# Circuit-breaker trip-free mechanism reference

Canonical URL: https://eloragrid.ai/symbols/circuit-breaker-trip-free-mechanism-reference
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: CTMR
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Trip and close mechanism inputs
Output: Trip-free opening action

Identifies the operating property that permits opening despite a sustained closing request.

## In plain English

### What this block does

Identifies the operating property that permits opening despite a sustained closing request.

### 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 “Trip and close mechanism inputs” at the input and “Trip-free opening action” at the output. The mechanism property is confirmed by equipment documentation.

### What the drawings help you do

Start at the named input: Trip and close mechanism inputs. Identify its source device or document and the state represented on the drawing. Follow the named output: Trip-free opening action. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Trip and close mechanism inputs
- Output: Trip-free opening action
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Trip and close mechanism inputs → CTMR → Trip-free opening action
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

Identifies the operating property that permits opening despite a sustained closing request. 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 “Trip and close mechanism inputs” at the input and “Trip-free opening action” at the output. The mechanism property is confirmed by equipment documentation.
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: Trip and close mechanism inputs. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Trip-free opening action. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The mechanism property is confirmed by equipment documentation.
- 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 trip and close mechanism inputs.
- Identify the destination and defined state of trip-free opening action.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The mechanism property is confirmed by equipment documentation.

## Important distinction

The mechanism property is confirmed by equipment documentation. 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: Trip and close mechanism inputs
- Output / connection: Trip-free opening action
- Lookup label: CTMR 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.