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3710 and 3720 Positioners
W6062/IL
Figure 25. Cam Removed; Range Spring Free
From Summing Beam
Removing the Positioner
WARNING
Refer to the WARNING at the
beginning of the Maintenance section
of this manual.
1. If you are planning to remove a Type 3720
positioner, be sure to turn off electric power to the
Type 3722 converter. Disconnect field wiring.
Release all pressure to the positioner. Disconnect
the supply, instrument, and output tubing.
2. Unscrew the four captive cover screws (key 8)
and remove the positioner cover assembly (key 7).
3. Unscrew the three socket head screws (key 46)
and remove the positioner.
4. Inspect the feedback tie bar (key 42) attached to
the actuator hub. If necessary, unscrew the machine
screws (key 47) and remove the tie bar.
30
Removing the Feedback Arm Assembly
WARNING
Refer to the WARNING at the
beginning of the Maintenance section
of this manual.
1. Unscrew the cam locknut (key 37) and remove
the cam (key 36).
The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.
2. Loosen the zero adjustment locknut and turn the
zero adjustment knob (key 35) until the range spring
is free from the summing beam. See figure 25. Move
the feedback arm (key 21) until the range spring falls
away from the summing beam.
The feedback pivot cannot be removed
from the positioner base plate.
3. Remove the retaining ring (E-clip) (key 27) which
holds the feedback arm (key 21) onto the feedback
pivot. Remove the washer under the retaining ring
and pull the feedback arm from the pivot.
4. Remove the flanged bearing (key 22) from the
feedback pivot or from the feedback arm. Inspect
and replace the bearing, if necessary.
Instruction Manual
Form 5300
July 2005
Note
Note
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