Auxiliary switch for SIRIUS contactor line
The Siemens 3RH2911-1XA22-0MA0 is a SIRIUS auxiliary switch designed for snap-on mounting onto the front of contactor relays and power contactors in sizes S00, S0, S2, and S3. It provides 2 NO instantaneous contacts (no leading or lagging switching) and carries a contact reliability rating of 1 faulty switching per 100 million operations at 17 V, 1 mA — a figure that matters for PLC-level signal integrity in low-energy circuits.
Current ratings and switching duty
Rated operational current varies by voltage and duty: at 24 V the switch handles 6 A (general use) and 10 A under AC-15 (solenoid/contactor control); at 230 V it delivers 6 A general and 1.2 A AC-15; at 400 V it is rated 3 A general and 0.5 A AC-15. For higher-voltage applications, the AC-15 rating at 690 V is 1 A, and at 600 V it drops to 0.26 A — the inductive load switching capability falls off sharply above 400 V. The switch meets mirror contact requirements per IEC 60947-4-1 when used with 3RT2 contactors — meaning the NO contact cannot remain closed if the main contactor welds, a safety-critical feature for motor starter circuits.
Panel fit and wiring
Dimensions are 43.7 mm deep, 36 mm wide, and 37.5 mm high — the 36 mm width matches the standard S00/S0 contactor front profile, so it does not add panel width beyond the contactor itself. Snap-on mounting means no tools for attachment; the switch clips directly onto the contactor front, saving DIN rail space compared to a separate terminal-mounted block. Terminal capacity accepts 2x (0.5...1.5 mm²) solid/stranded or 2x (0.75...2.5 mm²) finely stranded with ferrule, or 2x (20...16) and 2x (18...14) AWG — enough for control-circuit wiring up to 2.5 mm².
Environmental and compliance
Rated IP20 on the front — protected against solid objects over 12 mm but not against moisture; suitable for dry indoor panel environments where the contactor itself provides the enclosure. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C, covering most industrial control cabinet conditions. Surge voltage resistance is 6 kV, and the product complies with RoHS substance prohibitions dated 10/01/2009.