What it is and where it fits
The Siemens SIRIUS 3RT2023-1BF40 is a power contactor in the S0 frame size, designed for switching motor loads and resistive loads in control panels. It mounts on a 35 mm DIN rail per DIN EN 60715, with screw and snap-on fastening, and accepts a wide mounting position range — ±180° rotation on a vertical surface and ±22.5° tilt forward/backward. Rated control supply voltage is 110 V AC, with an operating range factor of 0.8 x to 1.1 x the rated value. The magnet coil uses screw-type terminals.
Key ratings and what they mean for the buyer
Main contacts are rated for 16 A to 8 A (likely AC-3 duty), which covers common small-to-medium motor loads up to about 7.5 kW at 400 V. The auxiliary switch is present, with contact ratings that vary by voltage: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. At 230 V the contactor is rated for 1 hp — a direct fit for fractional-horsepower motors common in conveyor and pump applications. Switching frequency reaches 1 000 operating cycles per hour for AC-1, AC-2, AC-3, and AC-3e duty, dropping to 300 cycles/h for AC-4 (plugging/reversing). Mechanical service life is typical 10 000 000 operations. The DC operating time (including arcing) is 15–18 ms, with an arcing time of 10 ms — fast enough for most sequencing applications. Wire range for main and auxiliary circuits: solid or stranded 1 … 10 mm², with fine-stranded (ferruled) 2x (0.5 … 1.5 mm²) or 2x (0.75 … 2.5 mm²). Clearance distances: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side — important when laying out DIN-rail density in a panel.