The Siemens SIRIUS 3RT1026-3KB44-0LA0 is a size S0 power contactor rated for 11 kW at 400 V in AC-3 duty, making it a fit for switching three-phase motor loads up to that power level on standard 400 V networks. The 24 VDC coil draws 23 W on pickup and holds at 7 W, which matters for DC-supply sizing in a panel — the inrush isn't trivial, so factor it into your 24 V bus budget.
Terminals and wiring
Main power circuit lands on screw-type terminals accepting 2x (1... 2.5 mm²), 2x (2.5... 6 mm²), or max. 2x 10 mm² stranded — covers common motor cable sizes up to about 8 AWG. The auxiliary and control circuit uses spring-loaded terminals rated for 2x (0.25... 2.5 mm²) solid or 2x (24... 14) AWG. That split (screw for power, spring for control) is a practical choice: power wires get a positive clamp you can torque, control wires snap in fast during commissioning.
Mounting and environment
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, and side-by-side mounting is allowed — no derating gap needed between units in a row, which saves rail space in dense panels. Ambient range is -40 to +70 °C, so it'll sit in an unheated enclosure or near a hot machine wall without issue. Pollution degree 3 means it's rated for industrial environments with conductive contamination; IP20 on the front, IP00 at the terminals — keep live parts behind a panel door or cover.
Coordination and protection
For type 2 coordination (no welding after a fault) the required upstream fuse is gL/gG 35 A; for type 1 coordination (welding allowed, but no fire risk) it's 100 A. That's the spec to hand your panel-builder when they size the branch circuit. The built-in varistor surge suppressor clips coil-induced spikes — no external snubber needed on the 24 VDC control line.