SIRIUS 3RT2025-1BF40 — Size S0 Power Contactor, 110 V Coil
The Siemens SIRIUS 3RT2025-1BF40 is a size S0 power contactor with a 110 V coil, screw-type terminals, and a rated operating current that depends on the utilization category — the AC-3 switching frequency is rated at 1 000 operations per hour, while AC-4 drops to 300 1/h, reflecting the heavier switching duty of inching or plugging. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, and the mounting position allows +/-180° rotation on a vertical surface plus +/-22.5° tilt forward and backward — useful when panel layout forces an unconventional orientation. The auxiliary switch is present, and the contactor's mechanical life is typically 10 000 000 operations. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C.
Dimensions, Wiring, and Clearances
The 3RT2025-1BF40 measures 85 mm high, 45 mm wide, and 107 mm deep — the depth figure matters when planning gland-plate clearance or enclosure depth. Solid and stranded wire from 1 to 10 mm² is accepted at the main terminals; auxiliary contacts accept 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²). Minimum clearances to adjacent components: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. These are the spacing rules for heat dissipation and arc containment — pack tighter and you derate the switching capacity.
Auxiliary Contact Ratings at 24 V Through 230 V
The auxiliary switch is rated for the following continuous currents at the respective voltages: 10 A at 24 V, 2 A at 48 V, 2 A at 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. The 400 V rating is the one to watch if you are switching a control transformer primary — it is derated significantly from the 24 V figure.