# Open-delta winding connection

Canonical URL: https://eloragrid.ai/symbols/open-delta-winding-connection
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: OPEN D
Drawing use: SLD, Schematic
Reference families: IEC, Manufacturer

An open-delta arrangement uses an incomplete delta connection for a specified transformer or measurement purpose.

## What it represents

An open-delta arrangement uses an incomplete delta connection for a specified transformer or measurement purpose. The absent winding or open connection must be visible rather than interpreted as an accidental drawing omission.

## How to read it

- Identify the actual application and its documented winding arrangement.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.

## Information to show or reference

- Show open portion
- Name connected terminals
- Reference applicable rating or measurement scheme

## Important distinction

Open delta and broken-delta residual-voltage circuits describe different application contexts; the drawing must say which is intended.

## Facts

- Drawing role: Three-phase winding
- Representation scope: Functional concept; not an official standard graphic or a product footprint
- Identifier status: 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.

## Public references

- [AutoCAD Electrical: Winding arrangements and AC/DC indications](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3F5A759D-872A-4990-8AAE-7CCAFBBBD4C5.htm) — Autodesk. Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.