Flowserve AF-17 Electronic Positioner - Manual (Page 9)

WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 9
3.2.4 Adjusting Potentiometer
A. Reference paragraph 4.7.6 for moving the actuator shaft electrically.
B. 10-30 75 Actuator:
Place the large face gear (12) over the actuator shaft with the gear teeth down and secure with snap ring (16).
NOTE: The face gear utilizes a friction fit to the shaft. For best results, wipe off any lubricant that may be on the shaft
before sliding on the face gear.
CAUTION: Do not overstretch the snap ring — use the minimum opening to allow them to slip over the gear.
C. Adjust the potentiometer spur gear until there is approximately 1 /
16
" engagement with the large face gear. Ensure there is
minimum backlash between the gears. Tighten the spur gear set screw.
D. Rotate the face gear back and forth to ensure smooth and easy operation of the potentiometer.
E. IMPORTANT: For 90° Valves:
Depending on whether the AF-17 board is installed and wired, either measure the resistance directly at the potentiometer
wires if not installed or at the AF-17 terminal block (TB-1) if installed and wired. With the actuator either in the OPEN (full
CCW) or CLOSED (full CW) position, and power off, rotate the face gear, thus turning the potentiometer shaft, until the
resistance between the white/black lead (AF-17 terminal 2) and the green lead (AF-17 terminal 3) or the white/black lead
(AF-17 terminal 2) and the purple lead (AF-17 terminal 1) respectively, as measured by ohmmeter, is between 80 ohms
and 90 ohms.
NOTE: It is not necessary to loosen or remove face gear snap ring(s) to rotate gear.
F. Power the actuator to the opposite position from where resistance was measured. Reference paragraph 4.7.6 for moving
actuator shaft electrically.
G. At this position, with power off, measure the resistance at the same terminals as stated above. The resistance reading
should be greater than 700 ohms. If not, then power actuator back to original position and adjust potentiometer again, if
necessary, as stated in paragraph E above. If unsuccessful in getting proper resistance readings, potentiometer is
defective and should be replaced.
H. The feedback potentiometer is now adjusted for use in the 75 actuator. Add the potentiometer caution label to the outside
of the actuator cover.
CAUTION: If the actuator shaft is manually rotated a multiple of 360° from its original position, the feedback
potentiometer will no longer be in calibration. It must be recalibrated per paragraphs E-G above, in order for the
AF-17 board to operate properly.
3.2.5 Important Note
The feedback potentiometer is calibrated for only one 90-degree quadrant of valve operation.
If the valve and actuator output shaft is repositioned to another 90-degree quadrant the feedback potentiometer must be
recalibrated as per Section 3.2.4.
The Series 75 actuators offer a manual override feature. Whenever repositioning the valve using the manual override
capability on these actuators, move the valve only within the 90 degrees for which the feedback potentiometer has
been calibrated.
TB-2
Terminal Wire Color
1 Green
2 White/Black
3 Purple
(DO NOT CUT POTENTIOMETER WIRES!)
Flow Control Division
Worcester Controls