The Siemens 3RT1026-1BE40 is a SIRIUS S0-frame power contactor. Rated motor power is 11 kW at 500 V and also 11 kW at 690 V under AC-3 duty — that's the rating that governs motor starting. For inching or reversing (AC-4), it handles 15.5 A at 400 V.
The 45 mm width (S0 frame) is the panel-space number. The main circuit uses screw-type terminals, accepting solid wire from 2x 0.5 mm² up to 2x 4 mm², or stranded up to 2x 10 mm². That's enough for the motor leads on an 11 kW load at 500 V — no need for crimp ferrules if you're running solid conductors. That's the selectivity decision for the panel builder.
The 11 kW at 500 V AC-3 rating is the one that decides if this contactor fits a given motor. It's not the absolute maximum current — that's 10 A at AC-12 (resistive) — but the motor-switching capability under inductive load. For a 500 V motor, 11 kW is roughly 16 A full-load current, so the contactor is sized with some headroom above that. The auxiliary contact ratings cover the control circuit: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V DC. That last one matters for DC control buses — many contactors have derated DC ratings, and this one is no exception.