# Capacitor-trip operating interface

Canonical URL: https://eloragrid.ai/symbols/capacitor-trip-operating-interface
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: COI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Charged capacitor unit
Output: Trip operating energy

Uses stored electrical energy in a documented capacitor-trip unit to support an opening operation.

## In plain English

### What this block does

Uses stored electrical energy in a documented capacitor-trip unit to support an opening operation.

### A simple example

In a medium-voltage switchgear drawing, the operating reference helps the reader distinguish the interrupting device from its isolation, earthing and auxiliary-control interfaces. For this reference, the drawing identifies “Charged capacitor unit” at the input and “Trip operating energy” at the output. Stored charge requires its own supervision and handling rules.

### What the drawings help you do

Start at the named input: Charged capacitor unit. Identify its source device or document and the state represented on the drawing. Follow the named output: Trip operating energy. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Charged capacitor unit
- Output: Trip operating energy
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Charged capacitor unit → COI → Trip operating energy
A reading guide. The entry's original illustration and input/output facts describe this application.

- [High-voltage circuit breakers](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/circuit-breakers.html)


## What it represents

Uses stored electrical energy in a documented capacitor-trip unit to support an opening operation. A switching-device operating reference adds the specific mechanism or duty context needed to interpret its place in a power circuit. The same basic switching outline can serve different equipment constructions, so the added description must remain attached to its device tag.
In a medium-voltage switchgear drawing, the operating reference helps the reader distinguish the interrupting device from its isolation, earthing and auxiliary-control interfaces. For this reference, the drawing identifies “Charged capacitor unit” at the input and “Trip operating energy” at the output. Stored charge requires its own supervision and handling rules.
Use the device schedule for its actual construction, operating duty and ratings. These original functional illustrations describe the named role and do not certify a standard glyph or product footprint. 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: Charged capacitor unit. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Trip operating energy. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Stored charge requires its own supervision and handling rules.
- Use the device schedule for its actual construction, operating duty and ratings. These original functional illustrations describe the named role and do not certify a standard glyph or product footprint.

## Information to show or reference

- Label the source and connection reference for charged capacitor unit.
- Identify the destination and defined state of trip operating energy.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Stored charge requires its own supervision and handling rules.

## Important distinction

Stored charge requires its own supervision and handling rules. 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: Switchgear
- Input / boundary: Charged capacitor unit
- Output / connection: Trip operating energy
- Lookup label: COI is a library lookup label, not a standard device designation.

## Public references

- [High-voltage circuit breakers](https://www.siemens-energy.com/global/en/home/products-services/product-offerings/circuit-breakers.html) — Siemens Energy. Public technical context for switching-device operating references. Circuit-breaker construction and interruption families. 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.