The Siemens 3RH2911-1XA04-0MA0 is a front-mounted auxiliary switch block in the SIRIUS family, delivering four normally-closed (NC) contacts for 3RT2 contactors and 3RH2 contactor relays. It snaps onto the device front via the standard fastening method, adding four isolated NC current paths — labelled 51/52, 61/62, 71/72, 81/82 — without expanding the panel footprint beyond the 36 mm width of the base unit.
Switching capacity and contact reliability
Rated for 10 A maximum, with the AC-15 utilization category carrying 1 A at 690 V — the figure that governs inductive solenoid and contactor coil switching in control circuits. The DC switching curve is steep: 10 A at 24 V, 6 A at 125/230/250 V, 3 A at 400 V, and 0.26 A at 600 V. For AC loads at 60 V it handles 4.7 A; at 110 V, 3 A; at 220 V, 1.2 A; at 440 V, 0.5 A. The contact reliability spec — one faulty switching per 100 million operations at 17 V, 1 mA — means this block is trustworthy for PLC-level signal feedback even in low-energy circuits.
Mechanical endurance and environmental limits
Rated for 10 million operating cycles typical mechanical service life, so it outlasts the base contactor in most cyclic applications. The operating temperature range of -25 to +60 °C covers unheated enclosures and warm panel interiors; storage range extends to -55 to +80 °C. Insulation voltage is 690 V at pollution degree 3, with a 6 kV rated surge voltage resistance — sufficient for 400/480 V line-connected control circuits without additional suppression.
Termination and wiring
Screw-type terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with ferrule, or 2x (20 to 16 AWG) and 2x (18 to 14 AWG) for solid/stranded. The front face carries IP20 protection — finger-safe once wired, but not rated for washdown. Depth is 43.7 mm, height 37.5 mm, so it stays within the envelope of the host contactor or relay.