Motor switching for the panel line
The Siemens 3RT1025-1AL25 is a Size S0 contactor from the SIRIUS family, rated for AC-3 duty at 7.5 kW at 400 V. That AC-3 rating means it's built for switching three-phase induction motors — the 7.5 kW figure covers common pump, fan, and conveyor motors up to that load. The 230 V AC coil at 50/60 Hz is standard for European control circuits; verify your control transformer taps before wiring. Three main poles handle the motor circuit, and the built-in 1 NO + 1 NC auxiliary contact block gives you one feedback signal and one interlock without adding a separate module. Screw terminals on Size S0 make it a direct swap into existing panels where spring-cage hasn't been adopted yet.
DIN-rail integration note
Size S0 snaps onto standard 35 mm DIN rail per EN 60715. The screw terminals accept up to 4 mm² stranded or 6 mm² solid — torque to 1.2 Nm for the power terminals, 0.8 Nm for the auxiliaries. Leave a 10 mm gap above and below for air circulation if the panel is enclosed.