Soft Starter for ATEX-Rated Motor Circuits
The Siemens 3RW5517-3HF14 is a SIRIUS soft starter carrying ATEX and IECEx certification, per the specification, making it suitable for starting and protecting motors in potentially explosive atmospheres (zones where ATEX-directive apparatus is required). Rated for a supply voltage of 200 to 480 V (50/60 Hz), it integrates PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP on the communication side, so it fits into most common fieldbus architectures without an external gateway. The unit provides DC braking, voltage ramp, pump ramp down, and torque control, which gives the commissioning engineer flexibility for different load types — pumps, conveyors, or fans — without adding external control modules.
Dimensions and Mounting Clearances
The enclosure measures 275 mm high by 170 mm wide by 152 mm deep, per the datasheet dimensions. Required clearances for heat dissipation: 100 mm upwards, 75 mm downwards, 10 mm forwards, 0 mm backwards, and 5 mm at the side — these must be maintained in the panel layout to keep the unit within its thermal design.
Protection and Trip Characteristics
Trip Class is selectable: CLASS 10A / 10E (default) / 20E / 30E, according to IEC 60947-4-2, which governs the maximum allowable stall time before the soft starter trips — CLASS 10 is standard for standard-start induction motors, while CLASS 20 or 30 accommodates high-inertia loads. Accuracy Class 5 per IEC 61557-12 applies to the integrated motor protection functions, meaning the current measurement error stays within ±5 % of the reading — adequate for overload protection in most industrial applications. A service factor of 1.15 is supported, so the soft starter can be set to allow continuous overload up to 115 % of the motor FLA without tripping, matching typical NEMA motor service factors.
I/O and Control Functions
An analog output is configurable as 4-20 mA (default) or 0-10 V, providing a real-time signal proportional to motor current or other parameters for a PLC or remote indicator. The unit includes a fail-safe input (with fail-safe 1), an event list, error logbook, trace function, and motor heating function — the latter keeps the motor warm in standstill to prevent condensation in humid environments. Remote reset and auto-reset are both available, allowing the soft starter to recover automatically after a fault clears, which is useful for unattended installations.
The 3RW5517-3HF14 is an active Siemens SIRIUS product line item. For audit purposes, the CE, UL, and CSA markings are confirmed on the datasheet, covering European, US, and Canadian regulatory jurisdictions.