SIRIUS Size S0 power contactor, 110 VDC coil, spring terminals
The Siemens 3RT2025-2BF40 is a SIRIUS-brand power contactor in the Size S0 frame, rated for a 110 VDC coil with a pick-up threshold of 0.8 x rated value. The contactor carries spring-type terminals on both main and auxiliary circuits, accepting solid or stranded conductors from 1 to 10 mm², or 2x (0.5 to 2.5 mm²) for the auxiliary wiring. The auxiliary switch block is factory-fitted (18... 8 configuration — likely 1 NO + 1 NC, though the exact count should be verified against the nameplate). DC switching ratings for the aux contacts are: 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. These are the make/break limits for DC-13 or similar inductive loads; for a 24 VDC PLC output driving a contactor coil, the 10 A rating gives ample headroom. Mechanical life is typical at 10,000,000 operations. Switching frequency depends on duty: up to 1,000 cycles/hour for AC-1, AC-2, AC-3, and AC-3e loads; drops to 300 cycles/hour for AC-4 (plugging / inching duty). The arcing time is 10 ms, and the DC dropout delay spans 15 to 18 ms — useful to know if you're sequencing contactors in a safety circuit.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width (3 TE on a standard DIN rail) and 102 x 107 mm (H x D) footprint fit a standard panel layout. Clearance distances: 10 mm upward, 10 mm forward, 10 mm downward, 6 mm at the sides — these are the minimum air gaps to adjacent metalwork or other devices for heat dissipation and arc containment. Mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/-22.5° on a vertical surface. This covers most cabinet layouts without derating, though the -25 to +60 °C operating range and -55 to +80 °C storage range should be respected.