What it is and what it does
The Siemens SIRIUS 3RH1911-1FA11-ZW97 is an auxiliary switch block — a 1 NO + 1 NC contact block that mounts directly onto SIRIUS contactor relays and power contactors of size S00. It is designed for switching auxiliary circuits in control panels, providing feedback or interlock signals from the main contactor. Rated for a maximum of 10 A, it carries a surge voltage resistance of 6 kV and an insulation voltage of 690 V AC at pollution degree 3 — figures that confirm it is built for industrial control environments where transient overvoltages and dust are routine. Snap-on mounting onto 35 mm DIN rail (or directly onto the contactor) means panel integration is tool-less and the block occupies the same width as the S00 contactor — 36.5 mm — so it does not steal additional rail space.
Key ratings and what they mean for fit
The contact ratings are given per voltage: at 24 V it switches 6 A (AC-15/DC-13), at 230 V it switches 6 A, and at 400 V it switches 3 A. These are the values that govern real-world auxiliary circuit duty — a 10 A maximum does not mean you can pull 10 A at 400 V. Use the voltage-specific figure for your control voltage. Mechanical service life is 10 million switching cycles typical. Contact reliability is rated at 1 faulty switching per 100 million operations (at 17 V, 1 mA) — a strong low-level switching capability that matters for PLC inputs and solid-state loads. Screw-type terminals accept 2x (0.5…1.5 mm²) or 2x (0.75…2.5 mm²) with core-end processing, or 2x (20…16) and 2x (18…14) AWG. The IP20 front protection means it is suited for enclosed panel use only — not for washdown or outdoor exposure.