Rated for the heavy lift — 1524 A at 40 °C
The Siemens SIRIUS 3RW4457-6BC45 is a soft starter rated 1524 A at 40 °C, derating to 1351 A at 50 °C and 1200 A at 60 °C. That 1524 A figure governs the full-load motor current it can start and run through the thyristor stack — sized for large induction motors on 400 V to 690 V lines. The 690 V rated insulation voltage and pollution degree 3 per IEC 60947-4-2 mean it's built for industrial panels where conductive dust or humidity is present; no need to overspec for dirty environments. Inside-delta wiring is supported, which lets the starter control only two phases while the motor's own windings complete the third.
Integrated bypass — no external contactor needed
An integrated bypass contact system bridges the thyristors after start, so the soft starter runs cool in continuous operation and the bypass carries the full motor current without thyristor losses. No separate bypass contactor to wire, size, or fail. The unit also includes motor overload protection and intrinsic device protection, covering both the motor and the starter's own semiconductors against overtemperature and overcurrent. Mounting is screw fixing to a vertical surface, rotatable ±90° and tiltable ±22.5° front-to-back. Clearances: 100 mm above, 75 mm below, 5 mm at the sides. The 640 mm height and 510 mm width need a substantial enclosure.