Integrator's spec recap — SIRIUS 3RT1026-1AG20-1AA0
The Siemens SIRIUS 3RT1026-1AG20-1AA0 is a size S0 power contactor rated for motor switching at 11 kW on 400 V in AC-2 duty, and 15.5 A in AC-4 duty at the same voltage — so it handles both slip-ring motor starting and plugging/reversing cycles without derating the main poles. Screw-type terminals on the main circuit accept up to 2x 10 mm² or 1x AWG 8, with a separate solid/stranded range of 2x (0.5 to 1.5 mm²) through max 2x (0.75 to 4 mm²) for auxiliary wiring.
Coordination and protection — what the ratings mean
For Type 1 coordination (contactor may need replacement after fault), the fuse can go to 100 A gL/gG — the 35 A path is what you'd spec for minimal downtime on a motor branch. Rated operational power reaches 11 kW at both 500 V (50 Hz) and 690 V (60 Hz), so the contactor is not voltage-limited within that band — the motor full-load current determines the selection, not the voltage step. Auxiliary contact ratings: 10 A at 24 V, 6 A at 230 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V — the DC switching curve drops fast above 60 V, so verify the control voltage if running DC pilot circuits above that.
No official successor or replacement order code is published; this is the active variant. If you are matching a BOM line that specifies 3RT1026-1AG20-1AA0, it is the direct fit.
Panel and environmental fit
Dimensions: 85 mm high, 45 mm wide, 91 mm deep — fits S0 contactor cutouts in standard IEC enclosures. Side-by-side mounting is permitted (no derating gap needed for thermal stacking in open air). Altitude limit 2 000 m without derating. Front protection IP20 (finger-safe terminals when wired); the terminal body itself is rated IP00 — so the contactor must be mounted inside an enclosure that provides the overall panel IP rating.