The Siemens 3RT1035-1BM40 is a SIRIUS S2-frame power contactor — the workhorse for motor switching in control panels that already run on 35 mm DIN rail per EN 50022, with screw-and-snap-on mounting that drops into the same footprint as earlier S2 builds. Rated 22 kW at 500 V in AC-3 duty, it handles the standard induction motor curve for pumps, conveyors, and compressors without oversizing the contactor. At 55 mm wide and 130 mm deep, it leaves room alongside other S2 devices on the rail; side-by-side mounting is supported, so no derating for zero-gap packing in a tight enclosure.
Solid wire accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) and max 2x (0.75 to 4 mm²); stranded goes up to 2x 25 mm².
The IP20 front and IP00 terminal area are typical for enclosed panel mounting — no special washdown rating, so keep it inside the cabinet.