What this soft starter delivers for a 100 A motor line
The 3RW5073-6AB05 is a Siemens SIRIUS soft starter rated for a minimum 100 A motor load, with a voltage range of 200 to 600 V covering most global low-voltage supplies. ATEX and IECEx certification (both marked Yes) means this unit can be installed in Zone 2 or Zone 22 hazardous areas without an external safety barrier, provided the downstream motor and cabling also carry the same rating. That alone saves a panel redesign when retrofitting into an existing classified area.
Mounting and panel fit — screw fixing, clearances, and orientation
Mounting is by screw fixing, not DIN rail snap-on, so budget for four M6 screws into a backplate. The dimensions are 230 mm high, 160 mm wide, 282 mm deep — that's a substantial footprint; plan for a 300 mm deep enclosure minimum to leave room for cable bending radius at the top and bottom. Clearance requirements are tight: 100 mm upwards, 75 mm downwards, 10 mm forwards, 5 mm at the sides, and 0 mm backwards. The vertical mounting surface can be rotated ±90° or tilted ±22.5° forward/back, giving flexibility to fit into odd-shaped panels without a custom bracket.
Communication and control — fieldbus options and remote reset
This soft starter supports PROFIBUS, PROFINET standard, Modbus RTU, Modbus TCP, and EtherNet/IP. That's the full modern fieldbus suite — no need for a separate gateway if your plant runs on any of these. PROFIenergy is available when paired with the PROFINET communication module, which lets the drive participate in energy management during idle periods. Remote reset is achieved by cycling the 24 V DC control supply voltage. Auto-reset is also available, so a line-down fault can be cleared remotely without a site visit — useful for remote pumping stations or conveyor lines. An analog output provides 4-20 mA (default) or 0-10 V (parameterizable with the High Feature HMI) for feeding motor current or load status to a PLC or local meter.
Starting methods and load-specific features
Voltage ramp and soft torque are both supported, giving two distinct starting profiles: voltage ramp for general-purpose loads, soft torque for conveyors or mixers where a hard start would shift product. Pump ramp down is also present — this extends the deceleration time to prevent hydraulic shock in pump applications, a common cause of pipe joint failures. The minimum load is 15% of the smallest settable Ie, so it can handle lightly loaded motors without dropping out or nuisance tripping. Service factor is 1, meaning no continuous overload margin beyond nameplate — size the motor and starter accordingly.
Environmental and compliance — approvals and temperature derating
For a panel in a hot plant (say 50 °C ambient), expect to derate the continuous current — the exact curve is in the product manual, but plan for roughly 1% per °C above 40. Shock resistance is 15 g / 11 ms, meeting typical industrial vibration requirements. Approvals include UL, CSA, and CE marking, covering North American and European installations. ATEX and IECEx are also present for hazardous areas.
Sourcing and lifecycle — current production, quoted to order
Lifecycle status is current production — no end-of-life notice or last-time-buy window.