Motor starting with integrated bypass
The 3RW4434-6BC34: The integrated bypass contact system switches the thyristors out of the circuit once the motor is at speed, eliminating semiconductor heat losses during continuous run — the bypass carries the full motor current, not the silicon.
Current derating and thermal planning
If the panel ambient runs above 40 °C — common in a crowded enclosure with drives and contactors — the soft starter's continuous current capacity drops. The derating temperature is listed at 40 °C, so the panel ventilation and mounting position (vertical surface, ±90° rotatable, ±22.5° tiltable per) directly affect whether the unit can deliver its full rating. Adjustable current limitation lets you set the starting torque profile between 8% minimum load and the full rated current.
Wiring and connection sizing
Main circuit connections accept busbar or cable: stranded 25–120 mm², finely stranded 16–95 mm², or AWG 4–250 kcmil. The front and back clamping points both take 6–2/0 AWG; using both clamping points maxes at 2x 1/0. Maximum motor cable length is 500 m — beyond that, capacitive charging current from the cable can interfere with the soft starter's firing circuit. For long cable runs between the starter and motor, keep the total under this limit or add a line reactor.
Inside-delta wiring option
Inside-delta circuit capability means the soft starter can be wired between the motor windings rather than in the supply lines. This reduces the current through each thyristor to 58% of the line current — a 196 A line-rated starter in inside-delta configuration handles a motor with 338 A FLA. Useful for larger motors where the starter frame size would otherwise jump to the next rating.