Coil
Relay coil
The operating element associated with a relay and its separately drawn contacts.
Schematic
Functional block · DDII
Dual DC-feed isolation 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
Shows the isolation boundaries between two separately identified control-power feeds.
A simple example
In a switchgear lineup, separate protected branches may feed trip coils, closing coils and protection electronics. Their alarm contacts help the station controller identify which operating capability is unavailable. For this reference, the drawing identifies “Two DC supply paths” at the input and “Isolated control-power inputs” at the output. Redundancy requires assessment of common components.
What the drawings help you do
Start at the named input: Two DC supply paths. Identify its source device or document and the state represented on the drawing. Follow the named output: Isolated control-power inputs. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Two DC supply paths
- Output
- Isolated control-power inputs
- Application reference
- An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.
Read the source: SEL-RPM redundant power module
Schematic · DDII
What it represents
Shows the isolation boundaries between two separately identified control-power feeds. Control power supplies the command, protection and indication equipment associated with a switchgear assembly. The drawing must distinguish the source, each distribution branch and the functions lost if that branch fails.
In a switchgear lineup, separate protected branches may feed trip coils, closing coils and protection electronics. Their alarm contacts help the station controller identify which operating capability is unavailable. For this reference, the drawing identifies “Two DC supply paths” at the input and “Isolated control-power inputs” at the output. Redundancy requires assessment of common components.
Follow the actual positive, negative or neutral returns and the protective device on each branch. A healthy voltage indication does not establish that every downstream path can deliver its required operating current. 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: Two DC supply paths. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Isolated control-power inputs. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Redundancy requires assessment of common components.
- Follow the actual positive, negative or neutral returns and the protective device on each branch. A healthy voltage indication does not establish that every downstream path can deliver its required operating current.
Information to show or reference
- Label the source and connection reference for two dc supply paths.
- Identify the destination and defined state of isolated control-power inputs.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Redundancy requires assessment of common components.
A distinction that matters
Redundancy requires assessment of common components. 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.
SEL-RPM redundant power module
Public technical context for switchgear control-power supervision. Independent AC and DC sources for station auxiliary power. 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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