Explosive atmosphere certified — ATEX, UKEX, IECEx
The 3RW5072-6TB15: This soft starter carries ATEX, UKEX, and IECEx certification, meaning it is approved for installation in potentially explosive gas or dust atmospheres per the respective directives. For a chemical or petrochemical line handling volatile solvents, that certification is the gatekeeper — without it the starter cannot sit in the classified zone.
Rated current, voltage, and trip class — what drives fit
The minimum set current is 90 A, with a rated operating voltage range of 200 to 600 V. That 90 A floor means this unit is sized for motors drawing at least that much full-load current — a 45 kW motor at 400 V typically pulls around 85 A, so the 90 A minimum catches that class of load without needing to oversize the starter. Trip class is selectable between CLASS 10A, 10E (preset), and 20E per IEC 60947-4-2.
Fieldbus connectivity — PROFIBUS, Modbus RTU/TCP, EtherNet/IP
Onboard PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP mean this starter drops into most common control networks without an external gateway. PROFIBUS DP is still the backbone in many European process plants; EtherNet/IP covers the North American machine-build standard. Modbus TCP is the fallback for legacy SCADA integration. PROFIenergy is supported via the PROFINET communication module — that allows the drive to report energy consumption data and participate in coordinated load-shedding during production pauses. Useful if the plant runs an energy management system that expects PROFIenergy telegrams.
Soft start features — voltage ramp, soft torque, pump ramp down
Voltage ramp and soft torque give you two ways to manage the motor acceleration profile. Voltage ramp applies a linear voltage rise from an initial level to full voltage — straightforward for conveyors and compressors. Soft torque is a current-limiting start that holds the torque below a set ceiling, useful for loads that cannot tolerate a high breakaway torque spike. Pump ramp down is a controlled deceleration that reduces the voltage gradually to avoid water hammer in pumping systems. Without it, a pump stopping under full voltage can slam the check valve and burst a pipe joint. The feature is standard on this unit — no extra option card needed.
Operating temperature and derating — what the numbers mean
That means at 50 °C ambient in a crowded panel, the continuous current rating must be reduced — typically by 2-3 % per degree above 40 °C, though the exact curve is in the product manual. If the panel ambient is 55 °C and the motor draws 90 A, this starter may need to be oversized one frame to stay within the derated limit.