The Siemens SIRIUS 3RW3016-1BB14 is a size S00 soft starter rated 9 A at 40 °C, built for controlled motor starting in a 45 mm wide DIN-rail footprint. It carries an integrated bypass contact system, so once the motor is up to speed the thyristors are shorted out — no continuous heat dissipation from the power stack during run. That keeps the panel cool and extends the life of the surrounding components in a crowded enclosure.
Clearance requirements: 60 mm upwards, 40 mm downwards, 15 mm at the side. The screw-type terminals on the main circuit and the auxiliary/control circuit accept 2x (0.25 to 2.5 mm²) solid conductors, with the front clamping point taking 2x (16 to 10) AWG. Wire length to the motor can run up to 300 m — fine for most pump and conveyor layouts on a mill floor.
This is a soft starter, not a contactor — the thyristor ramp limits inrush current and mechanical shock on the load. The integrated bypass is the key differentiator from a basic starter: once the motor is at speed, the bypass contactor carries the full-load current, so the thyristors cool off. No separate bypass contactor to wire in the panel. The control supply accepts 110 to 230 V DC, which is wider than the typical 24 V DC on smaller SIRIUS soft starters, so it can share a control transformer with other 120 V or 220 V DC loads without a separate power supply.
Derating is straightforward: 9 A at 40 °C, 8 A at 50 °C, 7 A at 60 °C. The minimum load is 10 % of the rated current, so it will not drop out on a lightly loaded motor. No motor overload protection built in — that needs to come from a separate overload relay or the drive's own thermal model. No adjustable current limitation, no inside-delta circuit, no external reset, no motor brake output. The red fault signal on the display gives a visual trip indication without needing to open the panel door.