The Siemens SIRIUS 3RH2911-2FB11 is a front-mounted auxiliary switch block for the 3RT2 contactor and 3RH2 contactor relay series. It provides one normally-open (leading) and one normally-closed (lagging) contact pair, wired to spring-loaded terminals that accept 2x (0.5...2.5 mm²) without ferrules or 2x (0.5...1.5 mm²) with core-end processing. The snap-on fastening method means it clips directly onto the contactor front face with no tools — a clean retrofit when you need extra signal feedback or interlocking on a motor starter.
The maximum thermal current is 10 A, but the real-world switching capacity depends on the voltage and load type. For AC-15 pilot-duty loads (solenoid valves, contactor coils, relays) at 24 V, the rated operational current is 6 A; at 230 V it's also 6 A, and at 400 V it drops to 3 A. For DC switching, the same contact set handles 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, and tapers to 0.26 A at 600 V. The AC-15 rating at 690 V is 1 A.
Mechanical life and environment
Rated for 10 million mechanical operating cycles typical, so it will outlast most contactors it rides on.