352 A at 40 °C — the rating that sizes the motor branch
The 3RW4443-2BC36 is a Siemens SIRIUS soft starter rated 352 A at 40 °C ambient, which means it handles a motor full-load current up to that figure in a standard 40 °C panel environment. Insulation voltage is 690 V, so it sits comfortably on 400 V or 480 V systems with headroom for transient spikes. The minimum load is 8 % of rated current — it won't drop out on lightly loaded conveyors or pumps that draw well below the starter's full-scale rating.
Inside-delta wiring and adjustable current limit
This soft starter supports inside-delta circuit connection, which places the thyristors in the motor windings rather than the line. That reduces the line current draw by roughly 42 % compared to standard in-line connection — a 352 A inside-delta unit handles the same motor as a 600 A in-line unit, saving panel space and copper. The adjustable current limitation lets you set the starting torque ceiling between 8 % and 100 % of the motor FLA without swapping hardware. For a pump start that needs 60 % torque to avoid water hammer, dial it in on the display — no parameter software required.
Mounting and panel integration — screw fixing, not DIN rail
Mounting is by screw fixing, not DIN-rail snap-on — the panel backplate needs drilled and tapped holes. The unit is 230 mm high, 210 mm wide, and 298 mm deep, so budget that depth clearance behind the panel door, plus 100 mm upwards and 75 mm downwards for cable bending radius. Main circuit connection uses busbar or cable lugs — stranded 70 to 240 mm² or 2/0 to 500 kcmil. The mounting position allows ±90° rotation and ±22.5° tilt forward/backward, so it fits odd-angle enclosures.
Active production — sourced through the franchise
The SIRIUS brand means full factory traceability, Siemens warranty, and compliance documentation (CE, UKCA, EAC) included with the shipment. No gray-market risk on the thyristor modules or control board.