954 A at 40 °C — derating curve matters for the panel build
The 3RW4453-2BC45: That derating slope means the panel ventilation and mounting position directly set the usable current — screw-fixed to a vertical surface, rotatable ±90° and tiltable ±22.5°, so you can orient it to pull cooler air across the heatsink. Insulation voltage rated 690 V, pollution degree 3 per IEC 60947-4-2, so it handles the typical 400–690 V industrial mains with margin for transient overvoltage in dirty environments.
Integrated bypass and inside-delta wiring
Built-in bypass contact system means the thyristors are shorted out once the motor is up to speed — no external bypass contactor needed, and the heat load in the panel drops to near zero during run. The inside-delta circuit option lets you wire the soft starter between the motor windings instead of in-line, reducing the current the unit sees by a factor of √3; useful for retrofitting into existing motor terminal boxes where cable routing is tight. Adjustable current limitation from 8% minimum load lets you dial in the start current to match the supply transformer capacity or generator set — set it just above the motor's no-load magnetizing current and the ramp is smooth without tripping upstream breakers.
Motor overload and intrinsic device protection onboard
Motor overload protection is integrated — no separate overload relay needed for the soft starter branch circuit. Intrinsic device protection monitors the thyristor junction temperature and shuts down before the semiconductor exceeds its SOA, which is the failure mode that takes out un-protected soft starters on a stalled-rotor start. External reset input and a display for fault signals mean the maintenance team gets a readable fault code without plugging in a laptop. The motor brake output component is built in, so a DC injection brake can be wired directly without an extra contactor.
Termination and wire sizing for the main circuit
Main current circuit termination is busbar connection — no lugs to crimp, just bolt the busbar directly. The stranded wire range is 70–240 mm², finely stranded 50–240 mm², and for North American builds it accepts 2/0–500 kcmil. Physical footprint: 510 mm wide, 640 mm high, 290 mm deep. Clearance requirements: 100 mm above, 75 mm below, 5 mm at the sides. Maximum motor cable length is 500 m — beyond that the cable capacitance can cause nuisance thyristor firing from leakage current.