Table of Contents

IV. Rotork Procedures

Disassembly Precautions................................................................................................... IV-1

Disassembly Preparations ................................................................................................. IV-2
Disassembly Procedure ..................................................................................................... IV-3
Cleaning and Inspection .................................................................................................... IV-7
Reassembly ....................................................................................................................... IV-7

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Intentionally Left Blank

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Rotork Procedures

Refer to Figures 13-1, 13-2, 13-3, 13-4, 13-5, 13-7 and 13-8

NOTE: Refer to provided training aid (i.e. actuator) for any component not identified in noted
drawings. Reference to Figure 13-6 may be helpful if student is working on a Category 1
actuator.

Disassembly Precautions

1. Do NOT work on energized equipment.

2. Do NOT attempt to lift heavy equipment or components by hand.

Figure 13-7 Rotork Add-on-Pak

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Disassembly Preparations

NOTE: This procedure does not include removal of the actuator from the valve.

1. De-energize the actuator control circuit and motor supply.

2. Establish a clean work area for placement of components.

3. Assemble the tools required to perform disassembly. (Tools required for the
disassembly of Rotork actuators in this course will be provided by the instructors.)

Figure 13-8 Syncropak Electrical Schematic

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Disassembly Procedure

1. Remove the three cap screws holding the switch mechanism cover to the gearcase.

2. Remove the switch mechanism cover by pulling it slowly and directly outward away
from the casing.

3. Inspect the switch mechanism cover "O" ring for damage or deformity; it will be reused
if in good condition.

4. Remove the switch mechanism using the following steps: (Refer to Figure 13-9)

NOTE: Do NOT disconnect the wiring on the microswitch blocks.

a. Remove the microswitch blocks from the switch mechanism mounting by pulling
the blocks toward the front plate against spring tension, then pivoting the
microswitch assemblies out of their mounting.

Figure 13-9 Switch Mechanism (Nuclear)

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NOTE: The microswitch assemblies on nuclear rated switch mechanism are removed by
loosening the hex nuts on the switch side of the front plate and pulling the switchblocks forward
until they can be pivoted away from their mountings.

b. Remove the light from its mounting by loosening the hex nut enough to allow
removal of the fixture.

c. Remove the two socket head cap screws on the baseplate of the switch mechanism.

d. SLOWLY pull the switch mechanism straight out, away from the housing, while
preventing interference with the light and microswitch assemblies.

5. Remove the torque shaft from the actuator housing. Do not disturb the torque shaft
length adjustment. (Refer to Figure 13-10)

Figure 13-10 Torque Shaft

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 6. Remove the drive bush by performing the following steps:

NOTE: During these steps, use caution when resituating the actuator casing to prevent injury to
personnel and damage to electrical components.

a. Reorient the actuator so that the drive bush on the actuator output is accessible.

b. Manually operate the actuator until the drive bush retainer set screw is visible
through the hole in the actuator base.

c. Loosen the set screw and unscrew the drive bush retainer by rotating
counter-clockwise.

NOTE: It may be necessary to use a punch to unseat the retainer from the drive bush.

d. Remove the drive bush by pulling outward to disengage it from the center column
lugs.

7. Handwheel removal:

a. Remove the socket head cap screw located near the base of the handwheel.

b. Grip the nylon retainer using needle-nose pliers.

c. Rotate the handwheel clockwise while pulling on the nylon retainer.

d. After the retainer is removed, pull upward on the handwheel assembly to remove it
from the casing.

8. Motor assembly removal:

a. Using the hand/auto lever, place the actuator in hand operation.

NOTE: Performing this step will remove the force exerted on the wormwheel by the clutch
spring via the clutch ring and clutch keys.

b. While supporting the motor, unscrew the cap screws holding the motor to the
gearcase.

c. Pull the motor assembly slowly and squarely from the gearcase, taking care not to
damage the gearcase oil seals with the threaded portion of the motor wormshaft.

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 d. Support the motor assembly at the casing. Do NOT allow tension to be exerted on
the motor leads. Disconnect the motor and thermostat leads.

NOTE: These disconnects for the motor and thermostat leads have been added locally to make
disassembly easier for training.

9. The Belleville spring pack is located at the base of the motor. The Belleville spring
pack assembly is oriented at the factory based on the desired actuator output torque and
thrust. Consult a course instructor for additional information.

10. Center column removal:

a. Ensure that the hand/auto finger is lying lengthwise on the wormwheel. If not, push
the lower end of the hand/auto finger sideways with a screwdriver.

b. While capturing the clutch spring and washer, remove the "O" ring and then the
clutch spring and washer from the center column.

c. Remove the clutch ring and clutch keys by grasping the keys with needle-nose
pliers. Do not drop the clutch keys into the gearcase.

NOTE: For size 70/90 actuators, grasp the clutch ring or cap screws with the needle-nose pliers.

d. Lift out the yoke assembly.

e. Remove the cap screws holding the thrust pad. Remove the thrust pad and
wormwheel.

f. Remove the cap screws holding the thrust base to the actuator. Remove the thrust
base.

NOTE: The size 70/90 actuators have a two-piece thrust base.

g. Tap the top of the center column to drive it out through the bottom of the casing.

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Cleaning and Inspection

1. Clean the actuator's mechanical assemblies/components using a degreaser or solvent

compatible with the oil rings and seals.

2. Inspect the wormwheel for damaged or worn teeth. Also inspect the wormwheel drive
pins.

NOTE: If the motor assembly is to be replaced, a new wormwheel should be used.

3. Inspect the limit switch wheel and worm for wear. If necessary, gears should be
replaced as sets.

4. Inspect the clutch keys and keyways for nicks, burrs, etc.

5. Inspect the helix action to ensure correct torque shaft operation. The helix action
should be smooth without binding.

6. Inspect the hand/auto assembly components for damage.

7. Inspect the drive bush for nicks, burrs, or excessive wear. A drive bush showing
excessive signs of wear should be replaced.

8. Inspect the lower, threaded portion of the center column for damaged threads caused by
the drive bush retainer set screw. Dress the threads if necessary.

9. Inspect all oil seals and "O" rings for damage; replace as necessary.

10. Disassemble the thrust base and inspect bearing surfaces.

Reassembly

1. Install the center column up through the bottom of the gear case. Install the thrust base
on the actuator casing.

2. Install the wormwheel and thrust pad through the top of the casing. Check for free
rotation of the wormwheel.

3. Mount the motor assembly and connect the motor and thermostat leads. Carefully
engage the wormshaft and wormwheel. Avoid damaging the gearcase oil seals.

4. Install and position yoke. Ensure that the yoke set screw is correctly located in the
thrust pad hole.

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 5. Slide the clutch ring and clutch keys down the center column. Rotate the center
column, if necessary, to prevent the keys from engaging the drive pins on the
wormwheel or the lugs on the yoke.

6. Ensure that the keys are flat on the wormwheel. Install the clutch spring and washer.
Carefully press the spring into compression and roll the "O" ring into the groove.
Slowly release pressure on the clutch spring until it is held by the "O" ring.

7. With the hand/auto finger still flat on the wormwheel, ensure that the yoke is correctly
positioned, with the top of the lugs on either side of the yoke approximately 0.015 inch
from engagement under the clutch ring collar. The set screw is adjusted to raise or
lower the yoke. Tighten the locknut on the set screw after adjustment.

8. Install the torque shaft in the gearcase.

9. Install the switch mechanism in the actuator. Extreme caution must be used in locating
the switch mechanism wiring to prevent crushing the leads under the mechanism
baseplate. Install and tighten the switch mechanism cap screws.

NOTE: The pointer on the switch mechanism faceplate should be aligned with the arrow on the
switch mechanism frame. If it is not, stop and consult with the course instructor(s) before
proceeding.

10. Mount the microswitches in the switch mechanism frame. Install the lamp and bracket
on the switch mechanism. To set the switch mechanism, refer to the electrical controls
section of this chapter. Install the switch mechanism cover temporarily to protect it
from damage by slowly installing the cover with the mechanism centered. This ensures
proper engagement of the position indicator.

11. Install the handwheel assembly on the casing by centering the handwheel oil seal on the
center column and pushing the handwheel housing toward the gearcase. Be sure the oil
seal is properly positioned.

12. Install the nylon retainer in the gearcase while rotating the handwheel
counter-clockwise. Install the retainer cap screw.

13. Install the drive bush:

a. Reorient the actuator casing so that the center column base is accessible.

b. Install the drive bush; ensure full drive lug engagement.

c. Install and tighten the drive bush retainer.

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NOTE: For the purposes of this training course, the drive bush retainer is not set screwed in
place.

14. Perform an operational test in accordance with the operational testing section of this
chapter.

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