Siemens SIRIUS 3RW40 - Page 64

Messages and diagnosis
6.5 3RW40: Troubleshooting
SIRIUS 3RW30 / 3RW40
64 Manual, 10/2018, NEB535199502000/RS-AB/005
Fault
Cause
Remedy
Motor protection tripping Overload
relay / thermistor:
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.
- Check whether the motor's rated opera-
tional current I
e
is set correctly, or
- 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
Thermistor protection: wire break-
age / short-circuit (optional for
devices 3RW402. to 3RW404.):
Temperature sensor at terminals
T11/T12/T22 is short-circuited or defec-
tive, a cable is not connected, or no sen-
sor is connected.
Check the temperature sensor and the
wiring
Thermal overload on the device: 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.
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.
Missing load voltage, phase failure
/ missing load:
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
Connect L1 / L2 / L3 or correct the volt-
age dip.
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.
Set the rated operational current for the
connected motor correctly on the 3RW40
potentiometer, or set it to the minimum.
Cause 3: Motor phase T1 / T2 / T3 is not
connected.
Connect the motor properly (e.g. jumpers
in the motor terminal box, repair switch
closed etc.)
Device error Soft starter defective. Contact your SIEMENS partner or Tech-
nical Assistance (Page 15).