{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4BE26-0BB4","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4BE26-0BB4","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4BE26-0BB4","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4BE26-0BB4","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4BE26-0BB4 direct online starter, size S0, 20 A AC-3 at 400 V, Trip Class 10, 24 V DC coil, spring-loaded terminals, screw and snap-on 35 mm DIN rail.","salesMarkdown":"## BOM fit — AC-3 motor rating and trip class The 3RA2120-4BE26-0BB4: That means it switches squirrel-cage motors up to 20 A under full-load starting conditions without welding the main contacts. If the load has a long acceleration ramp (high-inertia fans), a Class 20 or 30 starter would be needed. The horsepower equivalents span 1.5 hp at 110/120 V up to 20 A at 480/600 V, so it covers a range of common North American and IEC motor frames. Match the FLA on the motor nameplate to the 20 A ceiling. ## Integrated assembly — contactor and link module included The starter ships with the contactor 3RT2026-2BB40 and the link module 3RA2921-2AA00 already matched — no separate sizing of contactor and overload relay. The size S0 circuit-breaker interface is built in. Main circuit connections use spring-loaded terminals, so you land the power wires without torquing screws — useful in high-density panels where screw access is tight. The control coil is 24 V DC, the standard for PLC-driven panels. ## Mounting and clearances Mounts vertically on 35 mm DIN rail with a screw and snap-on fastening. The footprint is 45 mm wide by 243 mm tall by 107 mm deep — it fits a standard S0 feeder slot. Required clearances: 50 mm above, 20 mm below, 20 mm to the sides, 20 mm forward, zero backward. Plan the enclosure depth to leave at least 107 mm plus wiring space behind the door.","metaTitle":"Siemens 3RA2120-4BE26-0BB4 SIRIUS direct starter, 20 A AC-3","metaDescription":"Siemens SIRIUS 3RA2120-4BE26-0BB4 direct online starter, size S0, 20 A AC-3 at 400 V, Trip Class 10, 24 V DC coil, spring 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":"3RA2120-4BE26-0BB4","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 13...20 A 24 V DC Spring-type terminal for installation on standard mounting rail Type of coordination 1, 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":"1","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":"7 500 kW","at 480 V rated value":"20 A","at 600 V rated value":"20 A","Design Of The Product":"for standard rail or screw mounting","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-20 ... +60 °C","at 110/120 V rated value":"1.5 hp","at 200/208 V rated value":"5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"15 hp","Of The Supplied Contactor":"3RT2026-2BB40","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":"20 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"20 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":"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 %","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":"5.4 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":"260 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":"13 ... 20 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/8e649a4674b7163feb4ec0a3fcff260f.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=140914&mlfb=3RA2120-4BE26-0BB4"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4BE26-0BB4","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/3RA2120-4BE26-0BB4 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}}