The Siemens 3RT1026-3AF00 is a Size S0 SIRIUS power contactor with three normally-open main contacts, rated for motor switching at 11 kW in AC-2 duty at 400 V. That AC-2 rating covers wound-rotor motors where inrush isn't the full locked-rotor spike — think crane hoists or conveyor drives that need smooth acceleration. For the tougher AC-4 plugging/reversing duty, it's good for 15.5 A at 400 V. The screw-type main terminals accept 2x 10 mm² or a single 8 AWG conductor.
The 45 mm width and 85 mm height leave room for a side-by-side ganged assembly — Siemens allows it. Keep 6 mm clearance at the sides for heat dissipation. Front-side protection is IP20, so it's safe from accidental finger contact in an enclosed panel; the terminals themselves are IP00, meaning live parts are exposed if the panel door's open. Pollution degree 3 means it's built for the conductive dust and humidity you find in industrial enclosures, not a clean office environment.
The coil operates at 50 Hz with a voltage tolerance of 0.8 to 1.1 times the rated value. At 24 V the contactor draws 10 A inrush; at 230 V it's 6 A, and at 400 V it drops to 3 A. For DC control circuits, the 24 V coil pulls 10 A, while the 220 V DC coil pulls 0.3 A. The mechanical life is a typical 10 million operations — that's a lot of cycles before the armature wears.
Short-circuit coordination
That's the one to use if you want the contactor back in service after a short without replacing it. Type 1 coordination allows a 100 A gL/gG fuse — the contactor may be damaged and need replacement, but the fault clears. The difference matters for uptime: Type 2 keeps the line running faster after a short.