{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2125-1JE24-0FB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2125-1JE24-0FB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2125-1JE24-0FB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2125-1JE24-0FB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2125-1JE24-0FB4 direct on-line starter, size S0, 4 kW at 400 V AC-3, CLASS 10, 24 V DC coil, spring-loaded terminals, screw and snap-on 35 mm DIN rail mounting.","salesMarkdown":"## Motor protection and switching in a single package The 3RA2125-1JE24-0FB4: This covers the majority of three-phase motor applications in European and Asian voltage standards. It integrates a thermal bimetallic overload relay (CLASS 10 trip class) and a magnetic short-circuit release, so the same device handles both overload protection and fault interruption up to its breaking capacity. The supplied circuit-breaker is 3RV2021-1JA25. The 24 V DC control coil matches standard PLC output voltages, eliminating the need for an intermediate relay in most panels. Spring-loaded terminals on both main and control circuits reduce wiring time and eliminate the risk of screw-terminal loosening under vibration. ## Panel fit and mounting constraints Size S0 footprint: 243 mm height, 45 mm width, 107 mm depth. Mounts vertically on 35 mm standard DIN rail via the screw-and-snap-on method, or directly with screws through the mounting slots. Required clearance around the device: 50 mm above, 20 mm below, 20 mm to the side, and 20 mm forward. No clearance needed behind the rail. These distances ensure proper heat dissipation from the bimetallic overload and arc-quenching space for the contactor. Operating temperature range -20 to +60 °C with temperature compensation active across the full span. Storage and transport limits extend to -50 to +80 °C.","metaTitle":"Siemens 3RA2125-1JE24-0FB4 SIRIUS Direct Starter","metaDescription":"Siemens 3RA2125-1JE24-0FB4 SIRIUS direct on-line starter, size S0, 4 kW at 400 V AC-3, CLASS 10, 24 V DC coil, spring-loaded terminals.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","title":"3RA2125-1JE24-0FB4","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 7...10 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":"4 000 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":"3RT2024-2FB40","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":"3RV2021-1JA25","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":"8.5 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":"7 ... 10 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/416a019b598366fe291fcdaee2a195be.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=552539&mlfb=3RA2125-1JE24-0FB4"},"ai":{"faq":[{"question":"What is the trip class and what does it mean for motor protection?","answer":"This is the standard for general-purpose motor starting where the acceleration time is under 10 seconds."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2125-1JE24-0FB4","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/3RA2125-1JE24-0FB4 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}}