The Siemens SIRIUS 3RT1025-1AP00-ZX95 is a size S0 power contactor with three normally-open main contacts, screw-type terminals, and a footprint that fits a 45 mm DIN-rail slot. It is rated for AC-4 switching duty at 400 V up to 15.5 A, which covers reversing and plugging applications on motor loads where the contactor makes and breaks the current under load.
Mounting and integration
Mounts via screw or snap-on onto a 35 mm standard mounting rail per DIN EN 50022. The 45 mm width and 85 mm height leave room for auxiliary contact blocks on the side; a 6 mm clearance to adjacent devices is specified for side-by-side mounting. The front face carries an IP20 rating; the terminal area is IP00, so the panel enclosure must provide the overall environmental seal.
Ratings and what they mean for the panel
The AC-4 rating of 15.5 A at 400 V is the figure that governs motor reversing or inching duty — the contactor must break the locked-rotor current each cycle. For less demanding AC-3 (starting/running) duty, the contactor can handle higher currents; the AC-2 rating at 400 V is 7.5 kW, typical for slip-ring motor switching. The AC-12 rating of 10 A covers resistive loads like control transformers. Pollution degree 3 means the contactor is suited for industrial environments with conductive pollution, common in panel builds.