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Siemens 3RW5055-6TB05 — Soft Starters

Siemens 3RW5055-6TB05 Soft Starter, 68 A Min

MPN3RW5055-6TB05
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Siemens SIRIUS 3RW5055-6TB05 soft starter, 68 A minimum, Trip Class 10A / 10E / 20E, rated 200–600 V, ATEX, IECEx, UL, CSA, PROFIBUS, Modbus RTU/TCP, EtherNet/IP.

Siemens 3RW5055-6TB05 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RW5055-6TB05 — Identification
ParameterValue
Product designationSoft starter
Product brand nameSIRIUS
3RW5055-6TB05 — Power & Motor Rating
ParameterValue
Rated motor power at 400 V (40 °C)75 kW
Rated motor power at 230 V (40 °C)37 kW
Rated operational current at 40 °C143 A
Rated operational current at 50 °C128 A
Rated operational current at 60 °C118 A
Rated insulation voltage600 V
Minimum settable current (% of Ie)15 %; Relative to smallest settable Ie
Power loss during startup (50 °C)1 134 W
3RW5055-6TB05 — Control & Connection
ParameterValue
Control supply voltage typeAC/DC
Rated voltage at 50 Hz24 V
Rated voltage at 60 Hz24 V
Main circuit terminal typebusbar connection
Control circuit wire range, solid1x (0.5 ... 4.0 mm²), 2x (0.5 ... 2.5 mm²)
Control circuit wire range, finely stranded (with ferrule)1x (0.5 ... 2.5 mm²), 2x (0.5 ... 1.5 mm²)
Analog outputNo
Auxiliary contact rated current, AC-15 at 250 V3 A
Control supply voltage tolerance, AC 50 Hz (max.)20 %
Control supply voltage tolerance, AC 50 Hz (min.)-20 %
Control supply voltage tolerance, AC 60 Hz (max.)20 %
Control supply voltage tolerance, AC 60 Hz (min.)-20 %
Control supply frequency tolerance (max.)10 %
Control supply frequency tolerance (min.)-10 %
Operating frequency tolerance (max.)10 %
Operating frequency tolerance (min.)-10 %
3RW5055-6TB05 — Protection & Features
ParameterValue
Motor overload protectionYes; Full motor protection (thermistor motor protection and electronic motor overload protection)
Thermistor motor protectionYes; Type A PTC or Klixon / Thermoclick
Adjustable current limitationYes
Intrinsic device protectionYes
Pollution degree3, acc. to IEC 60947-4-2
3RW5055-6TB05 — Mechanical
ParameterValue
Height198 mm
Width120 mm
Depth249 mm
Weight3.2 kg
Mounting positionwith vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back
Fastening methodscrew fixing
Mounting clearance, top100 mm
Mounting clearance, bottom75 mm
Mounting clearance, side5 mm
Mounting clearance, front10 mm
3RW5055-6TB05 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C; Please observe derating at temperatures of 40 °C or above
Storage / transport temperature range-40 ... +80 °C
Max. installation altitude5 000 m; derating as of 1000 m, see Manual
Ambient class during operation (IEC 60721)3K6 (no ice formation, only occasional condensation), 3C3 (no salt mist), 3S2 (sand must not get into the devices), 3M6
Ambient class during transport (IEC 60721)2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m)
3RW5055-6TB05 — Specifications
ParameterValue
Trip ClassCLASS 10A / 10E (preset) / 20E; acc. to IEC 60947-4-2
Number Of Controlled Phases2
Utilization category according to IEC 60947-4-2AC-53a
Product Feature Integrated Bypass Contact SystemYes
Start-Up Ramp Time Of Soft Starter0 ... 20 s
Ramp-Down Time Of Soft Starter0 ... 20 s
3RW5055-6TB05 — Electrical
ParameterValue
Current Limiting Value [%] Adjustable130 ... 700 %
Starting Voltage [%]30 ... 100 %
Stopping Voltage [%]50 %; non-adjustable

Product details

What the trip class means for your motor start

The Siemens 3RW5055-6TB05 soft starter is a SIRIUS-series hybrid switching device rated for a minimum motor current of 68 A and a supply voltage range of 200–600 V. Its Trip Class is selectable as CLASS 10A, 10E (preset), or 20E per IEC 60947-4-2 — that means the overload protection curve is matched to the motor's thermal limit during start. CLASS 10A is the fastest trip, protecting standard squirrel-cage motors on normal starts; CLASS 20E gives more headroom for high-inertia loads like centrifuges or crushers where the start takes longer. The preset 10E is a middle ground for most pump and fan applications.

Fieldbus and control integration

This unit carries onboard PROFIBUS, Modbus RTU, Modbus TCP, and EtherNet/IP, plus PROFINET standard with PROFIenergy support when paired with the PROFINET communication module. That covers the major industrial Ethernet and fieldbus topologies without needing a separate gateway. The control supply is 24 V DC. Remote reset is done by cycling the control supply voltage off and on. An error logbook is available but only with special accessories — factor that in if your plant relies on event logging for predictive maintenance.

Mounting is screw-fix to a vertical surface, rotatable ±90° and tiltable ±22.5° front-to-back. Clearances: 100 mm upwards, 75 mm downwards, 10 mm forwards, 0 mm backwards, 5 mm at the sides. The unit measures 120 mm wide × 198 mm high × 249 mm deep. Shock resistance is 15 g / 11 ms, dropping to 12 g / 11 ms if contact lifting is a concern.

Frequently asked questions

Does 3RW5055-6TB05 support Modbus TCP communication?

Yes, the 3RW5055-6TB05 supports Modbus TCP, Modbus RTU, PROFIBUS, and EtherNet/IP, plus PROFINET standard with PROFIenergy when using the PROFINET communication module.

What is the trip class of 3RW5055-6TB05?

The trip class is selectable as CLASS 10A, 10E (preset), or 20E per IEC 60947-4-2. CLASS 10A is fastest for standard motors; CLASS 20E gives longer start time for high-inertia loads.

Where can I buy 3RW5055-6TB05 soft starter?

This unit is sourced to order; availability and pricing are confirmed at quote time.

MPN
3RW5055-6TB05