{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1944-5BB42","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1944-5BB42","canonicalUrl":"https://aoctrl.com/siemens/3RT1944-5BB42","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5BB42","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS, magnet coil for Size S3 contactors, 24 V DC, spring-loaded connection technology, order code 3RT1944-5BB42.","salesMarkdown":"The Siemens SIRIUS 3RT1944-5BB42 is a magnet coil for Size S3 contactors, rated 24 V DC and terminated with spring-loaded connection technology. It is the coil that pulls in and holds the contactor armature — the part that actually switches the load. The SIRIUS platform is Siemens' modular contactor and motor-starter family, so this coil mounts directly onto the S3 frame, which covers the 38–65 A motor current range in AC-3 duty. ## Sourcing reality — phased out, but replaceable This part is flagged as a phased-out product. Siemens' official successor is the SIRIUS 3RT2 series, which uses the same Size S3 frame and 24 V DC coil voltage. ## What the 24 V DC rating means for fit The 24 V DC coil is the control voltage — this is what the PLC output or control relay must supply to energize the contactor. DC coils hold in with continuous DC, unlike AC coils that hum and require a different latching characteristic. Size S3 means the coil physically fits SIRIUS contactors in that frame class; verify the mating contactor's order code includes the S3 designation.","metaTitle":"Siemens 3RT1944-5BB42 SIRIUS Magnet Coil, 24 V DC, Size S3","metaDescription":"Siemens SIRIUS 3RT1944-5BB42 magnet coil for Size S3 contactors. 24 V DC, spring-loaded connection. Phased-out; official successor is the 3RT2 series. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"lifecycle_stage":"current","Product Brand Name":"SIRIUS","1 at DC rated value":"24 V","Product Designation":"Magnet coil","Type Of Voltage Of The Control Supply Voltage":"DC"}},"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=197628&mlfb=3RT1944-5BB42","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1944-5BB42/alternatives.json"},"ai":{"faq":[{"question":"Will this coil fit a 3RT1015-1BB42 contactor?","answer":"No — the 3RT1944-5BB42 is a Size S3 coil, while the 3RT1015-1BB42 is a Size S00 contactor. The frame sizes are physically different; the S3 coil will not mount on an S00 contactor. Stick with the correct frame-size coil for each contactor."},{"question":"What compliance documentation is available for this part?","answer":"The evidence does not list specific compliance certificates. As a Siemens SIRIUS component, it is typically supplied with CE marking and RoHS compliance, but the exact documentation set (UL, CSA, REACH) should be confirmed at order placement."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1944-5BB42","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/3RT1944-5BB42 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}}