What it is and what it does
The 3RT2017-2KG42: This is a Siemens SIRIUS coupling contactor, size S00, designated for switching loads in 24 V DC control circuits — 10 A at 24 V DC rated value. The spring-type terminals (push-in style) accept solid or stranded wire from 0.5 to 4 mm², which saves wireman time on the panel build compared to screw terminals. The contactor sits in the SIRIUS modular system, so it integrates with overload relays and other SIRIUS components on the same DIN rail.
Mounting and panel fit
Mounts via screw or snap-on onto a standard 35 mm DIN rail per DIN EN 60715. The 45 mm width (3 width units on a standard DIN rail) is compact — you can pack several of these in a row. Mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/- 22.5°. That matters when you're fitting into a tight enclosure or a swing-panel layout. Spacing clearances: 10 mm upwards, downwards, and forwards; 6 mm at the sides. Ambient operating range is -25 to +60 °C, storage -55 to +80 °C.
Switching performance and duty cycles
Rated for AC-3 motor switching at up to 750 operations per hour maximum, and AC-4 (inching/plugging) at 250 ops/h. The DC coil operates with a pick-up/drop-out time of 7 to 20 ms, and arcing time is 10 to 15 ms. For a coupling contactor, the mechanical life is typical 30 million operations — that's a long service interval before you're swapping it out on a PM schedule.
Ratings across voltages
The contactor carries a range of DC-13 rated currents depending on the control voltage: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V. At 400 V AC it's rated 3 A. At 230 V it's rated 2 hp. No auxiliary switch is built in — if you need aux contacts, you add them separately from the SIRIUS system.