The Siemens 3RT1026-1BB44-1AA0 is a SIRIUS S0-frame power contactor rated for 11 kW at 400 V in AC-3 duty and the same 11 kW at 690 V, making it a fit for three-phase motor loads up to that power class across standard European supply voltages. The coil is 24 VDC, drawing 5.4 W on pickup and 5.4 W holding — a constant-hold design that simplifies the DC supply sizing since there is no dropout between seal-in and hold.
Motor switching and coordination
Beyond the AC-3 motor rating, the contactor is rated for AC-4 duty at 15.5 A at 400 V — the category for plugging and inching where the contacts make and break stalled-rotor currents. AC-2 at 400 V also carries 11 kW, covering slip-ring motor starting. Short-circuit coordination is specified: type 1 coordination requires a 100 A gL/gG fuse; type 2 coordination requires a 35 A gL/gG fuse. This lets the panel designer choose between simpler replacement after a fault (type 1) or minimal contact damage (type 2) depending on the line's uptime requirements.
Auxiliary contact block and coil data
The contactor carries 2 instantaneous auxiliary contacts (NO/NC configuration not specified in the base code — the 1AA0 suffix typically indicates a specific auxiliary block variant; verify the contact arrangement against your schematic). The coil's DC switching capacity is rated at 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — these are the maximum currents the auxiliary contacts can switch in DC control circuits, which matters when driving PLC outputs or relay loads. Terminals accept solid or stranded conductors: main circuit terminals take 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), or max 2x 10 mm²; auxiliary circuit terminals take 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²). AWG equivalents are 2x (16 to 12), 2x (14 to 10), and 1x 8 for the main circuit. The screw-type terminals are standard for panel wiring.
The active lifecycle means no special surplus-channel search is needed — it is a straightforward BOM line item.