Current derating and thermal budget — the real operating limit
The 3RW4422-1BC44: The derating temperature threshold is 40 °C — above that, the continuous output current drops linearly. For a 45 A motor in a 50 °C panel, this unit holds; for a 50 A motor at 50 °C, you need the next frame up. The integrated bypass contact system carries the full load current after start, pulling the thyristors out of the circuit — this reduces heat buildup in the enclosure and lets the derating curve reflect the bypass contact rating, not the semiconductor junction.
Protection features that reduce external component count
Built-in motor overload protection and intrinsic device protection mean you can omit a separate overload relay in many schemes — the soft starter handles thermal memory and trip class internally. Adjustable current limitation lets you set the start current between the minimum load of 8 % and the unit's full rating, which helps coordinate with upstream breaker settings on high-inertia loads. The inside-delta circuit connection is supported — for six-wire motors, the soft starter connects in the delta leg, reducing the line current to 58 % of the motor FLA. This extends the usable motor size range without stepping up to a larger frame.
Mounting, wiring, and panel fit
Dimensions: 270 mm deep, 170 mm wide, 192 mm high. Screw fixing — mounts on a vertical surface with ±90° rotation and ±22.5° tilt forward/back. Clearance: 100 mm above, 75 mm below, 5 mm at the sides. Main current circuit uses box terminals accepting stranded 2x (4... 50 mm²). Maximum wire length to motor: 500 m.
Environmental and compliance ratings
Pollution degree 3 per IEC 60947-4-2 — suitable for industrial environments where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation is expected. Insulation voltage rated 690 V. Operating temperature during operation: 60 °C; storage range: -25 to +80 °C.