The Siemens 3RW5517-1HF14 is a soft starter from the SIRIUS family, rated for a supply voltage of 200 to 480 V — covering common global line voltages from 208 V to 480 V without a transformer tap change. Trip Class is selectable: CLASS 10A / 10E (default) / 20E / 30E per IEC 60947-4-2. CLASS 10A is the standard for standard-start motor loads; CLASS 20E or 30E give longer acceleration time for high-inertia loads like centrifuges or large fans. The default 10E is a motor-protection class that matches typical induction motor thermal curves. ATEX and IECEx certification (both Yes) mean this soft starter is approved for use in potentially explosive atmospheres — it can be installed in Zone 2 or Zone 22 areas when paired with an appropriate motor and cabling. The fail-safe input (With Fail-Safe = 1) puts the output into a safe state (open load circuit) on loss of the safety signal, which is required for SIL-rated machine guarding circuits. The B10d value is 1,588,000 cycles. Service Factor is 1.15.
Communication and control integration
This unit supports PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP — four fieldbus protocols on one device, so it fits into Siemens S7, Rockwell ControlLogix, or Modbus-based systems without an external gateway. PROFIenergy is available when used with PROFINET High-Feature communication modules, enabling energy-saving standby modes during production pauses. Analog output is configurable as 4-20 mA (default) or 0-10 V, providing motor current or torque feedback to a PLC or drive controller. Torque Control and Voltage Ramp functions give the commissioning engineer control over starting torque and acceleration profile — useful for soft-starting pumps without water hammer or conveyors without jerk. DC braking is built in, so the soft starter can stop a motor faster than coast-to-rest by injecting DC into the stator — helpful for centrifuges or mixers that need a controlled stop. Pump Ramp Down reduces the deceleration rate for pump applications to avoid pressure surges.
Clearance requirements: 100 mm upwards, 10 mm forwards, 0 mm backwards, 75 mm downwards, and 5 mm at the sides. The backwards clearance of 0 mm means it can be mounted flush against a back panel, saving enclosure depth. Power terminals accept solid conductors: 2x (1.0 to 2.5 mm²) and 2x (2.5 to 10 mm²) — screw terminals (Yes) for secure connections. The wiring practice note: spring-cage terminals on the control side would be typical, but this unit uses screw terminals throughout; torque to manufacturer spec for reliable long-term contact.
The 3RW5517-1HF14 carries CE, UL, and CSA approvals, so it is accepted in European, US, and Canadian installations without additional certification. The approvals list covers the regulatory paperwork for cross-border shipments — think landed, not list: duty and compliance are already handled by these marks.