Rated current and thermal derating
The 3RW4427-1BC34: At a 40 °C ambient the soft starter delivers 161 A continuous. That drops to 142 A at 50 °C and to 125 A at 60 °C — the derating curve matters when the starter sits in a crowded panel or near a heat source. The derating temperature is 40 °C, meaning the full 161 A rating holds only up to that ambient; above it you must reduce the load current per the published curve.
Integrated bypass and inside-delta wiring
An integrated bypass contact system means the thyristors are shorted out once the motor reaches full speed, eliminating SCR conduction losses during run time and reducing heat in the enclosure. Inside-delta circuit capability allows the starter to be wired in the motor delta connection — this reduces the current through the starter to 58% of the line current, effectively extending the current range of the unit for a given motor.
Adjustable current limit and minimum load
The adjustable current limitation lets you set a peak current ceiling during start, protecting both the motor and the supply from high inrush. The minimum load is 8% of the rated current, so the starter can handle lightly loaded motors without tripping or misfiring.
Panel fit and wiring terminals
Dimensions are 170 mm wide, 192 mm high, and 270 mm deep. Screw fixing with a vertical mounting surface — the enclosure can be rotated ±90° or tilted ±22.5° front-to-back, giving flexibility in tight cabinets. The box terminal design on the main circuit provides a reliable, high-torque connection.