Integrator's brief: what this contactor delivers
The Siemens SIRIUS 3RT1026-1BP40-1AA0 is a Size S0 power contactor rated for motor switching at 11 kW in AC-2 duty at 400 V — the standard category for slip-ring motor starting and reversing. Its AC-4 rating at 400 V is 15.5 A, covering plugging and inching applications where the contactor makes and breaks stalled-rotor current. For resistive loads (AC-12), it handles up to 10 A continuously. Mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022. The 45 mm width and 85 mm height keep it within a standard panel layout — three units per 135 mm section. IP20 on the front means finger-safe terminals when wired; the terminal body itself is IP00, so live parts are exposed behind the panel door. Screw-type terminals on the main circuit accept 2x (0.5 to 1.5 mm²) solid, 2x (0.75 to 2.5 mm²) stranded, or up to 2x 4 mm² max. AWG equivalents are 2x (16 to 12) solid and 1x 8 stranded. Strip and torque per Siemens standard — no special tooling needed beyond a Pozidriv #2.
Coordination and protection: what the ratings mean for your panel
Short-circuit coordination is defined for two assignment types. Type 2 coordination (no damage to the contactor after a fault) requires a gL/gG fuse rated 35 A. Type 1 coordination (contactor may need replacement after fault) allows a 100 A gL/gG fuse. This matters when you're sizing the upstream protective device — the 35 A limit for Type 2 keeps the contactor reusable after a downstream short. Rated for pollution degree 3, meaning it's suitable for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation. Operating temperature range is -25 to +60 °C, with a maximum altitude of 2 000 m without derating. Side-by-side mounting is permitted — no spacing required — which saves rail space in dense panels.
Coil and control: DC magnet data
The DC magnet coil draws 5.4 W during both closing and holding — a constant-power design that simplifies the control transformer sizing. At 24 V rated value the contactor switches 10 A; at 230 V rated value it switches 6 A. These are the utilization category ratings for the auxiliary contacts, not the main poles. Mechanical endurance is rated at 10 million operating cycles — typical for a SIRIUS S0 frame in cyclic duty. The reference code per DIN EN 81346-2 is Q, identifying it as a switching device in the plant documentation system.
Sourcing and lifecycle: current production, quoted to order
For a panel originally specified around the smaller 3RT1015-1BB42, the 3RT1026-1BP40-1AA0 shares the same S0 frame footprint and DIN rail mounting, so it drops into the same rail position. However, verify the coil voltage and auxiliary contact configuration against the original BOM — the 3RT1026-1BP40-1AA0 carries a DC magnet, while the 3RT1015-1BB42 may differ in coil supply.