User Manual

7
Worcester Actuation Systems Series 75 Electric Valve Actuator FCD WCAIM2013-01 - 08/04
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SPECIAL NOTE:
If during any of these checks, the actuator
shaft stops other than at the required positions, a readjust-
ment of the center-off cams is needed. At no time shall
both center-off switches be activated by their cams at the
same time. The N.O. contacts on both center-off switches
are typically closed. The center-off switch levers must be
tripped by their center-off cams at different times.
Therefore, the center-off cams should be set as close to the
90 degree position as possible, yet the cam/switch actua-
tion for each switch is never at the identical position.
If the center-off switches are set to actuate at a close
angular differential, the actuator shaft may oscillate, or not
operate. Loosen one cam and move this cam to increase
the actuation differential between each of the center-off
switches.
If the center-off switches are set to actuate at a wide
angular differential, the actuator will not stop at a true
center-off position. Adjust one or both cams to decrease
the angular differential between each of these switches.
g. As a fi nal check, alternately apply power to terminals 1 and
4, 1 and 3, and 1 and 7 for AC, (+ to the 1 and - to the 4;
- to 1 and + to 3; - to 8 and + to 7 for DC).
No oscillation or hunting of the actuator output shaft
should occur.
If the above problems are noted, simply readjust the
center-off cams as noted in Step f.
Switch confi guration is as above (when viewed from the
terminal strip side of the actuator.
Actuator shown at 0° position (fully CW).
10-23 Size 75 Actuators
Item Description
1
Circuit Board Sub-Assembly
2
Insulating Board
3
Bracket-Right (Long)
4
Grommet-Rubber
5
Mounting Screws (Cir. Board)
6
Washer-Nylon
7
Bracket-Left (Short)
8
Mounting Screws (Bracket)
9
Spacer (Bracket)
25-30 Size 75 Actuators
Item Description
1
Circuit Board Sub-Assembly
2
Insulating Board
3
Circuit Board Bracket
4
Mounting Screw (Bracket)
5
Grommet-rubber
6
Washer-Nylon
7
Mounting Screw (Cir. Board)
8
Capacitor (Round Or Rectangular)
9
Capacitor Tie (See Note)
10
Capacitor Bracket And Screw (See Note)
Note: Not Used For Round Type Capacitor With Threaded Lug.
120 VAC Shown