The Siemens SIRIUS 3RH6131-1BM40 is a contactor relay — a control-circuit switching device, not a power contactor for motor loads. Its switching element configuration is identified as 31 E, meaning 1 normally-closed (NC) and 3 normally-open (NO) auxiliary contacts. This gives you four independent contact paths for interlocking, signaling, or logic functions in a control scheme. The coil is rated for DC control voltage at 220 V, drawing 4 W during both closing and holding — a constant-power coil design that simplifies the DC supply sizing. The 6 kV rated surge voltage resistance means the coil insulation withstands the transients common on 220 V DC control buses in industrial panels.
That covers most panel layouts without needing a special bracket. Dimensions are 45 mm wide, 57.5 mm high, 73 mm deep — the S00 footprint. The screw-type terminals for auxiliary and control circuits accept 2x (0.5 to 1.5 mm²) solid/stranded, 2x (0.75 to 2.5 mm²), or 2x 4 mm². For AWG, that translates to 2x (20–16), 2x (18–14), or 2x 12 AWG. Finely stranded wire with core-end processing (ferrules) also fits the same cross-sections.
Switching ratings and contact reliability
At 24 V the contacts carry 6 A; at 110 V, 3 A; at 220 V, 1.2 A; at 230 V, 10 A; at 400 V, 3 A; at 690 V, 1 A. The 10 A at 230 V rating is the highest thermal current — that's the resistive load (AC-12) figure. For DC switching, the operating frequency maxes at 1 000 operations per hour for both DC-12 and DC-13. The mechanical endurance is 30 million switching cycles typical for the contactor relay alone, and 10 million typical when an auxiliary switch block is added.