What it is and what it does
The Siemens SIRIUS 3RT1026-1AK00 is a size S0 power contactor with three normally open main contacts, designed for switching motor loads in industrial control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, fitting a standard panel footprint at 45 mm wide. Rated for AC-2 duty at 11 kW on a 400 V supply, this contactor handles slip-ring motor starting and reversing. For AC-4 inching and plugging duty at 400 V, the operating current is 15.5 A. It also carries 11 kW at both 500 V and 690 V, covering higher-voltage motor circuits common in export or heavy industrial panels.
Integration and mounting
The 45 mm width and 85 mm height fit a standard S0 footprint. Depth is 91 mm, which includes clearance for the screw-type terminals on the main circuit. Side-by-side mounting is permitted, so multiple contactors pack tightly on the rail without forced spacing — useful when building a motor control center bucket. Main circuit terminals accept solid or stranded conductors: 2x (1 to 2.5 mm²) or 2x (2.5 to 6 mm²), with a maximum of 2x 10 mm². For AWG, that's 2x (16 to 12) or 2x (14 to 10), max 1x 8 AWG. The front face carries an IP20 rating; the terminal area itself is IP00, so gland-plate planning should keep live parts protected inside the enclosure.
Coordination and protection
For Type 2 coordination (no damage to the contactor after a short circuit), the required upstream fuse is gL/gG 35 A. Type 1 coordination (contactor may need replacement after a fault) allows a 100 A gL/gG fuse. The pollution degree is 3, meaning it's rated for the conductive environment inside a typical industrial enclosure. Mechanical endurance is rated at 10 million operations, so this contactor suits applications with moderate cycling — conveyors, pumps, fan starters — rather than high-speed indexing or servo duty.