What it is and where it fits
The Siemens 3RT1035-1BF44 is a SIRIUS power contactor in size S2, rated for switching motor loads up to 22 kW at 500 V in AC-3 duty. It also handles 18.5 kW at 400 V in AC-2 duty and 35 A at 400 V in AC-4 duty. The contactor mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, making it a direct fit for standard European control panels. Screw-type terminals on the main current circuit accept stranded conductors up to 2x 25 mm² and solid conductors up to 2x 4 mm².
Environmental and compliance data
The contactor is rated for pollution degree 3, suitable for industrial environments with conductive pollution. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The front face carries IP20 protection, while the terminal area is IP00. RoHS compliance is documented with a substance prohibitance date of 05/01/2012. Mechanical life is rated at 10,000,000 operations typical.
Mounting and integration notes
The 3RT1035-1BF44 measures 55 mm wide, 112 mm high, and 179 mm deep. It supports side-by-side mounting without derating, which simplifies dense panel layouts. The screw terminals accept solid conductors: 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), max 2x (0.75...4 mm²); stranded: 2x (0.75...25 mm²); and solid/stranded: 2x (0.75...16 mm²). Minimum permissible cross-section at 40 °C is 16 mm².