10.
Corrective action
10.1
Faults during commissioning
Table 5:
Faults during commissioning
Remedy
Possible causes
Fault description
Exchange reduction gearing.
Reduction gearing is not suitable for
turns/stroke of the actuator.
Mechanical position indicator
cannot be set.
Determine overrun: Overrun = travel covered
from switching off until complete standstill.
Set limit switching again considering the
overrun (turn handwheel back by the amount
of the overrun).
The overrun was not considered when setting
the limit switching.
The overrun is generated by the inertia of
both the actuator and the valve and the delay
time of the controls.
Fault in end position
Actuator runs to end stop alt-
hough the limit switches work
properly.
Connect terminals 23/24 to XK across RWG.
Connect external load to XK, e.g. remote indi-
cation.
Consider maximum load R
B
.
Current loop via RWG is open.
(Position feedback 0/4 – 20 mA only functions
if the current loop is closed across the RWG.)
Position transmitter RWG
No value can be measured at
measuring points.
Exchange reduction gearing.
Reduction gearing is not suitable for
turns/stroke of the actuator.
Position transmitter RWG
Measurement range 4 – 20 mA
or maximum value 20 mA cannot
be set.
Check setting, if required, reset end positions.
→
Check switches and replace them, if requi-
red.
Switch is defective or switch setting is incor-
rect.
Limit and/or torque switches do
not trip.
Switch check
The red test buttons [1] and [2] are used for manual operation of the switches:
1.
Turn test button [1] in direction of the TSC arrow: Torque switch CLOSED trips.
2.
Turn test button [2] in direction of the TSO arrow: Torque switch OPEN trips.
If the actuator is equipped with a DUO limit switching (option), the intermediate
position switches (LSA and LSB) will be operated at the same time as the torque
switches.
1.
Turn test button [1] in direction of the LSC arrow: Limit switch CLOSED trips.
2.
Turn test button [2] in direction of the LSO arrow: Limit switch OPEN trips.
10.2
Motor protection (thermal monitoring)
In order to protect against overheating and impermissibly high temperatures at the
actuator, PTC thermistors or thermoswitches are embedded in the motor winding.
They trip as soon as the max. permissible winding temperature has been reached.
Behaviour during failure
If the signals are correctly wired within the controls, the actuator is stopped and can
only resume its operation once the motor has cooled down.
Possible causes
Overload, running time exceeded, max. number of starts exceeded, ambient
temperature is too high.
Remedy
Check cause, eliminate if possible.
33
SA 25.1 – SA 48.1/SAR 25.1 – SAR 30.1
Corrective action