{"schemaVersion":1,"slug":"56-field-application-relay","name":"Field application relay","kind":"function","abbreviation":"56","aliases":["field application","field apply relay","ANSI 56","IEEE device 56"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEEE / ANSI"],"summary":"Initiates application of excitation at the appropriate step of a machine starting sequence.","description":["Initiates application of excitation at the appropriate step of a machine starting sequence.","In a drafting package, connect this reference to the speed/sequence permission and excitation supply. The associated drawing should trace the field application command and field switching device; 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 speed/sequence permission and excitation supply.","Trace the field application command and field switching device."],"drawingChecklist":["Label the speed/sequence permission and excitation supply.","Cross-reference the field application command and field switching device.","Identify the device tag, manual revision and logic drawing that define this implementation."],"distinction":"Field application is a sequence action; loss-of-excitation 40 supervises abnormal excitation after or during operation.","facts":[{"label":"ANSI / IEEE function number","value":"56"},{"label":"Drawing context","value":"The speed/sequence permission and excitation supply"},{"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":["motor","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/56-field-application-relay","illustration":{"url":"https://eloragrid.ai/library/illustrations/56-field-application-relay.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."}]}