12.3 Check limit and torque seating
.
Move valve in direction OPEN and switch off by manually tripping limit
switch LSO (figure L-3).
Press switch operating lever just slightly!
Perform the same test in direction CLOSE with limit switch LSC.
.
Move valve in direction CLOSE and switch off by manually tripping torque
switch TSC (figure L-4).
Press switch operating lever just slightly!
.
Perform the same test in direction OPEN with torque switch TSO.
.
For
limit seating
in direction CLOSE:
Move valve in direction CLOSE and switch off by manually tripping limit
switch LSC.
If valve does not stop, check connections and controls’ wiring.
12.4 Determine overrun and check setting of the limit switching
Determine overrun of actuator in both directions by visual inspection
(amount of additional rotation of stem after actuator has been switched off):
.
Manually move valve in direction CLOSE (figure L-5),
while observing cam for limit switch LSC (figure L-4).
For
limit seating
in direction CLOSE:
When the switch has tripped (figure L-6), continue turning handwheel to
the final position and check whether the remaining travel corresponds to
the overrun. If this is not the case, the limit switching must first be set, as
described from page 15.
For
torque seating
in direction CLOSE:
Limit switch LSC must trip shortly before reaching end position CLOSED
(figure L-6). Thus, it can be recognised whether the seating is performed
in end position or during operation (torque failure).
For this setting, the overrun is ignored.
18
Multi-turn actuators SAI 6 – SAI 100 / SARI 6 – SARI 100
for valve automation Inside Containment in nuclear power plants
Operation instructions
Figure L-3: Checking the limit switch
LSO
Figure L-4: Checking the torque switch
TSC
