Siemens 3RH1131-1BB40-ZW98 SIRIUS Auxiliary Contactor — 24 V DC, S00 Frame
The Siemens 3RH1131-1BB40-ZW98 is a SIRIUS auxiliary contactor in the compact S00 frame size, built for switching control and signal circuits in motor control centers and panel builds. The 24 V DC coil pulls in at 0.8 of rated voltage and holds at 3.2 W — a steady-state draw that stays within the typical 24 VDC power supply budget for a PLC output card or control transformer. Three normally-open and one normally-closed instantaneous contacts handle the auxiliary switching; the contact reliability spec (one failure per 100 million operations at 17 V, 1 mA) means this part is suited for dry-circuit signal switching where oxide film on bare contacts can cause intermittents. Rated operational currents scale with voltage: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 1 A at 690 V. That 10 A at 24 V is the figure to watch when interposing between a 24 VDC PLC output and a larger contactor coil — the auxiliary contactor can handle the inrush without welding. The 690 V, 1 A rating confirms it can switch a 690 VAC control circuit if the panel uses that voltage class.
Panel Fit and Mounting
At 45 mm wide, 57.5 mm tall, and 72 mm deep, the S00 frame fits standard DIN-rail spacing. Screw and snap-on mounting means it clips onto a 35 mm DIN rail and can also be screw-fixed to a backplate. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward or backward — useful when fitting into a crowded gland plate area where the contactor must sit at an angle to clear wire ducts. Terminals accept solid conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or 2x 4 mm². AWG equivalents are 2x (20–16), 2x (18–14), and 1x 12. That covers the common control wire sizes for panel wiring — 1.5 mm² for most signal runs, 2.5 mm² for longer coil feeds where voltage drop is a concern. The IP20 front protection means tools and fingers stay out of the live terminals when the panel door is open, but the contactor itself is not sealed against washdown.
Lifecycle and Sourcing
For a BOM freeze or second-source gate, the closest functional peer in the SIRIUS line is the 3RH2122-1BA40 — same S00 frame, same 24 V DC coil, but with a different contact arrangement (2 NO + 2 NC versus the 3 NO + 1 NC on this part). The 3RH2122-1BA40 will drop into the same DIN-rail footprint and wiring pattern, but the contact count difference means a controls drawing review if the spare NO or NC is used for a safety circuit.
Environmental and Mechanical Limits
Operating temperature range is -25 to +60 °C; storage and transport extend to -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms — adequate for panel-mounted gear in industrial machinery but not rated for direct mounting on a vibrating pump skid. Pollution degree 3 means the contactor is designed for conductive pollution environments typical of control panels without hermetic sealing. Coil closing and holding power are both 3.2 W DC. Surge voltage resistance is rated at 6 kV.