What it is and where it fits
The Siemens SIRIUS 3RT1035-1AL20-1AA0 is a Size S2 power contactor rated for motor switching up to 22 kW at 500 V in AC-3 duty and 18.5 kW at 400 V in AC-2 duty. It mounts on a 35 mm DIN rail per EN 50022, with screw-type terminals on the main circuit. The front face carries an IP20 rating; the terminals themselves are IP00, so panel builders should account for finger-safe shrouding or separation in the enclosure layout.
Key ratings and what they mean for your panel
The AC-3 rating of 22 kW at 500 V governs motor switching for standard squirrel-cage induction motors — that's the figure to match against your motor nameplate. At 400 V AC-2 (slip-ring motors or heavy jogging duty) it delivers 18.5 kW, and at 690 V it handles 11.4 kW. The coil draws 10 A at 24 V rated value, 6 A at 230 V, and 3 A at 400 V — these are the pickup currents; the holding current is lower. Mechanical life is rated at 10,000,000 operations typical, with maximum operating rates of 1,200 cycles/hour in AC-1, 1,000 in AC-3, and 300 in AC-4. The pollution degree 3 rating means it's suitable for industrial environments with conductive pollution; side-by-side mounting is permitted without derating.
Termination and wiring
Main circuit terminals accept solid conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and max 2x (0.75 to 4 mm²). Stranded conductors: 2x (0.75 to 25 mm²) for the main circuit. The coil terminals accept 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded. All are screw-type — no spring-cage option on this variant. The 55 mm width and 112 mm height fit standard S2 contactor spacing; depth is 115 mm including coil terminals. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.