{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4055-6BB44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4055-6BB44","canonicalUrl":"https://aoctrl.com/siemens/3RW4055-6BB44","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4055-6BB44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS soft starter, 3RW4055-6BB44, size S6, 134 A at 40 °C, 230 V 50/60 Hz, thyristor-based, screw fixing.","salesMarkdown":"The Siemens 3RW4055-6BB44 is a SIRIUS soft starter, size S6, designed to ramp induction motors up to speed and protect them during start. It uses thyristors to control voltage, so the motor sees a gradual increase rather than a full-voltage slam. The unit is rated 134 A at 40 °C, 230 V at both 50 and 60 Hz, and carries motor overload protection and adjustable current limitation built in. But if your panel runs hotter, derate: 117 A at 50 °C, 100 A at 60 °C. The minimum load is 20% of the rated current, so a motor drawing less than about 27 A won't trigger the internal protection correctly. Mounting is screw fixing. The unit is 250 mm deep, 120 mm wide, 198 mm tall. Clearance: 100 mm above, 75 mm below, only 5 mm at the sides — tight side clearance means you can stack them close. The main current circuit connects via busbar; main contacts accept 4 to 250 kcmil. For the control circuit, solid wire 2x (0.5 to 2.5 mm²) or stranded 2x (25 to 120 mm²). Auxiliary contacts accept 2x (20 to 14 AWG). Maximum motor wire length is 300 m — keep that in mind for long cable runs.","metaTitle":"Siemens 3RW4055-6BB44 SIRIUS Soft Starter, 134A at 40°C, Siz","metaDescription":"Siemens 3RW4055-6BB44 SIRIUS soft starter, current production. Rated 134A at 40°C, 230V 50/60 Hz, size S6. Thyristor-based, adjustable current limitation, motor overload protection","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"250mm","Solid":"2x (0.5 ... 2.5 mm²)","Width":"120mm","title":"3RW4055-6BB44","Height":"198mm","Upwards":"100mm","Stranded":"2x (25 ... 120 mm²)","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S6 134 A, 75 kW/400 V, 40 °C 200-460 V AC, 230 V AC Screw terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5055-6AB14<<","During Storage":"-40 ... +80°C","External Reset":"Yes","Finely Stranded":"2x (16 ... 95 mm²)","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw fixing","Minimum Load [%]":"20%","For Main Contacts":"4 ... 250 kcmil","Mounting Position":"With additional fan: With vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back Without additional fan: With vertical mounting surface +/-10° rotatable, with vertical mounting surface +/- 10° t","Product Brand Name":"SIRIUS","Degree Of Pollution":"3, acc. to IEC 60947-4-2","Product Designation":"Soft starter","Wire Length Maximum":"300m","Derating Temperature":"40°C","Inside-Delta Circuit":"No","at 50 Hz rated value":"230V","at 60 Hz rated value":"230V","at 40 °C rated value":"134A","at 50 °C rated value":"117A","at 60 °C rated value":"100A","For Auxiliary Contacts":"2x (20 ... 14)","For Main Current Circuit":"busbar connection","Motor Overload Protection":"Yes","Using Both Clamping Points":"max. 2x 1/0","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Size Of Engine Control Device":"S6","Using The Back Clamping Point":"6 ... 2/0","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"6 ... 2/0","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"red","Integrated Bypass Contact System":"Yes","For Auxiliary And Control Circuit":"screw-type terminals","Product Component Motor Brake Output":"No","during storage according to IEC 60721":"1K6 (only occasional condensation), 1C2 (no salt mist), 1S2 (sand must not get inside the devices), 1M4","reference code according to EN 61346-2":"Q","during operation according to IEC 60721":"3K6 (no formation of ice, no condensation), 3C3 (no salt mist), 3S2 (sand must not get into the devices), 3M6","during transport according to IEC 60721":"2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m)","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Evaluation Of Thermistor Motor Protection":"No","at standard circuit at 40 °C rated value":"75kW","at standard circuit at 50 °C rated value":"75hp","Finely Stranded Without Core End Processing":"max. 1x 50 mm², 1x 70 mm²","number of CO contacts for auxiliary contacts":"1","number of NC contacts for auxiliary contacts":"0","number of NO contacts for auxiliary contacts":"2","Type Of Voltage Of The Control Supply Voltage":"AC","Control Supply Voltage Frequency 1 Rated Value":"50Hz","Control Supply Voltage Frequency 2 Rated Value":"60Hz","Installation Altitude At Height Above Sea Level":"5 000m","continuous operating current [% of Ie] at 40 °C":"115%","Operating Voltage At Standard Circuit Rated Value":"200 ... 460V","contact rating of auxiliary contacts according to UL":"B300 / R300","Relative Negative Tolerance Of The Operating Frequency":"-10%","Relative Positive Tolerance Of The Operating Frequency":"10%","For Auxiliary Contacts Finely Stranded With Core End Processing":"2x (20 ... 16)","Relative Negative Tolerance Of The Control Supply Voltage Frequency":"-10%","Relative Positive Tolerance Of The Control Supply Voltage Frequency":"10%","Relative Negative Tolerance Of The Operating Voltage At Standard Circuit":"-15%","Relative Positive Tolerance Of The Operating Voltage At Standard Circuit":"10%","power loss [W] at operational current at 40 °C during operation typical":"60W","relative negative tolerance of the control supply voltage at AC at 50 Hz":"-15%","relative negative tolerance of the control supply voltage at AC at 60 Hz":"-15%","relative positive tolerance of the control supply voltage at AC at 50 Hz":"10%","relative positive tolerance of the control supply voltage at AC at 60 Hz":"10%","Adjustable Motor Current For Motor Overload Protection Minimum Rated Value":"59A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1,221.00 – $2,028.00","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/31334e31e9dfacd9ed274aed01af786d.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=127649&mlfb=3RW4055-6BB44"},"ai":{"faq":[{"question":"What are the key ratings for this soft starter?","answer":"Rated 134 A at 40 °C, 230 V at 50/60 Hz, size S6. Insulation voltage 600 V, minimum load 20%. Derates to 117 A at 50 °C and 100 A at 60 °C."},{"question":"What clearance is needed around the unit?","answer":"100 mm above, 75 mm below, 5 mm at the sides. Depth is 250 mm, width 120 mm, height 198 mm. Mounting is screw fixing."},{"question":"Does it include motor overload protection?","answer":"Yes, motor overload protection is built in, along with adjustable current limitation and intrinsic device protection. External reset is supported."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4055-6BB44","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RW4055-6BB44 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}