The Siemens 3RT2025-1HA40 is a 3-pole power contactor in the SIRIUS family, frame size S0. Its AC-3e/AC-3 rating of 17 A and 7.5 kW at 400 V means it is sized for switching three-phase induction motors up to that load — common for small pumps, fans, and conveyors in a control panel. The 12 V DC coil with a 0.7–1.25× Uc operating range holds in reliably on a nominal 12 VDC supply; dropout is clean below the lower threshold, so no chattering on a sagging bus.
Screw terminals accept up to the rated wire size — no special tooling needed for panel wiring. The contactor includes 1 NO + 1 NC auxiliary contacts built in, and the datasheet confirms no additional auxiliary switch block can be added, so the onboard set is your full aux capacity. Plan your feedback and status signals accordingly.