CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic
Functional block · BPA
Breaker position-discrepancy alarm
Functional block · Switchgear
An independently authored application reference. The drawing shows the named function or circuit relationship; use the project legend and selected equipment documentation for its drafting form and connections.
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What this block does
Reports an auxiliary-contact combination that persists beyond the allowed transition interval.
A simple example
In a switchgear control schematic, the bay controller compares independent status contacts before displaying a position or allowing another operation. The signal labels explain which physical state each contact represents. For this reference, the drawing identifies “Auxiliary-contact disagreement” at the input and “Position-discrepancy alarm” at the output. The transition allowance is project-specific.
What the drawings help you do
Start at the named input: Auxiliary-contact disagreement. Identify its source device or document and the state represented on the drawing. Follow the named output: Position-discrepancy alarm. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Auxiliary-contact disagreement
- Output
- Position-discrepancy alarm
- Application reference
- An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.
Read the source: Masterclad medium-voltage switchgear: circuit-breaker section interlocks
Schematic · BPA
What it represents
Reports an auxiliary-contact combination that persists beyond the allowed transition interval. Breaker status indications describe the operating mechanism, the removable truck or the health of a supporting system. These signals are related but are not interchangeable: an open breaker can still have its truck connected to live bus contacts.
In a switchgear control schematic, the bay controller compares independent status contacts before displaying a position or allowing another operation. The signal labels explain which physical state each contact represents. For this reference, the drawing identifies “Auxiliary-contact disagreement” at the input and “Position-discrepancy alarm” at the output. The transition allowance is project-specific.
Keep contact reference conditions, terminal numbers and interpretation logic together. Distinguish a mechanically operated indication from a measured current or voltage condition. 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: Auxiliary-contact disagreement. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Position-discrepancy alarm. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The transition allowance is project-specific.
- Keep contact reference conditions, terminal numbers and interpretation logic together. Distinguish a mechanically operated indication from a measured current or voltage condition.
Information to show or reference
- Label the source and connection reference for auxiliary-contact disagreement.
- Identify the destination and defined state of position-discrepancy alarm.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The transition allowance is project-specific.
A distinction that matters
The transition allowance is project-specific. 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.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Masterclad medium-voltage switchgear: circuit-breaker section interlocks
Public technical context for breaker position and status interfaces. Breaker control, mechanism, position contacts, racking interlocks and test interfaces. The application text and educational graphic are independently authored; the publisher does not certify this representation.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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