CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic
Functional block · MMI
Mechanism maintenance-alarm interface
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.
Browse this installation focusIn plain English
What this block does
Brings a documented mechanism maintenance indication into the station alarm system.
A simple example
In a switchgear panel, a charging motor replenishes the mechanism after an operation. Supervisory contacts let the controller report an incomplete charge or repeated charging demand before an operator requests another operation. For this reference, the drawing identifies “Mechanism monitoring output” at the input and “Maintenance alarm” at the output. An alarm is a maintenance input rather than a diagnosis.
What the drawings help you do
Start at the named input: Mechanism monitoring output. Identify its source device or document and the state represented on the drawing. Follow the named output: Maintenance alarm. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Mechanism monitoring output
- Output
- Maintenance 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 · MMI
What it represents
Brings a documented mechanism maintenance indication into the station alarm system. A stored-energy breaker mechanism has charging, release, indication and supervision functions. Motor supply, stored spring energy and the ability to complete an opening operation are separate drawing concerns.
In a switchgear panel, a charging motor replenishes the mechanism after an operation. Supervisory contacts let the controller report an incomplete charge or repeated charging demand before an operator requests another operation. For this reference, the drawing identifies “Mechanism monitoring output” at the input and “Maintenance alarm” at the output. An alarm is a maintenance input rather than a diagnosis.
Show the individual contacts and the relevant motor or release circuit. Supply voltage, charging time, operating duty and permissible alarms must follow the chosen mechanism documentation. 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: Mechanism monitoring output. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Maintenance alarm. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- An alarm is a maintenance input rather than a diagnosis.
- Show the individual contacts and the relevant motor or release circuit. Supply voltage, charging time, operating duty and permissible alarms must follow the chosen mechanism documentation.
Information to show or reference
- Label the source and connection reference for mechanism monitoring output.
- Identify the destination and defined state of maintenance alarm.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: An alarm is a maintenance input rather than a diagnosis.
A distinction that matters
An alarm is a maintenance input rather than a diagnosis. 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 stored-energy mechanism supervision. 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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