Soft Starter for Motor Starting Duty
The Siemens 3RW4436-6BC45 is a SIRIUS soft starter rated 281 A at 40 °C, switching motor loads via thyristors on 230 V AC line (50/60 Hz). That 281 A figure at 40 °C is the base rating; derate to 251 A at 50 °C and 217 A at 60 °C, so the mounting position and enclosure ventilation directly govern real-world capacity. Insulation voltage is rated 690 V, and the unit accepts an inside-delta wiring configuration — common for retrofit into existing motor circuits where the contactor and overload are already in place.
Adjustable Current Limitation and Protection
Built-in adjustable current limitation lets you set the starting current between 8% and full load, which helps manage inrush on weak supply networks or mechanically sensitive loads. Motor overload protection and intrinsic device protection are included — the soft starter monitors both the motor and its own thyristor junction temperature, reducing nuisance trips from ambient heat buildup inside a panel. An external reset input and a display for fault signals speed up troubleshooting on the line; the display shows the fault code, not just a single LED.
Mounting and Connection Flexibility
Main circuit connections accept busbar or cable: solid conductors 2x (0.5–2.5 mm²) for auxiliary contacts, and stranded 25–120 mm² for the main power terminals, with a maximum wire length of 500 m from the starter to the motor.
The 3RW4436-6BC45 lifecycle stage is current.