Siemens 3RT1025-1BB4 Contactor

Siemens Sirius 3RT1025-1BB4 Contactor is a three‑pole power contactor with a 24 V DC coil (size S0) designed to start and stop three‑phase motors in AC‑3 duty. It provides three normally open main contacts (0 NC) and wires the main circuit via screw terminals for reliable panel wiring; the unit is rated for 400 V AC up to 17 A, which corresponds to about 7.5 kW motor control at 400 V. The device features front IP20 protection and is intended for panel mounting in control cabinets. The 3RT1025 family specifies a -25 to +60 °C ambient operating range, and a mechanical life of up to 10,000,000 cycles, with substantial electrical durability for repeated switching. It is UL listed (UL File E31519) and Siemens notes that the successor for this model is 3RT2025-1BB40, providing a clear upgrade path. This compact 3‑pole contactor of the Sirius 3RT line is commonly used in industrial automation to control motors and other inductive loads, offering a straightforward 24 V DC coil, screw-terminal wiring, and a robust S0 frame suitable for control panels and enclosures.