SIRIUS S0 power contactor — 3RT2025-1BM40
The Siemens 3RT2025-1BM40 is a SIRIUS S0-frame power contactor with screw-type coil terminals and an integrated auxiliary switch. It mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715, fitting into standard panel layouts with a 45 mm width, 85 mm height, and 107 mm depth. Rated for motor loads up to 3 hp at 230 V, this contactor handles AC-3 switching at up to 1,000 operations per hour, with AC-4 duty derated to 300 operations per hour. The auxiliary contact set carries 10 A at 24 V DC, 2 A at 48 V DC, 1 A at 110 V DC, 0.3 A at 220 V DC, and 3 A at 400 V DC — check your control circuit voltage against these curves.
The S0 frame accepts solid or stranded conductors from 1 to 10 mm² on the main contacts, with auxiliary terminals taking 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²). The coil dropout time at DC is 15 to 18 ms, arcing time 10 ms — factor these into your control logic timing if sequencing multiple contactors.