What it is and where it fits
The Siemens SIRIUS 3RT1017-1AP02-1AA0 is a size S00 power contactor with a 24 VDC coil, designed for switching motor loads in control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, and its 45 mm width and 57.5 mm height fit standard panel layouts. The front is rated IP20 for finger-safe access.
Key ratings and what they mean for your circuit
For motor duty, the AC-2 rating at 400 V is 5.5 kW — that covers squirrel-cage starting for pumps or fans. The AC-4 rating is 8.5 A at 400 V, which is the figure for reversing or plugging duty where the contactor makes and breaks stalled-rotor current. For control circuits, the 24 V rated current is 10 A, so it handles a bank of solenoids or a small transformer load. At 230 V the rating is 6 A; at 690 V it's 5.5 kW. Short-circuit coordination requires a gL/gG fuse: 20 A for type 2 coordination (no damage to the contactor), 35 A for type 1 (contactor may need replacement after a fault). This matters when you're sizing the branch protection.
Panel integration details
The screw terminals accept 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), or max 2x (0.75...4 mm²) solid/stranded. AWG equivalents are 2x (20...16), 2x (18...14), or 1x 12. Side-by-side mounting is allowed with a 6 mm gap to adjacent devices. Operating temperature range is -25 to +60 °C, and it's rated for pollution degree 3 (industrial environment). Maximum operating altitude is 2,000 m.