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
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.
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. 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.
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. Depth is 43.7 mm, height 37.5 mm, so it stays within the envelope of the host contactor or relay.