Flowserve AF-17 Electronic Positioner - Manual (Page 19)

WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 19
4.7.5 Check Fuse F1
For AC boards, check fuse F1 to see if it is blown. If it is, replace with spare fuse F2 attached to PC Board and order another
fuse for spare (Newark part number 94F2146). IMPORTANT: To check fuse - remove it from circuit and test with ohmmeter.
Resistance should be about 6 ohms.
NOTE: If fuse F1 is blown, excessive voltage (possibly 120 VAC) was applied to the signal input circuit. If so, correct
this condition before changing fuse. See Paragraph A of Part 1.1.
For DC boards, check fuse F1 to see if it is blown. If it is, replace it with a 1 !?4 ", 250 volt, 3 amp fuse, available through
any electrical supplier. See Part 2.2 in DCAF17 IOM supplement.
4.7.6 Check basic actuator for proper operation using the proper AC voltage
A. Remove red and black leads coming from circuit board at terminals 3 and 4 (if already installed). Tape stripped ends of
these wires.
B. Alternately energize, with the appropriate AC voltage, terminals 1 and 3 and 1 and 4. The actuator should move clockwise
when energizing terminals 1 and 4, stopping only at the clockwise limit switch. The actuator should move counter-
clockwise when energizing terminals 1 and 3, stopping only at the counter-clockwise limit switch.
NOTE: For AF-17 240 VAC Positioner only, limit switches do not directly control motor. Therefore, the actuator will
not stop when the limit switches trip. Use care not to drive the actuator past its normal limits. Run the actuator to its
limits in each direction, to assure proper operation of the actuator.
4.7.7 Check for Noise Problems
If the circuit board’s light emitting diodes (LEDs) blink or seem to continuously glow, electrical noise is interfering with the
positioner’s input process signal. (Always use shielded cable for the process signal coming to the AF-17 board. Ground the
shield at only one end.) Adjust AF-17 positioner as necessary. See Section 4.0.
4.7.8 Replace Circuit Board
If problems still occur after taking these remedial steps, replace circuit board in the actuator.
5.0 OPERATIONAL VARIABLES
5.1 Sensitivity
The Worcester AF-17 Electronic Positioner has been designed to a standard sensitivity equivalent to approximately 240 positions
for a 15 second 90 degree shaft movement.
5.2 Reduced Travel Operation
A small amount of travel reduction can be achieved (4-6 degrees). This can be accomplished by applying maximum and minimum
input signals and adjusting the “Range” and “Zero” controls to determine the new rotation end limits. (Limit switch cams should
also be reset. See parts 4.1 and 4.4.)
5.3 Split Range
With AF-17 Positioner circuit board revisions (Revision R10 and later) split range adjustment capability is available with standard
board and may be obtained using the standard calibration procedures.
5.4 Reverse Action
The usual mode of operation of an actuator is to use an increasing signal for the open direction of travel and a decreasing signal
for the close direction of travel. For use in certain types of applications, it may be desirable to operate using a decreasing signal
for the open direction and an increasing signal for the close direction. For some valves this can be done by cross-line mounting
the actuator (mounting the actuator to the valve such that it is rotated 90° from the normal mounting position. This has the effect
of rotating the valve ball 90° with the actuator at its 4 mA position. As the signal is increased toward 20 mA the valve ball will
travel toward its closed position but in a counter-clockwise direction. Therefore, this method will work only with valves with round
seats, not with characterized seats). No positioner wiring changes would be required using this method. If cross-line mounting is
not feasible, the reversal can be accomplished at the positioner as follows:
Flow Control Division
Worcester Controls