{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RA2120-4DE27-0AP0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RA2120-4DE27-0AP0","canonicalUrl":"https://aoctrl.com/siemens/3RA2120-4DE27-0AP0","factsUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4DE27-0AP0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RA2120-4DE27-0AP0 direct online motor starter, S0 size, 25 A AC-3 at 400 V, Class 10 trip, spring-loaded terminals, 45 mm width, 243 mm height, 107 mm depth.","salesMarkdown":"## Panel fit and mounting constraints The 3RA2120-4DE27-0AP0 occupies a 45 mm wide footprint on 35 mm DIN rail, with a height of 243 mm and depth of 107 mm — the S0 frame size dictates the panel cut-out and busbar spacing. Mounting is vertical only, secured by screw and snap-on onto the DIN rail. Clearance requirements: 50 mm above, 20 mm forward, 10 mm below, 20 mm at the sides, and 0 mm backward — plan the enclosure layout around these ventilation and wiring access zones. ## Motor starting duty and trip coordination The supplied contactor is a 3RT2027-2AP00, and the link module is 3RA2921-2AA00 — these are pre-assembled and tested as a matched set. ## Sourcing and lifecycle position For BOM planning, the S0 frame size and 45 mm width are consistent across the SIRIUS 3RA2 series, so a panel layout using this starter can be replicated with other S0-rated units without re-spacing the DIN rail.","metaTitle":"Siemens 3RA2120-4DE27-0AP0 SIRIUS Motor Starter, 25A AC-3","metaDescription":"Siemens 3RA2120-4DE27-0AP0 SIRIUS direct online motor starter, 25A AC-3 at 400V, Class 10 trip, S0 size. Active production, quoted to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Starters"],"specifications":{"Depth":"107 mm","Width":"45 mm","Height":"243 mm","Upwards":"50 mm","Forwards":"20 mm","at 50 Hz":"0.25","Backwards":"0 mm","Downwards":"10 mm","Trip Class":"CLASS 10","At The Side":"20 mm","Rated Value":"690 V","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":"3 hp","at 400 V rated value":"11 000 kW","at 480 V rated value":"25 A","at 50 Hz rated value":"230 ... 230 V","at 600 V rated value":"25 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":"2 hp","at 200/208 V rated value":"7.5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"20 hp","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","at AC-3 at 400 V rated value":"25 A","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"25 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":"3RV2021-4DA20","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":"9.8 W","Surge Voltage Resistance Rated Value":"6 kV","at AC in hot operating state per pole":"5.8 W","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 %","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":"AC","at 400 V according to IEC 60947-4-1 rated value":"150 000 A","Inductive Power Factor With The Holding Power Of The Coil":"0.25","Mechanical Service Life (Operating Cycles) Of Contactor Typical":"10 000 000","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"325 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":"18 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/30d6960c99035aa66dc08f47f5a85fc3.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=415902&mlfb=3RA2120-4DE27-0AP0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RA2120-4DE27-0AP0/alternatives.json"},"ai":{"faq":[{"question":"What is the AC-3 rating at 400 V for this motor starter?","answer":"The 3RA2120-4DE27-0AP0 is rated 25 A at AC-3 duty at 400 V, which corresponds to 11 kW motor capacity at 400 V. This is the key rating for sizing motor loads."},{"question":"What clearance is needed around this starter in the panel?","answer":"Minimum clearances: 50 mm above, 20 mm forward, 10 mm below, 20 mm at the sides, and 0 mm backward. These ensure adequate ventilation for the Class 10 trip curve and access to the spring-loaded terminals."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RA2120-4DE27-0AP0","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/3RA2120-4DE27-0AP0 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}}