What it is and what it switches
The Siemens SIRIUS 3RH1911-1HA13 is a 4-pole auxiliary switch block (1 normally open + 3 normally closed contacts) designed for use with SIRIUS contactor relays and power contactors. It mounts via snap-on directly onto the contactor or onto a 35 mm DIN rail, occupying a 36.5 mm width slot in the panel. The DC-13 switching curve tells you exactly what it handles at each voltage: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. For AC-15 duty, it delivers 1 A at 690 V. This is the rating that governs whether the block clears the inductive load of a DC solenoid or AC contactor coil without welding the contacts. Contact reliability is specified at one faulty switching per 100 million operations at 17 V, 1 mA — a low-level signal rating that matters when the auxiliary contacts feed a PLC input rather than a power circuit. Mechanical service life is typical 10 million switching cycles.
Lifecycle and replacement
The 3RH1911-1HA13 is a phased-out product. The official Siemens successor is the SIRIUS 3RH2 series, with preferred successor type 3RH2911-1HA13. For new designs or BOM freeze replacements, the 3RH2911-1HA13 is the drop-in intended by the manufacturer.
Mounting and wiring
Snap-on mounting onto the contactor or 35 mm DIN rail. Dimensions: 36.5 mm wide, 41.5 mm deep, 37.5 mm high. Screw-type terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16) and 2x (18 to 14) AWG. Rated insulation voltage is 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV. IP20 protection on the front — suitable for enclosed panel use, not for washdown environments. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.