What this SIRIUS auxiliary contactor does
The Siemens 3RH1131-2BB40-ZW98 is a SIRIUS auxiliary contactor — a compact switching block that extends the control-circuit contacts on a larger contactor or starter, or stands alone for signal routing in a panel. The 24 VDC coil draws 3.2 W closing and holding, so the power supply budget is flat: no inrush spike to size for. AC-12 rated at 10 A maximum, it handles pilot-duty loads like PLC inputs, relay coils, and indicator lamps without derating concerns at 24 V. Three normally-open instantaneous contacts (plus zero delayed, lagging, or make-before-break) give you a clean set of N.O. signal paths. Contact reliability is spec'd at one incorrect switching operation per 100 million at 17 V, 1 mA — meaning it's trustworthy for low-energy PLC-level signals, not just power circuits.
Mounting and integration
Size S00 footprint: 45 mm wide, 60 mm tall, 73 mm deep. Fastens with screw or snaps onto DIN rail. Mounting position is flexible — +/-180° rotation on a vertical surface, plus +/-22.5° tilt forward and backward — so it fits tight enclosures without forcing a specific orientation. IP20 on the front means it's protected against finger contact; fine inside a locked panel, not for washdown zones. Solid conductors 0.25 to 2.5 mm² fit the screw terminals. The 73 mm depth is shallow enough to leave wire-bending space in a 200 mm deep enclosure.
Switching capacity across voltages
Rated operational currents vary by voltage and duty: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V. At 110 V it's rated 1 A; at 220 V, 0.27 A. These are the AC-12 values for resistive/pilot duty — use them for sizing the contactor's load circuit, not the coil circuit.