The Siemens 3RV1901-1AA00-0FJ0 is an auxiliary switch designed for lateral mounting on SIRIUS 3RV circuit-breakers in frame sizes S00 through S3. It provides one normally-open and one normally-closed contact pair, giving a feedback signal for the breaker's tripped or ON state.
Mounts laterally onto the left side of the 3RV breaker body — no additional DIN-rail space consumed beyond the breaker's own footprint. The 1 NO + 1 NC contacts are mechanically linked to the breaker's switching mechanism, so the auxiliary state follows the main contacts without relying on the breaker's internal trip bar.