{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1944-5AL21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1944-5AL21","canonicalUrl":"https://aoctrl.com/siemens/3RT1944-5AL21","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5AL21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS, magnet coil, 3RT1944-5AL21, 230 V AC 50/60 Hz, screw terminal, Size S3.","salesMarkdown":"The Siemens 3RT1944-5AL21 is a SIRIUS magnet coil — the replaceable solenoid that pulls in the contactor armature. It's sized for Size S3 contactors and terminates via screw terminals. The 0.8... 1.1 figure at 50 Hz is the operating voltage range as a factor of the rated coil voltage (230 V). That means the coil reliably picks up and holds between roughly 184 V and 253 V AC — a ±15% tolerance that covers typical line sags without dropping out. The same 230 V rating applies at 60 Hz, so it's a straight swap across 50/60 Hz regions. ## Deployment context The screw terminals match existing panel wiring practices — no crimp-tool change needed for the control circuit.","metaTitle":"Siemens 3RT1944-5AL21 SIRIUS Magnet Coil, 230 V AC, 50/60 Hz","metaDescription":"Siemens SIRIUS 3RT1944-5AL21 magnet coil for Size S3 contactors, 230 V AC 50/60 Hz, screw terminal. Phased-out; successor is SIRIUS 3RT2. Sourced to order.","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":"230 V","at 60 Hz rated value":"230 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=65608&mlfb=3RT1944-5AL21","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5AL21/alternatives.json"},"ai":{"faq":[{"question":"What replaces the 3RT1944-5AL21?","answer":"The manufacturer's stated successor is the SIRIUS 3RT2 series. For a direct coil replacement, verify the 3RT2 coil order code matches your contactor frame size and coil voltage."},{"question":"What is the coil voltage and frequency rating?","answer":"Rated 230 V AC at both 50 Hz and 60 Hz. The operating range is 0.8 to 1.1 times the rated voltage at 50 Hz."},{"question":"Will the 3RT1944-5AL21 fit a panel built around the 3RT1023-1AL20 contactor?","answer":"No — the 3RT1944-5AL21 is a magnet coil for Size S3 contactors, while the 3RT1023-1AL20 is a Size S0 power contactor. The coil form factor and mounting differ between frame sizes."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1944-5AL21","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/3RT1944-5AL21 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}}