembly.
4. Set the linearity adjustment screw in the
replacement pivot assembly to approximately the
same location as noted in step 2.
5. Position the replacement short pivot clevis
assembly on the mounting plate, and attach it with
the two machine screws.
6. Attach links 1 and 5 (keys 88 and 90) in the same
hole position as noted in step 2.
7. Perform the capsular element maintenance
calibration procedures in this section. Perform the
controller calibration procedures and, if necessary,
the appropriate remote set point calibration
procedure in Section 3, 4, or 5.

Replacing the Process Drive Flexure

1. Set the process pressure to 75 percent of the
capsular element range.
2. Remove the tie bar (key 97) from the capsular
element assembly by removing the mounting screws
(key 103).
3. Using an Allen wrench, remove the cap screws
and washers (keys 12 and 13) to disconnect the
drive flexure (key 79) from the drive bracket
assembly (key 84) and from the pivot adjustment
arm of the long pivot clevis assembly (key 78).
Remove the drive flexure.
4. Loosely connect the replacement drive flexure,
making sure it is straight and horizontal.
Instruction Manual
Form 5207
April 2007