U LOSS
Loss-of-voltage monitoring relay
A loss-of-voltage relay changes its output for a documented absence-of-voltage condition.
SLD / Schematic
IEEE / ANSI · U LOSS
ANSI/IEEE Loss-of-voltage monitoring relay form
IEEE-library form of loss-of-voltage monitoring relay: a loss-of-voltage relay changes its output for a documented absence-of-voltage condition.
In plain English
What does ANSI/IEEE Loss-of-voltage monitoring relay form mean?
This reference locates loss-of-voltage monitoring relay in Autodesk's IEEE-oriented voltage protection relays family. A loss-of-voltage relay changes its output for a documented absence-of-voltage condition. Schematics distinguish measurement failure, actual source loss and auxiliary-supply loss where the design requires them. The public library uses HCR1F39 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.
A simple example
Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation.
What the drawings help you do
Trace the monitored voltage independently from relay auxiliary power. Loss-of-voltage indication is not necessarily the same function as breaker undervoltage release. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted.
This particular reference
IEEE-library form of loss-of-voltage monitoring relay: a loss-of-voltage relay changes its output for a documented absence-of-voltage condition. Loss-of-voltage indication is not necessarily the same function as breaker undervoltage release.
- Normally open / normally closed
- The contact state in the normal condition defined for the drawing.
- Coil
- A wound conductor that can produce a magnetic field when energised.
- Terminal
- An identified point where a conductor connects.
Read the source: Autodesk IEEE Symbol Preview: Voltage Protection Relays
IEEE / ANSI · Lack of Voltage Protection
Autodesk IEEE Symbol Preview: Voltage Protection Relays, block HCR1F39. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
SLD / Schematic · U LOSS
What it represents
This reference locates loss-of-voltage monitoring relay in Autodesk's IEEE-oriented voltage protection relays family. A loss-of-voltage relay changes its output for a documented absence-of-voltage condition. Schematics distinguish measurement failure, actual source loss and auxiliary-supply loss where the design requires them. The public library uses HCR1F39 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.
Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation.
Trace the monitored voltage independently from relay auxiliary power. Loss-of-voltage indication is not necessarily the same function as breaker undervoltage release. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted.
How to read it
- Trace the monitored voltage independently from relay auxiliary power.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.
Information to show or reference
- Identify monitored source
- State loss criterion
- Show output and supply-loss behaviour
A distinction that matters
Loss-of-voltage indication is not necessarily the same function as breaker undervoltage release.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Autodesk IEEE Symbol Preview: Voltage Protection Relays
Public IEEE-oriented Voltage Protection Relays table explicitly lists HCR1F39 as Lack of Voltage Protection. This supports the vendor convention context, not reproduction of the publisher graphic.
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. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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