{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4075-2BB44","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4075-2BB44","canonicalUrl":"https://aoctrl.com/siemens/3RW4075-2BB44","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4075-2BB44","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4075-2BB44 soft starter, size S12, 356 A at 40 °C, 50/60 Hz, 230 V rated control supply, thyristor-based, adjustable current limitation, integrated motor overload protection.","salesMarkdown":"## Rated current and thermal derating — sizing for the real ambient The 3RW4075-2BB44 is rated 356 A at 40 °C ambient. The derating temperature is 40 °C — above that, the continuous current must be reduced per the curve. If the panel ambient runs at 50 °C, size the motor FLA against 315 A, not the headline 356 A. ## Mounting and panel integration — size S12 constraints Physical dimensions: 230 mm height, 160 mm width, 278 mm depth. Fastening method is screw fixing — no DIN-rail clip on this size. Mounting position allows vertical surface with ±10° tilt without additional fan; with the optional fan, ±90° rotation and ±22.5° tilt front-to-back. Clearance requirements: 100 mm upwards, 75 mm downwards, 5 mm at the sides. The main circuit connection accepts busbar or cable: stranded 70–240 mm², finely stranded 50–240 mm², or 2/0–500 kcmil. ## Protection and control features — what the thyristor stack delivers Thyristor-based firing with adjustable current limitation — set the starting current between 20% and the rated current to match the load's breakaway torque without mechanical shock. Minimum load is 20%; below that the soft starter may not trigger reliably. Integrated motor overload protection and intrinsic device protection — the soft starter monitors both the motor and its own thyristor junction temperature. External reset input allows remote fault clearing. Maximum motor cable length is 300 m — beyond that, reflected wave voltage spikes may damage the motor insulation. Inside-delta circuit is not supported — this is a standard in-line configuration. Insulation voltage rated 600 V.","metaTitle":"Siemens 3RW4075-2BB44 Soft Starter, 356 A, SIRIUS S12","metaDescription":"Siemens 3RW4075-2BB44 SIRIUS soft starter, 356 A at 40 °C, size S12, active production. Quoted to order against RFQ.","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":"3RW4075-2BB44","Height":"230mm","Upwards":"100mm","Stranded":"70 ... 240 mm²","Downwards":"75mm","Thyristors":"Yes","At The Side":"5mm","description":"SIRIUS soft starter S12 356 A, 200 kW/400 V, 40 °C 200-460 V AC, 230 V AC spring-type terminals!!! Phased-out product!!! Successor is SIRIUS 3RW5, Preferred successor type is >>3RW5075-2AB14<<","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":"356A","at 50 °C rated value":"315A","at 60 °C rated value":"280A","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":"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%","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":"125W","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":"131A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$3,216.91","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/6f29a6f8a5e6297b7fc3f98c589afb0d.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=4482&mlfb=3RW4075-2BB44"},"ai":{"faq":[{"question":"What is the maximum motor cable length for the 3RW4075-2BB44?","answer":"Maximum motor cable length is 300 m. Beyond this distance, reflected wave transients from the thyristor switching can stress the motor winding insulation. For longer runs, consider an output reactor or a drive with a dV/dt filter."},{"question":"What is the minimum load current the 3RW4075-2BB44 can start?","answer":"Minimum load is 20% of the rated current. Below this threshold, the soft starter may not reliably detect the motor current zero-crossing for phase-angle control. For very light loads, a smaller soft starter or a contactor bypass should be considered."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4075-2BB44","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/3RW4075-2BB44 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}}