AMOT 10GEF, Operation And Maintenance Manual, Page: 39 / 80

39
Electric Actuator
OMMG00012 Rev 12 – NOV 2019
4.8.3 Limit Switch Replacement
CAUTION
During replacement of the limit switches, the actuator must be
manually positioned. If the actuator is mounted on a valve which is
installed in the pipework, it will affect the process flow of the system.
Replace the limit switches as follows (refer to Fig 13, page 40)
WARNING
Lethal voltages are exposed when the actuator cover is removed,
presenting an electric shock hazard to personnel. Electrical power
supplies must be isolated from the actuator before the cover is
removed.
1 Remove the socket head cap screws and carefully lift off the cover.
2 Unscrew the motor strap (16), pull apart and remove to clear the upper
limit switch cam (11).
3 Unscrew the screw in the centre of the position indicator (1) and remove
the indicator from the position indicator shaft (17).
4 Remove the cable ties securing the potentiometer wiring to the
potentiometer bracket (3) and potentiometer bracket mounting pillar
(18).
5 Remove the screw (30) and split washer (29) and pull off the
potentiometer bracket (3) from the position indicator shaft.
6 Undo the grubscrew (8) and pull off the large spur gear (7) from the
position indicator shaft.
7 Turn the manual drive handle as necessary to access the grubscrews (10
and 23) in both the upper and lower limit switch cams (11 and 13).
8 Undo the grubscrews to loosen both upper and lower limit switch cams on
the shaft.
CAUTION
When the two screws (22) securing the lower limit switch bracket
(21) are unscrewed, they can damage the lower limit switch cam (13).
The screws (22) must be undone evenly and in small increments
whilst raising the limit switch assembly and cams to prevent the
screws applying pressure to the underside of the cam.
9 Turn the cams to access the lower limit switch bracket screws (21). Undo
the screws evenly and in small increments whilst raising the limit switch
assembly and cams together to prevent the screws damaging the lower
cam.
10 Remove the two screws (21) and slide the limit switch assembly, both
cams and cam spacer (12) from the shaft.