A.3.3
3RW55 soft starter in standard (inline) circuit and stopping function DC
braking with 2 braking contactors
WARNING
Automatic restart.
Can cause death or serious injury.
If a starting command is pending, a restart will be triggered automatically after the reset. This
particularly applies if the motor protection has tripped. Dangerous states of the system can
result.
Reset the start command (e.g. via the PLC or switch) before performing a reset.
To do this, for example, link the group error output (terminals 95 and 96) into the control.
Use the "DC braking with external braking contactor" function if applications with larger mass
inertias (centrifugal masses) have to be stopped (J
load
≤ 5 x J
motor
).
If you select the stopping function "DC braking with external braking contactor", you additionally
require 2 braking contactors. Set the output 1 to "DC braking contactor". If you select the
stopping function "Dynamic DC braking without contactor", you do not require a braking
contactor.
You will find further information in chapter DC braking with external braking contactors
(Page 154)
Requirements
• 3RW55 soft starter
• Parameterization required
• The 3RW55 soft starter used meets the requirements of the following table:
Size
Article number of the
3RW55 soft starter
Number of required ex‐
ternal braking contac‐
tors up to 400 V
Number of required ex‐
ternal braking contac‐
tors higher than 400 V
Size 1
3RW551.-.....
1 or 2
2
Size 2
3RW5521-.....
3RW5524-.....
3RW5525-.....
3RW5526-.....
3RW5527-.....
2
Size 3
3RW553.-.....
Size 4
3RW554.-.....
Size 5
3RW555.-.....
Example circuits
A.3 Special applications
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006
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