{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RT1945-5AN21","brand":"Siemens","brandSlug":"siemens","productSlug":"3RT1945-5AN21","canonicalUrl":"https://aoctrl.com/siemens/3RT1945-5AN21","factsUrl":"https://aoctrl.com/api/mcp/products/3RT1945-5AN21","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS magnet coil, Size S3, screw terminal, 220 V AC 50/60 Hz, order code 3RT1945-5AN21.","salesMarkdown":"The Siemens 3RT1945-5AN21 is a SIRIUS magnet coil for Size S3 contactors, rated 220 V AC at both 50 Hz and 60 Hz, with a screw terminal connection. It is the replacement coil for the S3 frame — if you are servicing a panel with a failed coil on a SIRIUS 3RT1 contactor in this size, this is the drop-in part. The 220 V AC control supply voltage is common across European 230/400 V line panels; the dual-frequency rating means it works on 50 Hz or 60 Hz mains without a change. Mounts directly onto the SIRIUS Size S3 contactor (3RT103/3RT104 frame). No additional DIN-rail space is consumed; the coil clips onto the contactor magnet stack. For a panel-builder replacing a failed coil, the swap takes under five minutes: remove the four screws on the contactor arc chute, lift the old coil off the magnet yoke, drop the new one in, and re-torque. The at 50 Hz value of 0.8... 1.1 is the operating voltage range as a factor of the rated voltage — so the coil holds in from 176 V to 242 V at 50 Hz. Below 176 V it drops out; above 242 V you risk overheating the winding. The same 0.8 to 1.1 factor applies at 60 Hz, giving a 176–242 V window there as well. This is standard for AC-operated contactor coils and matches the SIRIUS family derating guidelines.","metaTitle":"Siemens 3RT1945-5AN21 SIRIUS Magnet Coil, 220 V AC, 50/60 Hz","metaDescription":"Siemens 3RT1945-5AN21 SIRIUS magnet coil for Size S3 contactors, 220 V AC 50/60 Hz, screw terminal. Phased-out; successor is 3RT2 series. 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":"220 V","at 60 Hz rated value":"220 V","Type Of Voltage Of The Control Supply Voltage":"AC"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$72.01","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=126641&mlfb=3RT1945-5AN21","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RT1945-5AN21/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RT1945-5AN21 and how do I get a price?","answer":"We source this part to order through independent distribution. Submit an RFQ for current availability and pricing — confirmed at quote time."},{"question":"What is the at 50 Hz rating on 3RT1945-5AN21?","answer":"The at 50 Hz value is 0.8... 1.1, meaning the coil operates reliably between 176 V and 242 V at 50 Hz. The same range applies at 60 Hz."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RT1945-5AN21","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/3RT1945-5AN21 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}}