The Siemens 3RH2131-1AR60 is a SIRIUS auxiliary contactor in size S00, carrying 3 normally open instantaneous contacts. It is rated for 400 V AC at 50 Hz and 400-440 V AC at 60 Hz, with a 24 V rated current of 10 A — enough to switch small control loads or signal the PLC that a main contactor has pulled in. The 3 NO configuration means this block adds three independent make contacts to the base device, useful for feedback or interlock circuits on a motor starter or contactor assembly.
The 3 NO contacts are rated for 10 A at 24 V rated value (resistive load curve) and derate to 3 A at 110 V, 1.2 A at 220 V, and 0.26 A at 600 V — so the actual current capability drops fast as voltage climbs. For a 24 VDC PLC input circuit, all three contacts can switch the full 10 A; for a 230 VAC pilot light or valve, each contact handles 1.2 A. The arcing time runs 10-15 ms, which matters if you are coordinating with fast solid-state inputs that might see a false edge. The S00 footprint (45 mm wide, 73 mm deep, 57.5 mm high) fits the standard SIRIUS contactor grid, so it clips directly alongside a 3RT2 main contactor without extra adapter plates.
Integration notes
Wiring accepts 2x 0.5-1.5 mm² solid or stranded, 2x 0.75-2.5 mm², or 2x 4 mm² — spring-cage terminals, strip length around 8-10 mm. The 30 million mechanical cycles typical life means it outlasts most main contactors it signals — fit it and forget it for the panel's service life.