Woodward TG-10E, Installation And Operation Manual

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TG-10E/-13E/-17E Actuator Manual 04045
18 Woodward
Figure 4-2. Wiring Diagram for Actuator Calibration Circuit
7. With no current applied, make sure that there is no travel of the terminal
shaft from the minimum position.
8. A recalibration is required if any of the following conditions exists:
(1) With 20 mA current applied, if less than 1-degree movement or more
than 3-degree movement is seen from minimum position
(2) With 160 mA current applied, if less than 37-degree movement or more
than 39-degree movement is seen from minimum position (27 to 29
degrees for TG-10E)
(3) If the terminal shaft does not rotate smoothly from one position to
another, or if it does not take the same position for the same
potentiometer setting when rotated from the increase or decrease
position
9. SHUT DOWN THE TURBINE following the turbine manufacturer’s
instructions, remove the actuator cover and supply tube for actuator cover. (If
the actuator is mounted horizontally, first drain the actuator oil through the oil
drain plug.)
10. If condition (1) or (2) in Step 8 above exists, skip Step 11 below and go to
Step 12 to recalibrate the actuator.
11. If condition (3) in Step 8 above exists, the transducer assembly must be
disassembled before recalibrating the actuator to make sure that there is no
binding of the feedback lever, spring, transducer assembly, or pilot-valve
plunger.
Disassemble the transducer assembly as follows:
(1) Remove the two screws holding the transducer clamp bracket (brass
bracket). Do NOT change the settings of the level adjusting screw or
the range adjustment slider (see Figure 4-1 for identification of parts).
(2) Turn the clamp bracket slightly to one side to release the restoring
lever from the terminal lever.
(3) Remove the restoring spring.
(4) Lift off the transducer assembly and carefully move it to the side.
(5) Pull out the pilot-valve plunger and its bushing.
(6) Remove the snap ring from the pilot-valve bushing and pull out the
pilot-valve.
(7) Immerse the pilot-valve plunger and bushing in diesel fuel oil or
approved cleaning solvent and wash ultrasonically or by agitation. Use
a non-metallic brush or jet of compressed air to clean slots, bushing
filter screen, holes, and pilot-valve plunger orifice.