The Siemens 3RH1122-2BP40 is a SIRIUS auxiliary contactor in size S00, with a 230 V rated coil and two normally-open instantaneous contacts. It mounts via screw or snap-on onto a DIN rail, fitting into a 45 mm wide slot in the panel. The IP20 front protection means it's suited for enclosed control panels where no washdown or dust ingress is expected at the operator interface.
Contact ratings and what they mean for your circuit
The contact ratings are given per voltage: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. These are thermal current ratings for the auxiliary contacts — they define the maximum continuous current the contacts can carry at each voltage level. For a 24 VDC control circuit, the 10 A rating gives plenty of headroom for pilot lights, relays, or PLC inputs. At 230 V, the 6 A rating handles most contactor coils and small motor starters. The 1 A at 690 V rating is useful for higher-voltage control schemes in industrial environments. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — this matters for low-energy signal switching where oxide films on silver contacts can cause intermittent faults. The mechanical life is rated at 30 million operations typical, which is standard for a SIRIUS-size S00 auxiliary contactor used in high-cycle applications like conveyor interlocking or press controls.
Coil and environmental specs
The magnet coil draws 3.2 W DC for both closing and holding — a single-wattage coil, meaning no separate economizer circuit needed. The coil is rated for 230 V, so it's a direct fit for standard European control voltages. Surge voltage resistance is 6 kV, which covers most industrial transient environments without external suppression. Operating temperature range is -25 to +60 °C, storage and transport from -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms, adequate for machine-mounted applications near presses or conveyors.
Mounting and wiring
Fastening is via screw and snap-on mounting — the standard DIN rail clip for size S00 contactors. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward, giving flexibility in tight enclosures. Terminal capacity is 2x (0.25 to 2.5 mm²) solid or 2x (24 to 14 AWG) for auxiliary contacts, using screw terminals. Depth is 73 mm, height 60 mm, width 45 mm — compact enough for dense panel layouts.