Functions   
5.1 Start modes 
  SIRIUS 3RW30 / 3RW40 
36  Manual, 10/2018, NEB535199502000/RS-AB/005 
The SIRIUS 3RW40 soft starter has intrinsic device protection, current limiting, and ramp-up 
detection functions. These functions do not form part of the SIRIUS 3RW30 soft starter. 
 
When using the 3RW30: Make sure the selected ramp time is longer than the actual motor 
ramp-up time. If not, the SIRIUS 3RW30 may be damaged because the internal bypass 
contacts close when the set ramp time elapses. If the motor has not finished starting up, an 
AC3 current that could damage the bypass contact system will flow. 
When using the 3RW40: The 3RW40 has an integrated ramp-up detection function that 
prevents this operating state from occurring.  
The maximum ramp time for the SIRIUS 3RW30 soft starter is 20 seconds An appropriately 
dimensioned SIRIUS 3RW40 or 3RW44 soft starter should be chosen for startup processes 
with a motor ramp-up time > 20 seconds.  
 
Figure 5-1  Principle of the voltage ramp