What it is and where it fits
The Siemens SIRIUS 3RT1017-2WB42 is a size S00 power contactor with a 24 VDC coil, built for switching motor loads in control panels. It snaps onto a 35 mm DIN rail per DIN EN 50022 or screws directly to a backplate — whichever your panel build calls for. At 45 mm wide and 73 mm deep, it fits standard 45 mm slot spacing; side-by-side mounting is allowed with zero gap, so you can pack multiple units across a DIN rail without worrying about derating from heat buildup.
Ratings that matter for the buyer
The coil pulls 1.4 W both closing and holding — no extra inrush to size your 24 VDC supply around. Pick-up is at 85% of rated voltage (20.4 V), drop-out at 185% (44.4 V), so it stays latched through a saggy bus but drops cleanly on overvoltage. Main contact ratings: 10 A at 24 V (AC-12), 8.5 A at 400 V (AC-4), and 5.5 kW motor load at 500 V or 690 V (AC-3). That 5.5 kW at 690 V is the same power as at 500 V — the contactor's thermal capacity, not voltage, is the limit here. For type 2 coordination, protect with a 20 A gL/gG fuse; type 1 allows 35 A. Mechanical life is 30 million operations — a fast mover for high-cycle applications like conveyor or pump control. The built-in varistor surge suppressor handles coil transients, so you don't need an external snubber.
Mounting and wiring
Spring-loaded terminals on the main circuit accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). Strip length is 8 mm — standard for this terminal family. The terminals are IP20 rated, so finger-safe inside a panel. Operating temperature range is -25 to +60 °C, with a maximum operating altitude of 2000 m. Pollution degree 3 means it's suited for industrial environments with conductive dust or humidity — typical for a food-and-beverage or automotive plant floor.