# Semi-pantograph disconnector reference

Canonical URL: https://eloragrid.ai/symbols/semi-pantograph-disconnector-reference
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: SDR
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchyards
Input: Bay primary terminal
Output: Semi-pantograph bus connection

Identifies the documented semi-pantograph construction at its assigned yard connection.

## In plain English

### What this block does

Identifies the documented semi-pantograph construction at its assigned yard connection.

### A simple example

In a switchyard bay, a bus selector can use a different physical construction from a line disconnector. Each device still needs an identified operating mechanism, position indication and interlocking interface. For this reference, the drawing identifies “Bay primary terminal” at the input and “Semi-pantograph bus connection” at the output. Its operating envelope differs from other constructions.

### What the drawings help you do

Start at the named input: Bay primary terminal. Identify its source device or document and the state represented on the drawing. Follow the named output: Semi-pantograph bus connection. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Bay primary terminal
- Output: Semi-pantograph bus connection
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Bay primary terminal → SDR → Semi-pantograph bus connection
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Disconnectors and earthing switches](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/disconnectors-earthing-switches.html)


## What it represents

Identifies the documented semi-pantograph construction at its assigned yard connection. Disconnector and earthing references identify different mechanical constructions and connection duties within a yard. The primary diagram shows which conductors are joined or earthed; the equipment drawing explains how its contacts and supports move.
In a switchyard bay, a bus selector can use a different physical construction from a line disconnector. Each device still needs an identified operating mechanism, position indication and interlocking interface. For this reference, the drawing identifies “Bay primary terminal” at the input and “Semi-pantograph bus connection” at the output. Its operating envelope differs from other constructions.
The construction name does not establish load-breaking capability, short-circuit making duty or operating permission. Verify these properties in the selected equipment data and the station interlocking scheme. 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.

## How to read it

- Start at the named input: Bay primary terminal. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Semi-pantograph bus connection. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Its operating envelope differs from other constructions.
- The construction name does not establish load-breaking capability, short-circuit making duty or operating permission. Verify these properties in the selected equipment data and the station interlocking scheme.

## Information to show or reference

- Label the source and connection reference for bay primary terminal.
- Identify the destination and defined state of semi-pantograph bus connection.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Its operating envelope differs from other constructions.

## Important distinction

Its operating envelope differs from other constructions. 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

- Representation: Functional block
- Installation focus: Switchyards
- Input / boundary: Bay primary terminal
- Output / connection: Semi-pantograph bus connection
- Lookup label: SDR is a library lookup label, not a standard device designation.

## Public references

- [Disconnectors and earthing switches](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/disconnectors-earthing-switches.html) — Siemens Energy. Public technical context for disconnector and earthing applications. Disconnector construction, earthing switches and operating mechanisms. The application text and educational graphic are independently authored; the publisher does not certify this representation.

## 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.