{"schemaVersion":1,"slug":"differential-voltmeter","name":"Differential voltmeter","kind":"symbol","abbreviation":"DELTA V","aliases":["HVM1P7","VVM1P7"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"A differential voltmeter indicates a difference between documented voltage inputs.","description":["A differential voltmeter indicates a difference between documented voltage inputs. Its reference and compared circuits must be identifiable so the indicated difference has a defined meaning."],"readingNotes":["Verify the input connection arrangement against the actual instrument diagram.","The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation."],"drawingChecklist":["Identify both compared inputs","State polarity/reference","Reference measurement range"],"distinction":"A differential voltage indicator is different from a transformer differential protection function.","facts":[{"label":"Drawing role","value":"Indicated quantity"},{"label":"Representation scope","value":"Functional concept; not an official standard graphic or a product footprint"},{"label":"Public vendor block reference","value":"HVM1P7, VVM1P7 (Autodesk identifiers; not IEC symbol numbers)"},{"label":"Identifier status","value":"The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name."}],"references":[{"sourceId":"pub-symbol-instrumentation","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}],"related":["current-transformer","voltage-transformer"],"artwork":"edu-differential-voltmeter","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/differential-voltmeter","illustration":{"url":"https://eloragrid.ai/library/illustrations/differential-voltmeter.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-instrumentation","title":"AutoCAD Electrical: Instrumentation and sensors","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-773A36C3-44C6-43EB-9BD0-E0297816B9B2.htm","type":"cad-reference","scope":"Public vendor catalogue naming and functional variants. Vendor block names are not IEC identifiers. Linked for reference; no graphics or CAD files are redistributed.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}]}