{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-4DH27-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-4DH27-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-4DH27-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-4DH27-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-4DH27-0FB4 direct online starter, S0 size, 25 A AC-3 at 400 V, Class 10, for 60 mm busbar systems, spring-loaded terminals.","salesMarkdown":"## SIRIUS direct starter — S0 frame, 25 A AC-3, Class 10 The 3RA2125-4DH27-0FB4: The starter ships pre-assembled with a 3RT2027-2FB40 contactor and a 3RA2921-2AA00 link module — the contactor and overload are coordinated as a matched pair, so the SCCR and selectivity curves are validated out of the box. ## Busbar snap-on and panel integration Designed for snapping onto 60 mm busbar systems — the S0 footprint clips directly onto the busbar without a separate mounting plate, saving DIN-rail space in a motor control centre. Mounting position is vertical only; the 165 mm depth, 45 mm width, and 260 mm height fit standard S0 feeder slots. Clearance requirements: 50 mm upwards, 20 mm forwards, 10 mm downwards, 20 mm at the side, 0 mm backwards — plan the enclosure depth and cable bend radius accordingly. Main circuit connections use spring-loaded terminals — no screw torque verification needed, and the cage clamp holds the conductor against thermal cycling better than a screw clamp in high-vibration busbar environments. ## Active production — sourcing posture Operating temperature range is -20 to +60 °C with temperature compensation active across the same band — suitable for panel environments without derating up to the 60 °C ceiling. Storage and transport limits are -50 to +80 °C, so the starter can sit in an unheated warehouse or ship in a non-climate-controlled container without damage.","metaTitle":"Siemens 3RA2125-4DH27-0FB4 SIRIUS Direct Starter, 25 A AC-3","metaDescription":"Siemens 3RA2125-4DH27-0FB4 SIRIUS direct online starter, 25 A at 400 V AC-3, Class 10, S0 frame, 60 mm busbar mount. Active production, quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"165 mm","Width":"45 mm","title":"3RA2125-4DH27-0FB4","Height":"260 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 60 mm busbar systems (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":"for snapping onto 60 mm busbar systems","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 230 V rated value":"3 hp","at 400 V rated value":"11 000 kW","at 480 V rated value":"25 A","at 600 V rated value":"25 A","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"2 hp","at 200/208 V rated value":"7.5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"20 hp","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","at AC-3 at 400 V rated value":"25 A","at AC-3e rated value maximum":"690 V","at AC-3e at 400 V rated value":"25 A","Design Of The Overload Release":"thermal (bimetallic)","Of The Supplied Busbar Adapter":"8US1251-5NT11","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 %","Without Load Current Share Typical":"5.9 W","holding power of magnet coil at DC":"5.9 W","Surge Voltage Resistance Rated Value":"6 kV","at AC in hot operating state per pole":"5.8 W","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","reference code according to IEC 81346-2:2019":"Q","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","Mechanical Service Life (Operating Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"325 A","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/28de7339cf0221ecf8e5e78fac5bf9df.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=553447&mlfb=3RA2125-4DH27-0FB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-4DH27-0FB4","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/3RA2125-4DH27-0FB4 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}}