{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1944-5AH21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1944-5AH21","canonicalUrl":"https://aoctrl.com/siemens/3RT1944-5AH21","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5AH21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RT1944-5AH21 magnet coil, Size S3, screw terminal, 48 V AC 50/60 Hz, for SIRIUS contactors.","salesMarkdown":"The Siemens 3RT1944-5AH21 is a SIRIUS magnet coil designed for Size S3 contactors — the replacement coil that snaps into the contactor's coil terminals when the original fails or the control voltage needs changing. It's a screw-terminal coil rated for 48 V AC at both 50 Hz and 60 Hz, drawing 0.8 to 1.1 A at 50 Hz. The AC control voltage type means it's intended for conventional line-frequency control circuits, not DC or electronic coil drives. ## Lifecycle reality — phased out with a successor This coil is a phased-out product. The manufacturer lists the successor as the SIRIUS 3RT2 series — the newer generation of contactors and their coils. For a BOM that's frozen on the 3RT1 platform, this 3RT1944-5AH21 is the correct drop-in replacement coil. For new designs or panel refreshes, the 3RT2 platform is the forward path. The coil mounts onto the Size S3 contactor's coil terminals via screw connections — no DIN-rail space consumed beyond the contactor itself. Verify the contactor's coil terminal arrangement matches the screw-terminal format before ordering.","metaTitle":"Siemens 3RT1944-5AH21 SIRIUS Magnet Coil, 48 V AC, Size S3","metaDescription":"Siemens 3RT1944-5AH21 SIRIUS magnet coil for Size S3 contactors. 48 V AC, 50/60 Hz, screw terminal. Phased-out product; successor is SIRIUS 3RT2 series. Sourced to order against RF","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"at 50 Hz":"0.8 ... 1.1","lifecycle_stage":"current","Product Brand Name":"SIRIUS","Product Designation":"Magnet coil","at 50 Hz rated value":"48 V","at 60 Hz rated value":"48 V","Type Of Voltage Of The Control Supply Voltage":"AC"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=88151&mlfb=3RT1944-5AH21","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5AH21/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RT1944-5AH21?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — no stock or lead-time figures are published for this phased-out item."},{"question":"What is the at 50 Hz rating for 3RT1944-5AH21?","answer":"The coil draws 0.8 to 1.1 A at 50 Hz with a rated control supply voltage of 48 V AC."},{"question":"Will 3RT1944-5AH21 drop into a panel specified around 3RT1017-1AD02?","answer":"No — the 3RT1017-1AD02 is a Size S00 power contactor with a different coil voltage (42 V AC) and a physically smaller frame. The 3RT1944-5AH21 is a Size S3 coil; it will not fit the S00 contactor's coil cavity without mechanical modification."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1944-5AH21","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/3RT1944-5AH21 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}}