{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-4DE27-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-4DE27-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-4DE27-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-4DE27-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-4DE27-0FB4 direct-on-line motor starter, size S0, 11 kW at 400 V AC-3, Class 10 thermal bimetallic overload, magnetic short-circuit trip, spring-loaded terminals, 45 x 107 x 243 mm.","salesMarkdown":"## Size S0 direct-on-line starter — what it packs The 3RA2125-4DE27-0FB4 is a Siemens SIRIUS direct-on-line starter, size S0, combining a contactor, thermal bimetallic overload relay (Class 10), and magnetic short-circuit release in one assembly. It ships with the contactor 3RT2027-2FB40, link module 3RA2921-2AA00, and circuit breaker 3RV2021-4DA25 — a matched set for motor starting and protection up to 11 kW at 400 V AC-3. ## Mounting and terminal reality Both main and auxiliary/control circuits use spring-loaded terminals — no screw torquing needed, which speeds panel wiring and reduces connection errors. Dimensions are 45 mm wide, 107 mm deep, 243 mm tall — the S0 footprint fits standard motor starter bays in distribution panels. ## Duty ratings and thermal limits Rated 11 kW at 400 V AC-3 (max 690 V AC-3), 50/60 Hz — the AC-3 rating covers squirrel-cage motor switching, where the starter makes and breaks stalled-rotor current. Operating temperature range is -20 to +60 °C, with 10 to 95 % relative humidity; surge voltage resistance is 6 kV, adequate for industrial mains with typical transient levels. ## Lifecycle and sourcing — active, quoted to order No stock-holding claim — quoted per order.","metaTitle":"Siemens 3RA2125-4DE27-0FB4 SIRIUS Motor Starter","metaDescription":"Siemens 3RA2125-4DE27-0FB4 SIRIUS direct-on-line starter, size S0, 11 kW at 400 V AC-3, Class 10 trip, spring terminals. Active production, quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","title":"3RA2125-4DE27-0FB4","Height":"243 mm","Upwards":"50 mm","Forwards":"20 mm","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"20 mm","Rated Value":"24 ... 24 V","description":"Load feeder fuseless, Direct-on-line starting 400 V AC, Size S0 18...25 A 24 V DC Spring-type terminal for installation on standard mounting rail (also fulfills type of coordination 1) Type of coordination 2, Iq = 150 kA 1 NO+1 NC (contactor) with diode combination plugged in at the front","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-50 ... +80 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail","Mounting Position":"vertical","PROFIsafe protocol":"No","Product Brand Name":"SIRIUS","Type Of Assignment":"2","Product Designation":"Direct (on-line) starter","Size Of Load Feeder":"S0","PROFINET IO protocol":"No","at 400 V rated value":"11 000 W","Design Of The Product":"for standard rail or screw mounting","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","Of The Supplied Contactor":"3RT2027-2FB40","Of The Supplied Link Module":"3RA2921-2AA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","Design Of The Overload Release":"thermal (bimetallic)","Design Of The Switching Contact":"electromechanical","Operating Frequency Rated Value":"50 ... 60 Hz","Design Of The Short-Circuit Trip":"magnetic","Of The Supplied Circuit-Breakers":"3RV2021-4DA25","degree of protection NEMA rating":"other","For Auxiliary And Control Circuit":"spring-loaded terminals","Product Extension Auxiliary Switch":"Yes","Relative Humidity During Operation":"10 ... 95 %","Surge Voltage Resistance Rated Value":"6 kV","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","protocol is supported AS-Interface protocol":"No","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","shock resistance according to IEC 60068-2-27":"6g / 11 ms","Type Of Voltage Of The Control Supply Voltage":"DC","at 400 V according to IEC 60947-4-1 rated value":"150 000 A","operational current at AC-3 at 400 V rated value":"22 A","Mechanical Service Life (Switching Cycles) Of Contactor Typical":"10 000 000","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"18 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/b7b0e3b4f21fa59eab9801f7deaec51a.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=552603&mlfb=3RA2125-4DE27-0FB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-4DE27-0FB4","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/3RA2125-4DE27-0FB4 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T19:47:38.189Z","lastPublished":"2026-07-22T19:47:38.189Z","indexable":true}}