{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4038-2BB14","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4038-2BB14","canonicalUrl":"https://aoctrl.com/siemens/3RW4038-2BB14","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4038-2BB14","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS soft starter, 3RW4038-2BB14, size S2, rated 72 A at 40 °C, 110...230 V DC control supply, with integrated bypass contactor.","salesMarkdown":"## What the 72 A rating means for your motor load The Siemens 3RW4038-2BB14 is a SIRIUS soft starter rated 72 A at 40 °C, which means it handles motor starting current for loads up to roughly 37 kW on a 400 V three-phase system — the current rating is the one that governs the real motor fit, not the frame size. The integrated bypass contactor means the thyristors are shorted out once the motor is up to speed, so heat dissipation in the cabinet drops to near zero during run — a real advantage for dense DIN-rail layouts where every watt counts. ## Panel integration — DIN rail and clearances Clearance rules: 60 mm upwards, 40 mm downwards, 30 mm at the side. If you add the optional fan, the mounting surface can tilt ±90° rotatable and ±22.5° front-to-back; without the fan, only ±10° rotatable and ±10° tilt. ## Wiring and control connections Main power circuit uses screw-type terminals accepting 2x (1.5... 25 mm²) stranded or 2x (0.25... 2.5 mm²) solid. Auxiliary and control circuits use spring-loaded terminals for 2x (24... 14) AWG. Control supply voltage is 110...230 V DC — note that's DC only, not AC, so don't feed it from a standard 230 V AC control transformer without a rectifier. The maximum motor cable length is 300 m.","metaTitle":"Siemens 3RW4038-2BB14 SIRIUS Soft Starter, 72 A, Size S2","metaDescription":"Siemens 3RW4038-2BB14 SIRIUS soft starter, 72 A rated at 40 °C, size S2. Integrated bypass, 110-230 V DC control supply. Active lifecycle, available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Soft Starters"],"specifications":{"Depth":"170mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"55mm","title":"3RW4038-2BB14","Height":"160mm","Upwards":"60mm","Stranded":"2x (1.5 ... 25 mm²)","Downwards":"40mm","Thyristors":"Yes","At The Side":"30mm","description":"SIRIUS soft starter S2 72 A, 37 kW/400 V, 40 °C 200-480 V AC, 110-230 V AC/DC spring-type terminals","During Storage":"-40 ... +80°C","External Reset":"Yes","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw and snap-on mounting","Minimum Load [%]":"20%","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 40 °C rated value":"72A","at 50 °C rated value":"62A","at 60 °C rated value":"60A","For Auxiliary Contacts":"2x (24 ... 14)","For Main Current Circuit":"screw-type terminals","Motor Overload Protection":"Yes","Using Both Clamping Points":"2x (16 ... 2)","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Size Of Engine Control Device":"S2","Using The Back Clamping Point":"16 ... 2","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"18 ... 2","control supply voltage 1 at DC":"110 ... 230V","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","control supply voltage 1 at AC at 50 Hz":"110 ... 230V","control supply voltage 1 at AC at 60 Hz":"110 ... 230V","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":"37kW","at standard circuit at 50 °C rated value":"40hp","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/DC","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 ... 480V","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 at DC":"-15%","relative positive tolerance of the control supply voltage at DC":"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":"15W","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":"35A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$652.78","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/b8002bb49dc6ffe79d231817dea2215b.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=500727&mlfb=3RW4038-2BB14"},"ai":{"faq":[{"question":"What is the mounting position for 3RW4038-2BB14?","answer":"With the optional fan, the mounting surface allows ±90° rotation and ±22.5° front-to-back tilt. Without the fan, only ±10° rotation and ±10° tilt are permitted."},{"question":"Where can I buy 3RW4038-2BB14?","answer":"This part is sourced to order; availability and pricing are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4038-2BB14","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/3RW4038-2BB14 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}}