System overview   
1.7 Components and combinations 
  SIRIUS Innovations 
66  System Manual, 01/2011, A8E56203870002-03 
1.7.5.1  SIRIUS 3RA28 function modules for mounting on SIRIUS 3RT2 contactors 
3RA28 function modules for mounting on 3RT2 contactors 
SIRIUS 3RA28 function modules for mounting on SIRIUS 3RT2 contactors enable the 
control circuit wiring to be reduced significantly. With star-delta (wye-delta) starters, for 
example, they replace the control circuit wiring in its entirety. 
Table 1- 18  3RA28 function modules for mounting on 3RT2 contactors 
Area  Customer benefits 
Functions 
  Direct-on-line, reversing, and star-delta (wye-delta) start 
  Time-delayed switching of contactors (0.05 to 100 s) 
  ON-delay and OFF-delay versions 
  Star-delta (wye-delta) function module without extra control circuit wiring 
  Switch position indication for the contactor via a mechanical plunger 
Dimensioning and 
design 
  Only one version for S00 and S0 
  Suitable for control voltages of 24 to 240 V AC/DC 
  Contactor coil controlled via semiconductor output 
  Star-delta (wye-delta) switchover 0.5 to 60 s 
  Star-delta (wye-delta) changeover delay: 50 ms 
Mounting 
advantages 
  Easy plug-on assembly of a starter, without tools 
  Removable terminals 
  Screw-type and spring-loaded terminals 
Application 
areas/customer 
benefits 
  Assembly of star-delta (wye-delta) starters, including timing function and 
electrical interlock, without additional wiring 
  Universal applicability thanks to wide voltage and time ranges