Rated current and thermal derating — the real ceiling for motor starting
The 3RW4027-1BB15: For a continuous-duty motor start application, the actual load current must stay below the derated value at the enclosure ambient — if the panel runs at 50 °C, budget 29 A max, not the 40 °C headline. Minimum load is 20 % of the rated current — below that the soft starter may not reliably detect the motor. Don't oversize the unit for a lightly loaded motor; match the frame to the motor FLA within the 20–100 % window.
Integrated bypass — one less contactor to wire
The integrated bypass contact system eliminates the external bypass contactor and its control wiring. That saves a DIN slot and reduces the bill of materials — the soft starter handles the start ramp, then the internal bypass shorts the thyristors for run mode, dropping heat dissipation. Size S0 frame (45 mm wide, 125 mm high, 155 mm deep) mounts on standard 35 mm DIN rail or screws directly to the panel backplate. The screw-and-snap-on fastening lets you pre-wire the panel and snap the unit in last.
Control voltage and field wiring — global panel fit
Control supply accepts 110–230 V DC, covering the common DC bus voltages in industrial panels. Insulation voltage is 600 V, pollution degree 3 per IEC 60947-4-2 — no derating needed in dusty industrial environments. Operating temperature range -25 to +60 °C covers most indoor panels without forced cooling.