The Siemens 3RW4454-6BC46 is a SIRIUS soft starter for three-phase induction motors, rated 1065 A at 40 °C and 690 V insulation voltage, operating at 50/60 Hz. It uses thyristor-based current limitation with an adjustable setting down to 8% minimum load, and includes an integrated bypass contact system that removes the thyristors from the circuit once the motor is at speed — reducing heat dissipation and extending service life in continuous-run applications like pumps or conveyors.
The 690 V insulation voltage (rated impulse withstand per IEC 60947-4-2) covers 400 V and 480 V systems comfortably, but check your line-to-line peak if running on a 690 V network. Inside-delta wiring is supported, meaning the soft starter can be connected in the motor's delta legs rather than in the supply lines. This reduces the current through the thyristors to 58% of the motor FLC — effectively allowing a smaller unit to start a larger motor. If your motor is delta-connected and you have access to the six leads, this is a cost-saving configuration.
Main circuit connection is via busbar; the unit accepts stranded cable 70–240 mm² and finely stranded 50–240 mm², or 2/0–500 kcmil for imperial systems. Auxiliary and control circuits use screw terminals accepting 0.5–2.5 mm² solid or 20–14 AWG. Maximum motor cable length is 500 m — adequate for most industrial runs, but check for voltage drop on long feeders.