What it is and what it does
The Siemens SIRIUS 3RT1024-1BB40-ZW98 is a Size S0 power contactor with a 24 VDC magnet coil drawing 5.4 W for both closing and holding. It switches motor loads in AC-3 duty up to 7.5 kW at 400 V and 500 V, and handles AC-4 reversing duty at 12.5 A. For resistive or general-purpose loads (AC-1), the contact rating reaches 10 A at 24 V. The coil holds at 24 VDC nominal; dropout happens below the listed minimum operating threshold.
Mounting and integration
Mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022. The 45 mm width and 85 mm height fit a standard panel footprint; depth is 101 mm, so account for that behind the gland plate. Side-by-side mounting is allowed with 6 mm clearance to adjacent devices. Pollution degree 3 rating means it's suited for industrial environments with conductive dust or moisture — no extra conformal coating needed for typical panel conditions.
Wiring and termination
Main current circuit uses screw-type terminals. Accepts solid conductors 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). For stranded or multi-stranded wire, it takes 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), max 2x 10 mm². AWG equivalents: 2x (16 to 12), 2x (14 to 10), 1x 8. Short-circuit coordination: Type 2 requires a 25 A gL/gG fuse; Type 1 allows up to 63 A gL/gG.