{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-1JA24-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-1JA24-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-1JA24-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-1JA24-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS direct on-line starter, 3RA2120-1JA24-0BB4, Size S0, 10 A AC-3 at 400 V, Trip Class 10, 24 VDC coil, screw-type terminals, snap-on DIN rail mounting.","salesMarkdown":"The 3RA2120-1JA24-0BB4 is a Siemens SIRIUS direct on-line starter combining a contactor and overload relay in one Size S0 package. Trip Class 10 matches the thermal characteristic of standard induction motors, tripping within 10 seconds at locked-rotor current. The 24 VDC coil holds in on a 24 V nominal supply. ## Mounting and integration — DIN rail or screw-fixed Clearance: 50 mm upwards, 20 mm forwards, 20 mm at the side, 10 mm downwards, 0 mm backwards (–) — the 0 mm rear clearance means it can sit flush against a panel backplane. ## Lifecycle and sourcing — active, fully traceable The supplied contactor is 3RT2024-1BB40 and the link module is 3RA2921-1BA00. If you are replacing an older SIRIUS load feeder, the mounting footprint and terminal layout are consistent across the S0 frame size. No adapter plate needed for a direct swap in an existing panel. ## Chain of custody — what to verify on receipt For a part that protects a motor branch circuit, counterfeit or re-marked stock can mean a misrated overload that fails to trip. Verify the date code on the Siemens nameplate matches the packaging label. The 24 VDC coil marking should be legible and laser-etched, not a stick-on label. Full traceability back to Siemens factory batch records is available through authorised distribution channels only. A loose power connection on a motor starter is a common root cause of nuisance tripping and contactor welding.","metaTitle":"Siemens 3RA2120-1JA24-0BB4 SIRIUS Direct Starter","metaDescription":"Siemens 3RA2120-1JA24-0BB4 SIRIUS direct on-line starter, 10 A AC-3 at 400 V, Trip Class 10, 24 VDC coil, Size S0. Currently in production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","title":"3RA2120-1JA24-0BB4","Height":"193 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 7.00...10.0 A 24 V DC screw 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)","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 DIN 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 230 V rated value":"1.5 hp","at 400 V rated value":"4 000 kW","at 480 V rated value":"10 A","at 600 V rated value":"10 A","Design Of The Product":"for standard rail or screw mounting","For Main Current Circuit":"screw-type terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"0.5 hp","at 200/208 V rated value":"3 hp","at 220/230 V rated value":"3 hp","at 460/480 V rated value":"7.5 hp","at 575/600 V rated value":"10 hp","Of The Supplied Contactor":"3RT2024-1BB40","Of The Supplied Link Module":"3RA2921-1BA00","Size Of The Circuit-Breaker":"S00","at AC-3 rated value maximum":"690 V","at AC-3 at 400 V rated value":"10 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"10 A","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":"3RV2011-1JA10","degree of protection NEMA rating":"other","For Auxiliary And Control Circuit":"screw-type 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":"3.4 W","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","protocol is supported AS-Interface protocol":"No","with high demand rate according to SN 31920":"73 %","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":"130 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":"7 ... 10 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/623bc770a2886429ef16df0d4094e133.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=124669&mlfb=3RA2120-1JA24-0BB4"},"ai":{"faq":[{"question":"What is the difference between 3RA2120 and 3RA2121?","answer":"The 3RA2120 is a direct on-line (DOL) starter. The 3RA2121 is a reversing starter. Both share the S0 frame and similar ratings, but the reversing variant includes a mechanical interlock and two contactors for direction change."},{"question":"What are the wiring and mounting instructions for 3RA2120-1JA24-0BB4?","answer":"Mount vertically on 35 mm DIN rail or screw-fixed to a backplate. Maintain clearance: 50 mm above, 20 mm front, 20 mm sides, 10 mm below, 0 mm rear. Wire main circuit via screw-type terminals. The 24 VDC coil requires a clean DC supply; verify polarity and inrush current."},{"question":"Where can I buy 3RA2120-1JA24-0BB4 and what is the lead time?","answer":"This part is sourced to order against RFQ. 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/3RA2120-1JA24-0BB4","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/3RA2120-1JA24-0BB4 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}}