{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4038-1TB04","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4038-1TB04","canonicalUrl":"https://aoctrl.com/siemens/3RW4038-1TB04","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4038-1TB04","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4038-1TB04 soft starter, size S2, 72 A at 40 °C, 50/60 Hz, screw terminals, integrated bypass, adjustable current limitation, motor overload protection.","salesMarkdown":"The Siemens SIRIUS 3RW4038-1TB04 is a size S2 soft starter rated 72 A at 40 °C, 62 A at 50 °C, and 60 A at 60 °C — so the 40 °C figure is the one to spec against for a standard panel environment; above that, the 50 °C and 60 °C ratings give you the thermal derating curve without guessing. It uses thyristors for the soft-start ramp and includes an integrated bypass contact system, which means the thyristors are only in circuit during start/stop — no continuous dissipation from the semiconductors once the motor is at speed. Mounting is screw and snap-on, sized for a 55 mm wide footprint on DIN rail or a backplate; the size S2 frame keeps it compact for a 72 A device. Clearance requirements: 60 mm above, 40 mm below, 30 mm at the sides — plan the enclosure layout accordingly, especially if you're adding the optional fan (which changes the allowable mounting angles). Main circuit connections use screw-type terminals accepting 2x (1.5... 25 mm²) stranded or 2x (0.5... 2.5 mm²) solid; auxiliary contacts take 2x (20... 14) AWG. The back and front clamping points each handle 16... 2 AWG. Operating temperature range is -25... +60 °C; storage from -40... +80 °C. Derating starts at 40 °C, which the 50 °C and 60 °C current ratings already reflect. Minimum load is 20 % of the rated current — below that, the soft starter may not trigger the thyristors reliably, so don't use it on a motor drawing less than about 14.4 A at 40 °C ambient. No inside-delta circuit configuration — this is a standard in-line soft starter, not a six-wire delta variant. Maximum motor cable length is 300 m. External reset input is available; fault indication via a red display.","metaTitle":"Siemens SIRIUS 3RW4038-1TB04 Soft Starter, 72A at 40°C, Size","metaDescription":"Siemens SIRIUS 3RW4038-1TB04 soft starter, 72 A at 40 °C, size S2, integrated bypass, adjustable current limit, motor overload protection, pollution degree 3. Active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Soft Starters"],"specifications":{"Depth":"170mm","Solid":"2x (0.5 ... 2.5 mm²)","Width":"55mm","title":"3RW4038-1TB04","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, 24 V AC/DC Screw terminals Thermistor motor protection","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 50 Hz rated value":"24V","at 60 Hz rated value":"24V","at 40 °C rated value":"72A","at 50 °C rated value":"62A","at 60 °C rated value":"60A","For Auxiliary Contacts":"2x (20 ... 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","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":"Yes","at standard circuit at 40 °C rated value":"37kW","at standard circuit at 50 °C rated value":"40hp","control supply voltage 1 at DC rated value":"24V","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%","For Auxiliary Contacts Finely Stranded With Core End Processing":"2x (20 ... 16)","relative negative tolerance of the control supply voltage at DC":"-20%","relative positive tolerance of the control supply voltage at DC":"20%","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":"$726.44 – $1,268.00","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/22835c81d6d3353b42510ba6bb43e98f.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=21578&mlfb=3RW4038-1TB04"},"ai":{"faq":[{"question":"What are the key ratings for 3RW4038-1TB04?","answer":"Rated 72 A at 40 °C, 62 A at 50 °C, 60 A at 60 °C; insulation voltage 600 V; operating frequency 50/60 Hz; control supply 24 V AC at both frequencies."},{"question":"What are the mounting dimensions and clearances?","answer":"Width 55 mm, height 160 mm, depth 170 mm. Required clearances: 60 mm above, 40 mm below, 30 mm at the sides."},{"question":"Does it include motor overload protection?","answer":"Yes, motor overload protection is built in, along with adjustable current limitation and intrinsic device protection."},{"question":"What wire sizes does it accept?","answer":"Main circuit screw terminals accept 2x (0.5... 2.5 mm²) solid or 2x (1.5... 25 mm²) stranded; auxiliary contacts accept 2x (20... 14) AWG."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4038-1TB04","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/3RW4038-1TB04 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}}