{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4BH27-0AP0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4BH27-0AP0","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4BH27-0AP0","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BH27-0AP0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4BH27-0AP0 direct online motor starter, size S0, 7.5 kW at 400 V, 690 V AC-3 max, Class 10, spring-loaded terminals, snap-on 60 mm busbar.","salesMarkdown":"The 3RA2120-4BH27-0AP0: It ships as a pre-matched assembly: the supplied contactor is 3RT2027-2AP00, the circuit-breaker is 3RV2021-4BA20, plus the link module 3RA2921-2AA00 and busbar adapter 8US1251-5NT11 — the BOM is coordinated for the 7.5 kW rating, so you don't need to size each component separately. The overload release is thermal bimetallic (Trip Class 10), and the short-circuit trip is magnetic — standard protection for motor starting duty where the inrush lasts under 10 seconds. ## Snap-on busbar mounting and clearance envelope This starter snaps directly onto 60 mm busbar systems — no DIN rail adapter needed — and is designed specifically for that busbar pitch. The enclosure measures 165 mm deep, 45 mm wide, and 260 mm high. Clearance requirements: 50 mm above, 20 mm forward, 0 mm behind, 10 mm below, and 20 mm at the sides — these are the minimum gaps for ventilation and wiring access. Mounting position must be vertical — the bimetallic overload relies on natural convection for accurate thermal replication, so horizontal mounting shifts the trip curve. ## Spring-loaded terminals and environmental limits Both the main current circuit and the auxiliary/control circuit use spring-loaded terminals — no screw torque to verify, just strip and push in solid or ferruled stranded wire. Operating temperature range is -20 to +60 °C, with storage and transport limits from -50 to +80 °C — the starter can sit in an unheated warehouse through winter and still commission in a warm cabinet. The substance prohibitance date of 10/01/2009 confirms RoHS compliance for the European market.","metaTitle":"Siemens 3RA2120-4BH27-0AP0 SIRIUS Motor Starter","metaDescription":"Siemens 3RA2120-4BH27-0AP0 SIRIUS direct online starter, size S0, 7.5 kW at 400 V AC-3, Class 10, spring terminals, snap-on 60 mm busbar.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"165 mm","Width":"45 mm","title":"3RA2120-4BH27-0AP0","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":"690 V","description":"Load feeder fuseless, Direct-on-line starting 400 V AC, Size S0 13...20 A 230 V AC 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)","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 400 V rated value":"7 500 W","at 50 Hz rated value":"230 ... 230 V","Design Of The Product":"for 60 mm busbars","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","Of The Supplied Contactor":"3RT2027-2AP00","Of The Supplied Link Module":"3RA2921-2AA00","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","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":"3RV2021-4BA20","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","apparent holding power of magnet coil at AC":"9.8 VA","protocol is supported AS-Interface protocol":"No","with high demand rate according to SN 31920":"73 %","shock resistance according to IEC 60068-2-27":"6g / 11 ms","Type Of Voltage Of The Control Supply Voltage":"AC","at 400 V according to IEC 60947-4-1 rated value":"150 000 A","operational current at AC-3 at 400 V rated value":"15.5 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":"13 ... 20 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/30f80ca73dcd1eb504ee1c17474950bf.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=91360&mlfb=3RA2120-4BH27-0AP0"},"ai":{"faq":[{"question":"What are the key ratings for 3RA2120-4BH27-0AP0?","answer":"Trip Class 10 with thermal bimetallic overload and magnetic short-circuit trip."},{"question":"What sub-assemblies are included with 3RA2120-4BH27-0AP0?","answer":"The starter ships with contactor 3RT2027-2AP00, circuit-breaker 3RV2021-4BA20, link module 3RA2921-2AA00, and busbar adapter 8US1251-5NT11 — all pre-matched for the 7.5 kW rating."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4BH27-0AP0","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/3RA2120-4BH27-0AP0 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}}