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.
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 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.