The Siemens 3RW4443-6BC44 is a SIRIUS soft starter rated for 352 A at 40 °C, with a 690 V insulation voltage and a 230 V control supply at 50-60 Hz. This is the full-load current capability for a 3-phase induction motor start; the unit can handle 312 A at 50 °C and 270 A at 60 °C, so the operating ambient directly sets the maximum motor FLA you can protect.
Wiring and protection details
Main circuit wiring accepts stranded copper from 70 to 240 mm² (AWG 2/0 to 500 kcmil using both clamping points; 250-500 kcmil via the back point, 3/0-600 kcmil via the front point). Solid wire for auxiliary contacts is 0.5-2.5 mm² (20-14 AWG). Motor overload protection and intrinsic device protection are built in, with adjustable current limitation and an external reset option. The thyristor-based power section supports inside-delta circuit wiring, which reduces the per-phase current seen by the soft starter — useful for retrofitting into existing delta-configured motor windings without over-speccing the unit.
Rated for degree of pollution 3 per IEC 60947-4-2, meaning the environment can have conductive dust or occasional condensation — typical of furnace, mill, or wash-down areas. Storage temperature range is -25 to +80 °C; operating ambient must stay below 60 °C, with derating starting above 40 °C. Maximum motor cable length is 500 m — sufficient for most plant-floor runs. Display version provides fault signal indication on the unit itself, which speeds troubleshooting.