Siemens SIRIUS 3RT2 Manual page 23

Note
Fitting of auxiliary switches
When the 3RA2816-0EW20 function module for star-delta (wye-delta) start is used, the
following applies:
No more than one 3RH29 lateral auxiliary switch block (product version E03 and higher) may
be mounted onto the line contactor (Q11) and onto the star (wye) contactor (Q12).
SIRIUS 3RA28 function modules for mounting on 3RT2 contactors
Manual, 02/2019, A5E03656507620A/RS-AD/005
Product description
3.3 Applications
23