10.
Corrective action
10.1.
Faults during operation/commissioning
Table 18:
Faults during operation/commissioning
Remedy
Description/cause
Fault
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 over-
run (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.
In spite of correct setting of limit
switching, actuator operated into the
valve end position.
●
Connect link across RWG to XK (terminals
23/24)
●
Connect external load to XK, e.g. remote indic-
ation.
●
Observe maximum load R
B
.
Current loop across RWG is open.
(Position feedback 0/4 – 20 mA is only possible if
the current loop is closed across the RWG.)
No value can be measured at meas-
uring points of the RWG.
Exchange reduction gearing.
Reduction gearing is not suitable for turns/stroke
of the actuator.
Measuring range 0/4 – 20 mA or
maximum value 20 mA at position
transmitter cannot be set or supplies
an incorrect value.
Call service.
The LED on the EWG either flashes in setting mode
a) single flash or b) triple flash:
a) EWG is not calibrated.
b) Magnet positions of EWG are not aligned.
The measuring range 0/4 – 20 mA at
EWG position transmitter cannot be
set.
Check setting, if required, reset end positions.
Refer to <Check switches> and replace the
switches if required.
Switch is defective or switch setting is incorrect.
Limit and/or torque switches do not
trip.
Dismount handwheel. Replace overload protection
and remount handwheel.
Actuator in version with overload protection for
manual operation: Shear pin rupture due to excess-
ive torque at handwheel.
Handwheel rotates on the shaft
without transmitting torque.
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.
45
SA 07.2 – SA 16.2 / SAR 07.2 – SAR 16.2
SEM 01.1/SEM 02.1
Corrective action
