ATEX-rated soft starter for hazardous-area motor starting
The Siemens 3RW5072-6TB05 is a soft starter with ATEX and IECEx certification, meaning it can be installed in explosive atmospheres where standard starters cannot go. This is the headline differentiator for this unit — most soft starters in this current class lack hazardous-area approvals. Rated for a minimum operating current of 90 A and a supply voltage range of 200 to 600 V, it covers the common low-voltage motor networks across Europe, North America, and Asia. The trip class is selectable between CLASS 10A, 10E (preset), and 20E per IEC 60947-4-2, which directly governs how quickly the starter disconnects during a locked-rotor event.
Fieldbus and control features for integrated motor management
Built-in PROFINET standard, PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP support means this starter talks directly to the PLC without an external gateway. The PROFINET interface also supports PROFIenergy for coordinated energy management during idle periods. Soft torque, voltage ramp, and pump ramp down are all standard — these reduce mechanical shock on conveyors, pumps, and compressors during start and stop. The auto-reset and remote reset (by cycling the 24 V control supply) allow unattended restart after a fault, which is useful for remote or unmanned installations. Mounting is screw-fix with a vertical mounting surface that can be rotated ±90° or tilted ±22.5° front-to-back. Clearance requirements: 100 mm upwards, 75 mm downwards, 10 mm forwards, 0 mm backwards, 5 mm at the sides — plan the panel gland plate and cable entry accordingly.
Approvals and compliance for global installations
UL and CSA approvals cover North American panel builds; CE marking covers the European market. The ATEX and IECEx certifications are the key differentiator — this unit is suitable for Zone 1 or Zone 2 gas and dust atmospheres where a standard soft starter would require an expensive purge system. Shock resistance is 15 g / 11 ms, dropping to 12 g / 11 ms with potential contact lifting. Physical footprint: 160 mm wide, 230 mm high, 282 mm deep. The service factor is 1, meaning no built-in overload margin — the trip class settings handle the motor protection.