What this soft starter delivers
The 3RW4454-2BC45: It carries a 690 V rated insulation voltage (IEC 60947-4-2) and operates on 50/60 Hz mains at 230 V coil/control voltage. The integrated bypass contact system drops the thyristors out of the circuit after start, cutting heat dissipation in the cabinet for continuous running. An inside-delta circuit configuration is supported, which reduces the current seen by the soft starter to 58% of the motor FLA — useful for large motors where the starter frame size would otherwise jump a bracket.
Protection and control features
Built-in motor overload protection (class 10/20/30 adjustable) and intrinsic device protection mean the starter monitors its own thyristor junction temperature — no separate overload relay needed for the power section. Adjustable current limitation (8% minimum load) lets you set the start current between 2x and 5x FLA depending on the application. The external reset input allows remote fault clearing from a PLC or pushbutton station. A built-in display shows fault codes and operating status — no external HMI required for basic diagnostics. The unit also includes a motor brake output for applications needing DC injection braking.
Mounting, wiring, and environment
Dimensions are 640 mm high, 510 mm wide, 290 mm deep — this is a large-frame unit that needs a dedicated backplate section. Fastening is by screw fixing; the mounting position allows vertical surface with +/-90° rotation and +/-22.5° tilt forward/back. Main circuit connections are busbar, rated for 70–240 mm² stranded or 2/0–500 kcmil. Pollution degree 3 per IEC 60947-4-2 means it's rated for industrial atmospheres with conductive dust or condensation. Ambient operating range is 60 °C max; storage range is -25 to +80 °C. Clearance requirements: 100 mm above, 75 mm below, 5 mm at the sides.
Sourced through authorized Siemens distribution channels. The maximum motor cable length is 500 m — plan for voltage drop on long runs.