What it is and what it does
The Siemens 3RH1131-1BA40 is a SIRIUS auxiliary contactor — a switching block that extends the control-circuit reach of a main contactor or provides standalone signal switching in a panel. It carries 3 normally-open instantaneous contacts rated 10 A at AC-12 (resistive loads up to 400 V), which is the current it can make and break reliably in control circuits like PLC outputs, relay coils, or indicator lamps.
Panel fit and mounting
Size S00 frame — 45 mm wide, 57.5 mm tall, 72 mm deep — fits standard DIN-rail enclosures and mates with Siemens S00 contactors (e.g., 3RT1015 or 3RT1016 series) for a ganged auxiliary block. Screw and snap-on mounting means it clips onto the rail or screws directly to a backplate; no special tooling needed. Wire capacity: accepts 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or 2x 4 mm² solid conductors per terminal. Side clearance is 0 mm — zero gap required between adjacent devices — so it packs tight on the rail without derating for heat buildup in normal control loads.
Electrical ratings and environment
The 3 NO contacts are instantaneous only — no leading, lagging, delayed, or make-before-break options on this variant. AC-12 switching capacity at 230 V is 6 A, at 400 V is 3 A, and at 690 V is 1 A. For DC control circuits, the contacts handle 10 A at 24 V, 1 A at 110 V, and 0.27 A at 220 V — the DC ratings drop sharply with voltage due to arc extinction limits. Coil power: 3.2 W closing and holding at DC, with a surge voltage resistance of 6 kV. Operating temperature range is -25 to +60 °C; storage and transport range is -55 to +80 °C. Pollution degree 3 (conductive pollution or dry non-conductive that becomes conductive due to condensation), typical for industrial control panels not in sealed clean rooms. Shock resistance: 10g / 5 ms and 5g / 10 ms. Maximum operating altitude 2 000 m without derating.