The Siemens 3RT1025-3BB44-3MA0 is a SIRIUS power contactor in the size S0 frame, designed for switching motor loads and resistive circuits in industrial control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, with a 45 mm width that fits standard enclosure layouts. Rated for AC-2 duty at 7.5 kW and AC-4 at 15.5 A, both at 400 V, this contactor handles squirrel-cage motor starting and plugging/reversing applications. The 24 VDC coil draws 5.4 W holding power, with switching capacity rated at 10 A at 24 VDC and 0.3 A at 220 VDC. Operating temperature range is -25 to +60 °C, with pollution degree 3 for industrial environments. The front face carries IP20 protection; the terminal area is IP00, so panel builders should account for clearance when wiring.
Mounting and Integration
Snap-on mounting onto 35 mm DIN rail per EN 50022 is standard; screw mounting is also supported. Side-by-side mounting is permitted with 6 mm clearance to adjacent devices, allowing dense panel layouts without derating. Screw-type terminals on the main circuit accept 2x (0.25 to 2.5 mm²) solid or stranded, up to 2x 10 mm² maximum. AWG equivalents are 2x (16 to 12) and 2x (14 to 10). The two instantaneous auxiliary contacts are rated for AC-12 at 10 A maximum.
Ratings and Coordination
Motor power ratings: 10 kW at 500 V and 11 kW at 690 V. For short-circuit coordination, type 1 requires a gL/gG fuse rated 63 A; type 2 requires 25 A. Mechanical life is rated at 10 million operations typical. The coil power factor range is 0.8 to 1.1. Maximum operating altitude is 2,000 m. Reference code per DIN EN 81346-2 is Q.