Siemens SIRIUS 3RW30 Manual page 64

Messages and diagnosis
6.5 3RW40: Troubleshooting
Fault
Motor protection tripping Overload
relay / thermistor:
Thermistor protection: wire break-
age / short-circuit (optional for
devices 3RW402. to 3RW404.):
Thermal overload on the device:
Missing load voltage, phase failure
/ missing load:
Device error
64
Cause
The thermal motor model has tripped.
After an overload trip, restarting is inhib-
ited until the recovery time has elapsed.
- Overload relay tripping time: 60 s
- Thermistor tripping time: When the
temperature sensor (thermistor) in the
motor has cooled down.
Temperature sensor at terminals
T11/T12/T22 is short-circuited or defec-
tive, a cable is not connected, or no sen-
sor is connected.
Overload trip of the thermal model for the
power unit of the 3RW40
Possible causes
Too many starts,
•
Motor starting time too long,
•
Ambient temperature in switching
•
device's environment too high,
Minimum installation clearances not
•
complied with.
Cause 1: Phase L1 / L2 / L3 is missing or
fails / collapses when the motor is operat-
ing.
A trip occurs if the current measured by
the current transformers of the 3RW40 is
less than 20% of the minimum rated
motor current that can be set on the
3RW40 potentiometer:
At starting/coasting down: tripping
•
time t > 1 s
In bypass mode: tripping time t > 5 s
•
Cause 2: a motor that is not powerful
enough is connected.
A trip occurs if the current measured by
the current transformers of the 3RW40 is
less than 20% of the minimum rated
motor current that can be set on the
3RW40 potentiometer, or less than 2 A.
Cause 3: Motor phase T1 / T2 / T3 is not
connected.
Soft starter defective.
Remedy
- Check whether the motor's rated opera-
tional current I is set correctly, or
e
- Change the CLASS setting, or
- Possibly reduce the switching frequen-
cy, or
- Deactivate the motor protection (CLASS
OFF), or
- Check the motor and the application
Check the temperature sensor and the
wiring
Wait until the device has cooled down
again, possibly increase the current limit-
ing value set for starting, or reduce the
switching frequency (too many consecu-
tive starts). If necessary, retrofit the op-
tional fan (for 3RW402. to 3RW404.)
Check the load and the motor, check
whether the ambient temperature in the
soft starter's environment is too high
(derating above 40 °C, refer to chapter
Technical data (Page 127)), comply with
the minimum clearances.
Connect L1 / L2 / L3 or correct the volt-
age dip.
Set the rated operational current for the
connected motor correctly on the 3RW40
potentiometer, or set it to the minimum.
Connect the motor properly (e.g. jumpers
in the motor terminal box, repair switch
closed etc.)
Contact your SIEMENS partner or Tech-
nical Assistance (Page 15).
SIRIUS 3RW30 / 3RW40
Manual, 10/2018, NEB535199502000/RS-AB/005