Rated current and thermal derating — the real-world continuous duty ceiling
The 3RW4456-2BC44 is rated 1351 A at 40 °C, 1200 A at 50 °C, and 1065 A at 60 °C. That 21 % drop from 40 °C to 60 °C is the derating curve you need for the enclosure ambient — if the panel hits 50 °C, the continuous current ceiling is 1200 A, not the headline 1351 A. This is a SIRIUS soft starter with an integrated bypass contact system, meaning after the start ramp the thyristors are shorted and the motor runs through the bypass contacts — heat dissipation drops to near-zero during run, so the derating matters mainly for repeated start cycles or stalled-rotor conditions.
Protection architecture — three functions in one device
Motor overload protection, intrinsic device protection (thyristor overtemperature, phase imbalance, SCR short-circuit detection), and adjustable current limitation are all onboard. That eliminates the separate overload relay and reduces panel wiring — the soft starter manages the motor thermal model directly. The minimum load setting is 8 % of the rated current, so it can start lightly loaded conveyors or pumps without nuisance tripping on the current-limitation threshold.
Inside-delta wiring and motor brake output — two architecture choices that affect panel layout
Inside-delta circuit wiring is supported — this connects the soft starter in the delta legs of a six-lead motor, reducing the current through the thyristors by a factor of √3 compared to inline wiring. For a given motor power, the inside-delta configuration lets you use a smaller-frame soft starter. A motor brake output is integrated, so for applications with a mechanical holding brake (vertical conveyors, hoists), you skip the separate brake contactor and its control wiring.
Termination split — main circuit busbar, control circuit spring-clamp
The main current circuit terminates via busbar connection — stranded 70...240 mm² or finely stranded 50...240 mm², with AWG 2/0...500 kcmil also listed. That split means the power cables land on busbars (torque-controlled, typically M10 or M12 studs), while the control wiring pushes into spring-clamp terminals — no screwdriver needed for the control side, which speeds up commissioning.
Mounting and environmental envelope
The unit measures 640 mm high by 510 mm wide by 290 mm deep, fastened by screw fixing. Mounting position allows a vertical surface with ±90° rotation and ±22.5° tilt forward/backward — useful when the panel layout forces an off-axis orientation. Pollution degree 3 per IEC 60947-4-2 means it tolerates conductive dust and occasional condensation — standard for industrial enclosures without climate control. Storage temperature range is -25 to +80 °C; operation up to 60 °C ambient. Clearance requirements: 100 mm upwards, 75 mm downwards, 5 mm at the sides. The 500 m maximum wire length from the soft starter to the motor limits voltage drop on long cable runs — factor this into the motor circuit layout.
Sourced through independent distribution channels. No stock-holding claim; quoted per RFQ.