Siemens SIRIUS 3RT1025-1AP04-1AA0 — Power Contactor, Size S0, 7.5 kW at 400 V
The Siemens SIRIUS 3RT1025-1AP04-1AA0 is a 3-pole power contactor in the size S0 frame, rated for 7.5 kW motor switching at 400 V AC-3. That 7.5 kW figure is the AC-3 duty rating — the one that governs motor loads like pumps, fans, and conveyors. The AC-4 rating (15.5 A at 400 V) covers reversing or inching duty where the contactor makes and breaks the load under full current. For type 2 coordination, the required upstream fuse is a gL/gG 25 A; for type 1 coordination, a 63 A fuse is specified. The contactor mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, and the IP20 front-of-terminal protection means it's safe for open-panel installation as long as the live bus is behind a deadfront.
Mounting and Wiring — DIN Rail, Screw Terminals, Clearance
This contactor fits a 45 mm wide footprint on a 35 mm DIN rail (DIN EN 50022). Side-by-side mounting is allowed — no gap needed between units. The screw-type main terminals accept 2x (1–2.5 mm²) solid or 2x (2.5–6 mm²) stranded, with a maximum of 2x 10 mm². For the coil/auxiliary terminals, the solid wire range is 2x (0.5–1.5 mm²) or 2x (0.75–2.5 mm²). The depth is 140 mm, so plan for that behind the panel door. A 6 mm side clearance is recommended for airflow and tool access.