Rated current and thermal derating
The 3RW4455-2BC35 delivers 1200 A at 40 °C ambient — this is the base rating for sizing the motor branch circuit. The derating temperature threshold is 40 °C; above that the thyristor junction temperature limits the output. For a pump or conveyor pulling 1000 A FLA in a 50 °C panel, this unit still has headroom — but at 60 °C the margin narrows to 46 A below the 1000 A mark.
Integrated bypass and inside-delta wiring
The integrated bypass contact system shorts the thyristors after the motor reaches full speed, eliminating SCR conduction losses during run. This means the heat sink sees only the start transient, not the full-load continuous dissipation — a meaningful advantage for panel fill factor and ventilation design. Inside-delta circuit capability allows the soft starter to be wired in the motor delta loop rather than the supply line, reducing the current through each SCR leg by roughly 42% compared to standard in-line connection. This is the wiring topology to use when the motor is delta-connected and the starter is sized for the phase current, not the line current.
Mounting dimensions and panel layout
Mounting position allows a vertical surface with +/-90° rotation and +/-22.5° tilt forward/back. Clearance requirements: 100 mm upward, 75 mm downward, 5 mm at the sides — the side gap is tight, so adjacent components must not block airflow across the heatsink fins.
Termination and wiring
Main current circuit termination is busbar connection — expect flat copper bars, not cable lugs, for the 1200 A path. The stranded wire range for the main circuit is 70–240 mm², finely stranded 50–240 mm², and AWG/kcmil 2/0–500.
Protection and control features
Motor overload protection and intrinsic device protection are built in — no separate overload relay needed in the motor branch circuit. Adjustable current limitation lets the starting current be set between 8% and 100% of the rated current, with a minimum load threshold of 8% below which the starter may not reliably detect the motor. A display for fault signals and external reset capability simplify troubleshooting on the line. The unit also includes a motor brake output component for applications requiring DC injection braking at stop.
Lifecycle and sourcing
For volume commitments or scheduled builds, confirm lead time and MOQ at quote.