{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-1JD24-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-1JD24-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-1JD24-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-1JD24-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-1JD24-0BB4 direct-on-line motor starter, Size S0, AC-3 10 A at 400 V, 24 VDC coil, Class 10 trip, for 60 mm busbar systems.","salesMarkdown":"## SIRIUS direct-on-line starter, Size S0 — 10 A AC-3, 24 VDC coil The 3RA2120-1JD24-0BB4: It's a factory-combined unit — the supplied contactor is a 3RT2024-1BB40 and the link module is a 3RA2921-1BA00, so you're getting a coordinated starter package, not a loose pile of parts. The 24 VDC coil (24... 24 V) means this starter is a natural fit for modern PLC-controlled panels running a 24 VDC control bus — no separate AC control transformer needed for the starter itself. ## Mounting on 60 mm busbar systems — panel integration This starter is designed specifically for snapping onto 60 mm busbar systems — the mounting method is a fastening clip, not DIN rail. That makes it a good fit for Siemens 8US busbar systems or similar 60 mm-center distribution assemblies where you want to tap power directly off the bus without extra wiring. Mounting position is vertical only. The dimensions are 45 mm wide, 260 mm tall, and 165 mm deep — the width is the critical panel pitch dimension, and at 45 mm it fits standard S0 feeder spacing. Required clearances: 50 mm upward, 20 mm forward, 10 mm downward, 20 mm at the sides, and zero backward. That backward-zero clearance means it can sit flush against a panel backplate or busbar support. Main circuit connections are screw-type terminals — no spring-cage here, so factor in screwdriver torque time during panel build. The supplied link module (3RA2921-1BA00) bridges the contactor to the upstream circuit breaker, keeping the wiring between the protection and switching elements internal to the starter assembly. ## Duty ratings and motor sizing across voltages At 480 V and 600 V the current rating also holds at 10 A — so this starter handles the same 10 A motor load across the common North American and European voltage bands. Use the 10 A AC-3 figure as your sizing anchor. Ambient operating range is -20 to +60 °C, with storage and transport range of -50 to +80 °C. The temperature compensation is also rated -20 to +60 °C, meaning the thermal overload characteristic stays within spec across that band without manual adjustment.","metaTitle":"Siemens 3RA2120-1JD24-0BB4 SIRIUS Motor Starter, 10 A AC-3","metaDescription":"Siemens 3RA2120-1JD24-0BB4 SIRIUS direct-on-line starter, 10 A AC-3 at 400 V. Size S0, Class 10, 24 VDC coil. 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","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","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":"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 60 mm busbars","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)","Of The Supplied Busbar Adapter":"8US1251-5NT10","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":"$130.81","priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/64ec4c9baee6092430613c58b2eb9501.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=88953&mlfb=3RA2120-1JD24-0BB4","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA2120-1JD24-0BB4/alternatives.json"},"ai":{"faq":[{"question":"What is the 3RA2120-1JD24-0BB4 rated for in AC-3 duty?","answer":"The same 10 A rating applies at 480 V and 600 V as well. The trip class is Class 10."},{"question":"Does the 3RA2120-1JD24-0BB4 mount on DIN rail or busbars?","answer":"It mounts on 60 mm busbar systems using a snap-on fastening method — not standard DIN rail. The design is specifically for 60 mm busbars, so plan for busbar tap-off, not a DIN-rail backplate."},{"question":"What contactor and link module are supplied with this starter?","answer":"The supplied contactor is a 3RT2024-1BB40 and the supplied link module is a 3RA2921-1BA00. These are factory-matched components that form a coordinated starter assembly."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-1JD24-0BB4","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/3RA2120-1JD24-0BB4 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}