CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic
Functional block · SCP
Spring-charged closing permissive
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
Allows the closing path only when the stored-energy mechanism reports ready.
A simple example
In a switchgear bus-coupler panel, a close request is checked against position, mechanism readiness and the selected live-bus or dead-bus conditions before the closing circuit is enabled. For this reference, the drawing identifies “Spring-ready contact” at the input and “Closing permission” at the output. Mechanical readiness is not a synchronism check.
What the drawings help you do
Start at the named input: Spring-ready contact. Identify its source device or document and the state represented on the drawing. Follow the named output: Closing permission. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Spring-ready contact
- Output
- Closing permission
- 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 · SCP
What it represents
Allows the closing path only when the stored-energy mechanism reports ready. A closing circuit combines an operator or automatic request with the conditions that allow the breaker to close. The closing coil releases stored mechanism energy where that construction is used; it is different from the spring-charging motor.
In a switchgear bus-coupler panel, a close request is checked against position, mechanism readiness and the selected live-bus or dead-bus conditions before the closing circuit is enabled. For this reference, the drawing identifies “Spring-ready contact” at the input and “Closing permission” at the output. Mechanical readiness is not a synchronism check.
Follow request, permission and final coil output as separate signals. A permissive diagram must say which conditions block closing and what happens if a feedback signal becomes unavailable. 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: Spring-ready contact. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Closing permission. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Mechanical readiness is not a synchronism check.
- Follow request, permission and final coil output as separate signals. A permissive diagram must say which conditions block closing and what happens if a feedback signal becomes unavailable.
Information to show or reference
- Label the source and connection reference for spring-ready contact.
- Identify the destination and defined state of closing permission.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Mechanical readiness is not a synchronism check.
A distinction that matters
Mechanical readiness is not a synchronism check. 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 closing controls. 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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