{"schemaVersion":1,"slug":"tap-changer-lower-limit-inhibit","name":"Tap-changer lower-limit inhibit","kind":"symbol","abbreviation":"TLI","aliases":["Transformer regulation and cooling control","substations Transformer regulation and cooling control","substations","Substations","Lower tap limit contact","Lower-command restraint"],"category":"measurement-protection","drawingTypes":["Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Blocks further movement in the assigned direction at the documented lower limit.","description":["Blocks further movement in the assigned direction at the documented lower limit. Transformer regulation changes the selected winding connection to influence voltage, while cooling control manages the installed fans and pumps. Commands, mechanical position and measured results belong to different parts of the diagram.","In a substation, a voltage regulator can request a tap change and check the resulting tap-position feedback. A separate controller stages cooling equipment according to the transformer manufacturer's defined conditions. For this reference, the drawing identifies “Lower tap limit contact” at the input and “Lower-command restraint” at the output. Tap numbering is not universal between transformers.","Keep tap-change permission, limit contacts, movement indication and measured voltage distinct. Actual tap positions, time delays, cooling ratings and allowable parallel operation require the selected transformer control design. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation."],"readingNotes":["Start at the named input: Lower tap limit contact. Identify its source device or document and the state represented on the drawing.","Follow the named output: Lower-command restraint. Cross-reference its destination and separate the command from confirmation that the equipment responded.","Tap numbering is not universal between transformers.","Keep tap-change permission, limit contacts, movement indication and measured voltage distinct. Actual tap positions, time delays, cooling ratings and allowable parallel operation require the selected transformer control design."],"drawingChecklist":["Label the source and connection reference for lower tap limit contact.","Identify the destination and defined state of lower-command restraint.","Record the equipment or control-document revision supporting this functional block.","Check this application limit in the project design: Tap numbering is not universal between transformers."],"distinction":"Tap numbering is not universal between transformers. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.","facts":[{"label":"Representation","value":"Functional block"},{"label":"Installation focus","value":"Substations"},{"label":"Input / boundary","value":"Lower tap limit contact"},{"label":"Output / connection","value":"Lower-command restraint"},{"label":"Lookup label","value":"TLI is a library lookup label, not a standard device designation."}],"references":[{"sourceId":"pi26-transformer-control","relevance":"Public technical context for transformer regulation and cooling control. Transformer temperature, cooling, tap changing and parallel operation. The application text and educational graphic are independently authored; the publisher does not certify this representation."}],"related":["adjustable-ratio-transformer","winding-temperature-indicator","tap-position-coded-input-decoder"],"artwork":"pi26-tap-changer-lower-limit-inhibit","publishedOn":"2026-11-03","updatedOn":"2026-11-03","provenance":"independent-public-research","representation":{"type":"functional-block","focus":"substations","family":"transformer-regulation","input":"Lower tap limit contact","output":"Lower-command restraint"},"plainEnglish":{"title":"What this block does","introduction":"Blocks further movement in the assigned direction at the documented lower limit.","example":"In a substation, a voltage regulator can request a tap change and check the resulting tap-position feedback. A separate controller stages cooling equipment according to the transformer manufacturer's defined conditions. For this reference, the drawing identifies “Lower tap limit contact” at the input and “Lower-command restraint” at the output. Tap numbering is not universal between transformers.","drawings":"Start at the named input: Lower tap limit contact. Identify its source device or document and the state represented on the drawing. Follow the named output: Lower-command restraint. Cross-reference its destination and separate the command from confirmation that the equipment responded.","terms":[{"name":"Input","meaning":"Lower tap limit contact"},{"name":"Output","meaning":"Lower-command restraint"},{"name":"Application reference","meaning":"An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections."}],"diagram":"flow","steps":["Lower tap limit contact","TLI","Lower-command restraint"],"caption":"A reading guide. The entry's original illustration and input/output facts describe this application.","sources":[{"label":"SEL-2414 transformer monitor","url":"https://selinc.com/products/2414/"}],"profileId":"power-installation-transformer-regulation"},"url":"https://eloragrid.ai/symbols/tap-changer-lower-limit-inhibit","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/tap-changer-lower-limit-inhibit.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pi26-transformer-control","publisher":"SEL","title":"SEL-2414 transformer monitor","url":"https://selinc.com/products/2414/","scope":"Transformer temperature, cooling, tap changing and parallel operation.","type":"manufacturer","checkedOn":"2026-11-03","reuse":"link-only","relevance":"Public technical context for transformer regulation and cooling control. Transformer temperature, cooling, tap changing and parallel operation. The application text and educational graphic are independently authored; the publisher does not certify this representation."}]}