Isolator
Disconnector
A switching device providing an electrical isolation function.
SLD / Schematic
Functional block · MDLSI
Motor-operated disconnector limit switch interface
Functional block · Switchyards
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
Carries the selected mechanism's end-position contacts into the yard control circuit.
A simple example
In a switchyard bay, a bus selector can use a different physical construction from a line disconnector. Each device still needs an identified operating mechanism, position indication and interlocking interface. For this reference, the drawing identifies “Drive end-position contacts” at the input and “Open and closed position inputs” at the output. Motor-stop limits and indication contacts may differ.
What the drawings help you do
Start at the named input: Drive end-position contacts. Identify its source device or document and the state represented on the drawing. Follow the named output: Open and closed position inputs. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Drive end-position contacts
- Output
- Open and closed position 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: Disconnectors and earthing switches
Schematic · MDLSI
What it represents
Carries the selected mechanism's end-position contacts into the yard control circuit. Disconnector and earthing references identify different mechanical constructions and connection duties within a yard. The primary diagram shows which conductors are joined or earthed; the equipment drawing explains how its contacts and supports move.
In a switchyard bay, a bus selector can use a different physical construction from a line disconnector. Each device still needs an identified operating mechanism, position indication and interlocking interface. For this reference, the drawing identifies “Drive end-position contacts” at the input and “Open and closed position inputs” at the output. Motor-stop limits and indication contacts may differ.
The construction name does not establish load-breaking capability, short-circuit making duty or operating permission. Verify these properties in the selected equipment data and the station interlocking scheme. 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: Drive end-position contacts. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Open and closed position inputs. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Motor-stop limits and indication contacts may differ.
- The construction name does not establish load-breaking capability, short-circuit making duty or operating permission. Verify these properties in the selected equipment data and the station interlocking scheme.
Information to show or reference
- Label the source and connection reference for drive end-position contacts.
- Identify the destination and defined state of open and closed position inputs.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Motor-stop limits and indication contacts may differ.
A distinction that matters
Motor-stop limits and indication contacts may differ. 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.
Disconnectors and earthing switches
Public technical context for disconnector and earthing applications. Disconnector construction, earthing switches and operating mechanisms. 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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