Hazardous-area soft starter — ATEX and IECEx on the nameplate
This Siemens 3RW5525-1HA04 carries both ATEX and IECEx certification, so it can be installed in Zone 1 or Zone 2 gas-group environments without an external isolation barrier for the starter itself — the nameplate is the permit. The rated voltage range is 200 to 480 V, covering common 230 V and 400 V three-phase networks across Europe and North America without a transformer tap change.
Trip-class flexibility — 10A, 10E, 20E, or 30E per IEC 60947-4-2
The 3RW5525-1HA04 supports four trip classes: CLASS 10A, 10E (default), 20E, and 30E, all per IEC 60947-4-2. This means you can match the thermal overload protection to the motor's startup profile — CLASS 10 for standard-start loads like pumps and fans, CLASS 20 or 30 for high-inertia loads such as centrifuges or crushers where the start time exceeds 10 seconds. The default trip class is 10E, which provides a 10-second thermal limit at 7.2× rated current — adequate for most constant-torque applications. Switching to CLASS 30E extends the limit to 30 seconds, useful when the driven load needs a longer acceleration ramp.
Fieldbus and I/O — Modbus RTU, Modbus TCP, EtherNet/IP, and analog output
The soft starter ships with native support for Modbus RTU (RS-485), Modbus TCP, and EtherNet/IP, so it drops into most plant-floor networks without a separate gateway module. PROFIBUS and PROFINET are also listed as supported. An analog output is configurable as 4–20 mA (default) or 0–10 V, letting you feed motor current or torque feedback directly to a PLC analog input or a local panel meter without an external signal conditioner. The unit includes a voltage ramp start, pump ramp-down, breakaway pulse, and torque control — all parameterizable via the four digital inputs or the fieldbus interface.
Thermal environment — operating range and derating above 40 °C
In a non-ventilated enclosure at 50 °C, expect to reduce the continuous rated current by the factor given in the manual — typically 2–3 % per degree above 40 °C. Clearance requirements: 100 mm above, 75 mm below, 10 mm forward, 5 mm sideways — plan the DIN-rail layout so the hot air rising from the heatsink can escape without recirculating into the intake.
Compliance and approvals — UL, CSA, CE, ATEX, IECEx
The soft starter carries UL, CSA, and CE marking, so it is accepted for panel builds shipped to North America and the European Economic Area without additional certification delays. ATEX and IECEx certification (both listed) means the unit is suitable for potentially explosive atmospheres per the ATEX 2014/34/EU directive and the IECEx scheme — the nameplate carries the marking, and the declaration of conformity is available from Siemens.