Siemens SIRIUS 3RU - Auxiliary Contact Response

Operation
9.5 Response of the auxiliary contacts
SIRIUS 3RU thermal overload relays / SIRIUS 3RB electronic overload relays
Manual, 09/2016, A5E03656507420A/RS-AB/003
121
Test function in the case of 3RB20 / 3RB21 and 3RB30 / 3RB31 electronic overload relays
Correct functioning of the relay when ready for operation can only be checked by pressing
the TEST button with the motor current flowing (device/electronics test). Current sensing, the
motor model, and the tripping unit are tested.
You will find details of the procedure for conducting the test and the necessary prerequisites
in Chapter "Safety instructions for use in hazardous areas (3RB2 and 3RB3) (Page 69)".
9.5
Response of the auxiliary contacts
Auxiliary contacts
The overload relay is equipped with an NO contact (NO 97-98) for the "tripped" signal and an
NC contact (NC 95-96) for disconnecting the contactor. The auxiliary contacts have high
contact reliability; this makes them suitable for PLCs. Furthermore, the high switching
capacity facilitates direct switching of the contactor coil.
The table below shows how the auxiliary contacts respond when the TEST, STOP (3RU21
only), and RESET buttons are pressed.
READY
TEST
STOP
RESET
NC 95/96
NO 97/98
Switch position
indicator 3RB2 /
3RB3
--
Switch position
indicator 3RU21