Figure 8-18: Supply Interruption In The Bypassed State - Siemens sirius System Manual

3RW3 semiconductor motor control unit
Supply interruption in
bypassed state
8-34
If the load voltage is switched off in the bypassed state while the auxiliary
supply continues to be applied at terminals A1/A2, the soft starter performs
a direct start of the motor after the load voltage is switched on again. To pre-
vent this, the "on" command must be removed in the event of the loss of the
main voltage.
The following graphic illustrates what happens when the supply is inter-
rupted in the bypassed state:
L1-L2-L3
A1-A2
IN
Bypass
T1-T2-T3
U
N
U
S
Control supply
Startup completed
voltage on
Bypass closes
Main voltage
on
Start command

Figure 8-18: Supply interruption in the bypassed state

Direct start
To avoid a direct start after the return of
Failure of the
the main voltage, the ON command must
main voltage
be removed in the event of the failure
failure of the main voltage (T
Main voltage
returns
>= xx ms)
off
SIRIUS System Manual
GWA 4NEB 430 0999-02b