The Siemens 3RW5548-6HA16 is a SIRIUS soft starter rated for 200... 690 V supply. That voltage range covers standard low-voltage networks worldwide — 208 V, 400 V, 480 V, 600 V — without needing a separate transformer tap. The trip class is field-selectable among CLASS 10A / 10E (default) / 20E / 30E per IEC 60947-4-2. CLASS 10A is the tightest thermal curve for standard motor starts; CLASS 30E gives extra time for high-inertia loads like centrifuges or large fans. The service factor of 1.15 means the starter can handle a 15 % continuous overload above nameplate without tripping — useful for pumps or compressors that occasionally run at the edge of their rating. ATEX and IECEx certification qualifies this unit for installation in potentially explosive atmospheres — Zone 1, Zone 2 gas or Zone 21, Zone 22 dust areas. That makes it a direct fit for chemical plants, oil-and-gas facilities, grain handling, or paint lines where a standard soft starter would not be permitted.
Communication and control options
This soft starter ships with onboard PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP. The analog output is configurable as 4... 20 mA (default) or 0... 10 V. Torque control, breakaway pulse, DC braking, and pump ramp down are all built in. Torque control is useful for conveyors that need a soft start under varying load; the breakaway pulse cracks a stuck pump impeller before the ramp begins. Pump ramp down reduces water hammer on long discharge lines. Voltage ramp is the standard starting profile for most applications.
Approvals include CE marking, UL, and CSA. That covers European, US, and Canadian installations without additional agency review.
Physical integration
Dimensions are 210 mm wide, 393 mm high, 203 mm deep. The screw-terminal connection is standard for panel wiring — no special crimp tooling required. Clearance requirements: 100 mm upwards, 75 mm downwards, 10 mm forwards, 5 mm at the side, and 0 mm backwards. That backwards zero means the unit can sit flush against a back panel or mounting plate, saving enclosure depth.