{"schemaVersion":1,"slug":"31-separate-excitation-device","name":"Separate excitation device","kind":"function","abbreviation":"31","aliases":["separate excitation","excitation connection device","ANSI 31","IEEE device 31"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEEE / ANSI"],"summary":"Connects or controls a separately supplied excitation arrangement for a machine.","description":["Connects or controls a separately supplied excitation arrangement for a machine.","In a drafting package, connect this reference to the separate excitation supply and machine field connection. The associated drawing should trace the excitation switching command and sequence references; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.","This designation is useful when reading machine and legacy control drawings. Retain the documented function on an existing drawing and consult the original equipment manual before assigning it to a new design."],"readingNotes":["Identify the separate excitation supply and machine field connection.","Trace the excitation switching command and sequence references."],"drawingChecklist":["Label the separate excitation supply and machine field connection.","Cross-reference the excitation switching command and sequence references.","Identify the device tag, manual revision and logic drawing that define this implementation."],"distinction":"This specialist machine-control reference should be interpreted with the excitation drawing; device 41 identifies a field breaker.","facts":[{"label":"ANSI / IEEE function number","value":"31"},{"label":"Drawing context","value":"The separate excitation supply and machine field connection"},{"label":"Application scope","value":"Specialist or legacy machine-control use; interpret with the equipment legend."}],"references":[{"sourceId":"pub-function-sel-numbers","relevance":"Public manufacturer number/name association. Drafting explanations are independently written."},{"sourceId":"ieee-functions","relevance":"Normative device-number publication; exact edition wording and compliance require the licensed standard."}],"related":["generator","52-ac-circuit-breaker"],"artwork":"pub-function-box","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/protection-functions/31-separate-excitation-device","illustration":{"url":"https://eloragrid.ai/library/illustrations/31-separate-excitation-device.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-function-sel-numbers","title":"ANSI device-number and suffix reference table","publisher":"Schweitzer Engineering Laboratories","url":"https://selinc.com/pt/products/tables/ansi/","type":"manufacturer","scope":"Public Portuguese-language base-number and application-suffix table. Used to cross-check public number associations. Application-specific and historical labels need the selected drawing legend; this table is not a substitute for the licensed IEEE standard.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public manufacturer number/name association. Drafting explanations are independently written."},{"id":"ieee-functions","title":"IEEE C37.2-2022: power-system device function numbers","publisher":"IEEE","url":"https://ieeexplore.ieee.org/document/9984140","type":"standard","scope":"Device function numbers, acronyms and contact designations. The full publication may require access through IEEE.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Normative device-number publication; exact edition wording and compliance require the licensed standard."}]}