Flowserve 75 Series Actuator - Manual (Page 3)

3
Worcester Series 75 Actuator Potentiometer Kit FCD WCAIM2067-00 - 09/04
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III. Adjusting Potentiometer
A. 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 lubicant that may be on the shaft before sliding
on the face gear.
a CAUTION: Do not overstretch the snap ring. Use the minimum
opening to allow it to slip over the gear.
B. Adjust the potentiometer spur gear (8) until there is approximately
1 ⁄
16
" engagement with the large face gear. Tighten the spur gear set
screw (9). If necessary, slightly bend potentiometer bracket to get
proper engagement.
C. Rotate the face gear back and forth to ensure smooth and easy
operation of the potentiometer.
D. For 90° Valves
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 (terminal 11) and the green lead (terminal 10) or the white/
black lead (terminal 11) and the purple lead (terminal 12), respec-
tively, as measured by ohmmeter, is between 80 and 90 ohms.
(Refer to instruction sheets listed in section I for potentiometer lead
locations and adjustments with other options.)
NOTE: It is not necessary to loosen or remove face gear snap ring
to rotate gear.
E. Power the actuator to the opposite position from where resistance
was measured.
F. 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.
NOTE: If unsuccessful in getting proper resistance readings,
potentiometer is defective and should be replaced.
The feedback potentiometer is now adjusted for use in the
75 actuator.
Attach the potentiometer caution label to the outside of the actuator
cover.
IMPORTANT: The feedback potentiometer is calibrated for only one
90° quadrant of valve operation. If the output shaft is repositioned
to another 90° quadrant or if the output shaft is rotated a multiple
of 360° from its original position, the feedback potentiometer will
no longer be in calibration and must be recalibrated.