{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4074-2BB45","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4074-2BB45","canonicalUrl":"https://aoctrl.com/siemens/3RW4074-2BB45","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4074-2BB45","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4074-2BB45 soft starter, size S12, 280 A at 40 °C, 230 V AC 50/60 Hz, screw fixing, busbar main connection, with thyristors and motor overload protection.","salesMarkdown":"## 280 A at 40 °C — what that means for the motor it starts The 3RW4074-2BB45 is rated 280 A at 40 °C ambient. That is the continuous current the thyristors can carry with the heatsink at that temperature — not a starting surge, but the steady-state motor current after the ramp is complete. The operating frequency range is 50 to 60 Hz. ## Terminal sizing and connection — main circuit Main circuit connection is via busbar; the terminal range accepts stranded cable 70 to 240 mm² and fine-stranded 50 to 240 mm². For US installations, the range covers 2/0 to 500 kcmil using both clamping points, with a back clamping point accepting 250 to 500 kcmil. That is a big cable fit — this unit expects a serious feeder. ## Protection and control features built in Motor overload protection is integrated — no separate overload relay needed for most applications. Adjustable current limitation lets you set the start current below the locked-rotor value, which reduces mechanical shock and line drop. External reset is supported, and intrinsic device protection covers the soft starter itself against overtemperature and phase imbalance. The minimum load is 20 % of the rated current — below that the motor might not ramp up cleanly. Pollution degree 3 per IEC 60947-4-2 confirms it is rated for conductive-dust industrial environments. ## Mounting and thermal management The mounting position is flexible: with an additional fan, the unit can be mounted vertically with +/-90° rotation and +/-22.5° tilt front/back; without the fan, +/-10° rotation and +/-10° tilt. The derating temperature starts at 40 °C. Overall dimensions: width 160 mm, height 230 mm, depth 278 mm. Clearances: 100 mm upwards, 75 mm downwards, 5 mm at the sides. Storage temperature range -40 to +80 °C; operating range -25 to +60 °C. Maximum motor cable length is 300 m.","metaTitle":"Siemens 3RW4074-2BB45 Soft Starter, SIRIUS, 280A, 230V","metaDescription":"Siemens 3RW4074-2BB45 SIRIUS soft starter, 280 A at 40 °C, 230 V, size S12. Active production, quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Soft Starters"],"specifications":{"Depth":"278mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"160mm","title":"3RW4074-2BB45","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S12 280 A, 200 kW/500 V, 40 °C 400-600 V AC, 230 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5074-2AB15<<","During Storage":"-40 ... +80°C","External Reset":"Yes","Finely Stranded":"50 ... 240 mm²","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw fixing","Minimum Load [%]":"20%","For Main Contacts":"2/0 ... 500 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":"280A","at 50 °C rated value":"248A","at 60 °C rated value":"215A","For Auxiliary Contacts":"2x (24 ... 16)","For Main Current Circuit":"busbar connection","Motor Overload Protection":"Yes","Using Both Clamping Points":"min. 2x 2/0, max. 2x 500 kcmil","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Size Of Engine Control Device":"S12","Using The Back Clamping Point":"250 ... 500 kcmil","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"3/0 ... 600 kcmil","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"red","Integrated Bypass Contact System":"Yes","For Auxiliary And Control Circuit":"spring-loaded 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 (0.25 ... 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":"200kW","at standard circuit at 50 °C rated value":"250hp","Finely Stranded Without Core End Processing":"min. 2x 50 mm², max. 2x 185 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":"400 ... 600V","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%","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":"90W","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":"130A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/5ba53e91ebb97fab22a7da3e67bc37bf.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=431990&mlfb=3RW4074-2BB45"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4074-2BB45","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/3RW4074-2BB45 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}}