Messages and diagnosis
6.2 3RW30: Troubleshooting
SIRIUS 3RW30 / 3RW40
58 Manual, 10/2018, NEB535199502000/RS-AB/005
6.2 3RW30: Troubleshooting
Fault Cause Remedy
Impermissible electronics
supply voltage
The control supply voltage does not corre-
spond to the soft starter's rated voltage.
Check the control supply voltage; an incorrect
control supply voltage could be caused by a
power failure or a voltage dip.
Bypass overload A current > 3.5 x I
e
of the soft starter oc-
curs for > 60 ms in bypass mode (e.g.
because the motor is blocked).
Check the motor and load, and check the soft
starter's dimensions.
Missing load voltage, phase
failure / missing load
Cause 1: Phase L1 / L2 / L3 is missing at
the start of soft starting or fails / collapses
when the motor is operating.
A trip occurs if a phase failure is detected
by the 3RW30 at the start of soft starting:
• at the beginning of starting: tripping
time t > 0.5 s
• in run-up or in bypass mode: phase
failure not detected
Connect L1 / L2 / L3 or correct the voltage
dip.
Note:
As soon as the motor is in run-up or bypass
mode, these faults are no loner detected. The
soft starter does not go to a fault state in
these cases, and contact 13-14 remains
closed.
If the phase failure occurs in the uncontrolled
phase, the response varies depending on
whether the control voltage has a reference or
connection to the AC network, or whether it is
isolated:
• If the control voltage is isolated, the phase
failure of the uncontrolled phase will also
be detected when the motor is switched
off. With an On command, the 3RW30
goes immediately to a fault state, and con-
tact 13 / 14 does not close.
• If the control voltage has a reference to
the AC network, the phase failure of the
uncontrolled phase is not detected, and
with an On command, the soft starter at-
tempts to start the motor. This can cause
the motor to hum.
Cause 2: a motor that is not powerful
enough is connected.
A trip occurs if the current flowing through
the 3RW30 soft starter at the start of soft
starting is less than 10% of the rated op-
erational current of the 3RW30, or less
than 1 A.
Connect a motor with a higher rated opera-
tional current, or select a different soft starter.
Note:
As soon as the motor is in run-up or bypass
mode, these faults are no loner detected. The
soft starter does not go to a fault state in
these cases, and contact 13-14 remains
closed.
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 Technical
Assistance (Page 15).
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