Auxiliary contactor for control-circuit switching
The Siemens 3RH1131-2BG40 is a SIRIUS auxiliary contactor in the S00 frame size, carrying 3 instantaneous normally-open contacts. It is designed for control-circuit switching — signaling, interlocking, and logic-level loads — not motor power. The contacts are rated 10 A at 24 V, 6 A at 230 V, and 1 A at 690 V, covering the common AC and DC control voltages found in industrial panels. Mechanical endurance is rated at 30 million switching operations typical, and contact reliability is specified as one incorrect switching per 100 million operations at 17 V, 1 mA — a figure that matters for PLC-level dry circuits.
DIN-rail fit and panel integration
Mounting is via screw or snap-on onto standard DIN rail. The 45 mm width (one standard module) and 73 mm depth leave room for gland plates and side-by-side contactor stacks. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the panel layout forces an unconventional orientation. Pollution degree 3 rating means it tolerates conductive dust and humidity typical of industrial enclosures without conformal coating.
Coil and wiring
The DC magnet coil draws 3.2 W for both closing and holding — no inrush spike to size a power supply around. Terminals accept 2x (0.25... 2.5 mm²) solid or stranded, or 2x (24... 14 AWG). Surge voltage resistance is rated at 6 kV, so the contactor handles the transients from adjacent inductive loads without additional snubbers in most panels.
Sourcing and availability
The 3RH1131-2BG40 is sourced to order through independent distribution. Availability and current pricing are confirmed at quote time against an RFQ.