230 A at 40 °C — derating drives the real current budget
The 3RW4073-2BB45: This is the headline current, but the real budget is set by the ambient: at 50 °C the unit delivers 205 A, and at 60 °C it drops to 180 A. If your enclosure runs hot near the furnace line, plan on the 180 A ceiling — the 230 A figure assumes a 40 °C environment with no derating. Size S12 frame, 230 mm high, 160 mm wide, 278 mm deep — screw fixing to the back panel. The depth matters for gland-plate clearance; allow the full 278 mm plus the 100 mm upward and 75 mm downward clearance for ventilation and cable bending radius.
Pollution degree 3 and mounting position flexibility
The soft starter handles it without conformal coating on the power board, but the cabinet should maintain basic filtration. Mounting position is flexible: with the additional fan fitted, the unit can be mounted on a vertical surface and rotated ±90° or tilted ±22.5° front-to-back. Without the fan, the tilt range narrows to ±10°. This matters when shoehorning the S12 frame into a tight MCC bucket or a retrofit panel.
Motor protection and adjustable current limitation
Built-in motor overload protection and intrinsic device protection mean the 3RW4073-2BB45 can serve as the sole overload element in the motor branch circuit, provided the downstream contactor and overload relay coordination is respected. The adjustable current limitation lets you set the starting current between 20% and 100% of the rated current — useful for soft-starting conveyors or pumps without mechanical shock. The unit is not configured for inside-delta wiring — it is a standard in-line soft starter. The main circuit connection uses busbar or cable lugs: the back clamping point accepts 250–500 kcmil, the front clamping point 3/0–600 kcmil, and both clamping points together can take 2/0–500 kcmil per side. Wire length to the motor is limited to 300 m maximum.