The Siemens 3RH1911-1FA31 is a SIRIUS auxiliary switch with 3 normally open instantaneous contacts, designed to snap onto the front of S00-size contactor relays and power contactors. It's the add-on block you grab when a 3RT1 contactor needs more N.O. feedback or pilot-duty signaling without eating up extra DIN rail. Rated for AC-15 and DC-13 switching duty, the contact block handles 6 A at 24 V and 10 A at 24 V rated value, stepping down to 0.3 A at 220/250 V AC and 0.26 A at 600 V — so it's fine for PLC inputs, relay coils, and indicator lamps across a wide control-voltage spread. The AC-15 rating at 690 V holds at 1 A, enough for most 480 V to 690 V pilot circuits you'll find on European-sourced machines.
Snaps onto the front of a 3RT1 S00 contactor or contactor relay — no tools, no DIN-rail space lost. The block measures 36.5 mm wide, 37.5 mm high, and 41.5 mm deep, fitting flush against the contactor body. Terminals accept 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²) with ferrules; AWG equivalents are 2x (20 to 16) and 2x (18 to 14). The mechanical life is rated for 10 million operating cycles typical, and contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — a solid spec for low-energy logic circuits where oxide buildup can cause intermittent faults.
The mirror contact feature per IEC 60947-4-1 is present when used with the 3RT1 contactor — that means the N.O. mirror contact mechanically reflects the main contact position, a requirement in safety circuits where you need positive indication that the power contacts have opened.
Substance prohibitance date references RoHS compliance effective July 1, 2006 — the part is RoHS-compliant.