SIRIUS soft starter for motor starting duty
The Siemens 3RW5148-1XC14 is a SIRIUS-brand soft starter rated for a minimum operating current of 240 A at 200-480 V, designed to ramp motors up and down without the mechanical shock of across-the-line starting. It supports trip classes CLASS 10A (default), 10E, and 20E per IEC 60947-4-2, giving you the flexibility to match the thermal protection to the motor's starting profile — CLASS 10A for standard starts, 20E for high-inertia loads that need a longer ramp.
Fieldbus and control integration
Onboard PROFIBUS, Modbus RTU, and PROFINET interfaces let this soft starter drop into most industrial networks without an external gateway — the fieldbus slice is built in, not bolted on. The control circuit uses screw-type terminals, and the unit supports voltage ramp starting (30-100% starting voltage) and soft torque for gentle acceleration of conveyors or pumps. Stopping voltage is fixed at 50%, which means the motor decelerates under controlled torque until the contactor opens — useful for preventing water hammer in pump applications.
Mounting and panel fit
Dimensions are 417 mm high, 210 mm wide, and 203 mm deep — this is a large-frame soft starter that needs a backplate, not a DIN rail. Fastening is by screw fixing, with the mounting surface vertical and rotatable ±90° or tiltable ±22.5° front-to-back. Minimum clearance around the unit: 100 mm above, 75 mm below, 10 mm forward, 5 mm at the sides, and 0 mm backward — plan the enclosure depth and ventilation grilles accordingly to avoid derating.
Environmental and derating considerations
Pollution degree 3 per IEC 60947-4-2 means the unit is suitable for industrial environments with conductive dust or occasional condensation, but not for submersion or heavy washdown. Shock resistance is 15 g / 11 ms, with potential contact lifting above 12 g — relevant if the starter is mounted on a vibrating machine base or near a large contactor bank.
Lifecycle and sourcing posture
No stock-holding claim — lead time and price are per-quote.