The Siemens 3RT1025-3BG40 is a SIRIUS power contactor in the Size S0 frame, rated for 7.5 kW motor switching at AC-2 duty on 400 V three-phase. That AC-2 rating covers wound-rotor motors or loads with moderate inrush — the contactor sees the full start current but doesn't have to break it under stall conditions. For plugging or inching duty (AC-4), it's rated 15.5 A at 400 V. Main circuit terminals are screw-type, accepting 2x (1 to 2.5 mm²) solid or stranded, or up to 2x 10 mm². The front face carries IP20 finger protection; the terminal body itself is IP00, so keep live parts inside the enclosure.
Environmental and coordination
The coil draws 5.4 W both on pick-up and hold — DC-operated, so no AC hum and consistent power draw.