160 A soft starter with ATEX certification for hazardous zones
The Siemens 3RW5075-2AB04 is a hybrid switching device rated for a minimum of 160 A, operating across 200-480 V. It carries ATEX, UKEX, and IECEx certification, meaning it can be installed in explosive atmospheres (gas or dust) without an additional isolation barrier — the soft starter itself is the Ex-rated component. Trip class is selectable between CLASS 10A, 10E (preset), or 20E per IEC 60947-4-2. The unit measures 282 mm deep, 160 mm wide, and 230 mm high, with screw fixing to the mounting surface. Mounting position is flexible — vertical surface with ±90° rotation and ±22.5° tilt front-to-back — which helps when retrofitting into existing enclosures where the old starter's footprint doesn't match.
Fieldbus and control integration
Communication options cover PROFIBUS, PROFINET (with PROFIenergy support via the standard communication module), Modbus RTU, Modbus TCP, and EtherNet/IP. This makes the 3RW5075-2AB04 a drop-in for most plant-floor networks without a protocol gateway — the soft starter speaks the line's native fieldbus. An analog output is configurable as 4-20 mA (default) or 0-10 V (parameterizable with the High Feature HMI). This gives the PLC or DCS a direct current or voltage signal proportional to motor current, useful for trending load changes on pumps or conveyors without a separate CT. Auto-reset and remote reset (by cycling the control supply voltage) are both supported, reducing the need for a manual reset button at the panel when the starter trips on overload. The error logbook feature is available only with special accessories.
Starting profiles for mechanical and electrical stress reduction
Voltage ramp and soft torque are both available. Voltage ramp gradually increases motor voltage over an adjustable period, limiting inrush current to typically 300-400% of FLA instead of the 600-800% seen with direct-on-line starts. Soft torque further shapes the initial torque ramp to reduce mechanical shock on gearboxes and belt drives. Pump ramp down is included — a controlled deceleration profile that reduces the motor voltage gradually during stop, minimising fluid hammer in piping systems. This is a standard feature, not an option card. Minimum load is 15% relative to the smallest settable Ie, meaning the soft starter can handle lightly loaded motors without dropping out of regulation. The service factor is 1, so continuous operation at rated current is the design limit — no built-in overload margin.
Environmental and compliance documentation
The unit withstands 15 g / 11 ms shock (12 g / 11 ms with potential contact lifting). Clearance distances: 100 mm upwards, 10 mm forwards, 75 mm downwards, 5 mm at the sides. ATEX, UKEX, and IECEx certification means the unit is suitable for Zone 1/21 or Zone 2/22 hazardous areas per the applicable equipment group — the exact zone classification depends on the gas/dust group and temperature class of the installation.
For panel builders or MRO buyers: the screw-fixing mount and flexible orientation mean it can replace an older soft starter in the same enclosure without drilling new holes, provided the 282×160×230 mm envelope fits. Confirm the control voltage and fieldbus protocol match your existing network before committing the BOM line.