K
Minimum-voltage measuring relay
Measuring relay that operates when voltage falls below a set level while some voltage is still present.
Schematic / SLD
IEEE / ANSI · K
ANSI/IEEE Minimum-voltage measuring relay form
IEEE-library form of minimum-voltage measuring relay: measuring relay that operates when voltage falls below a set level while some voltage is still present.
In plain English
What does ANSI/IEEE Minimum-voltage measuring relay form mean?
This reference locates minimum-voltage measuring relay in Autodesk's IEEE-oriented voltage protection relays family. The minimum-voltage relay form operates when the measured voltage falls below its setting. It is used for motor undervoltage tripping, load shedding and transfer schemes, where a sustained voltage dip indicates a supply problem rather than a momentary disturbance. The public library uses HCR1F35 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
The symbol shows the voltage quantity and the less-than threshold but not the time delay, which phases are monitored or whether operation is blocked on VT fuse failure. Without a blocking input a blown VT fuse can cause an unwanted trip, so the supervision arrangement should be cross-referenced. Check which phase voltages are monitored. A minimum-voltage relay responds to a reduced voltage; a loss-of-voltage relay responds to absence of voltage. 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 minimum-voltage measuring relay: measuring relay that operates when voltage falls below a set level while some voltage is still present. A minimum-voltage relay responds to a reduced voltage; a loss-of-voltage relay responds to absence of voltage.
- 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.
- Phase
- One of the related AC waveforms in a power system.
Read the source: Autodesk IEEE Symbol Preview: Voltage Protection Relays · IEC graphical symbols for diagrams
IEEE / ANSI · Minimum Voltage Protection
Autodesk IEEE Symbol Preview: Voltage Protection Relays, block HCR1F35. 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.
Schematic / SLD · K
What it represents
This reference locates minimum-voltage measuring relay in Autodesk's IEEE-oriented voltage protection relays family. The minimum-voltage relay form operates when the measured voltage falls below its setting. It is used for motor undervoltage tripping, load shedding and transfer schemes, where a sustained voltage dip indicates a supply problem rather than a momentary disturbance. The public library uses HCR1F35 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.
The symbol shows the voltage quantity and the less-than threshold but not the time delay, which phases are monitored or whether operation is blocked on VT fuse failure. Without a blocking input a blown VT fuse can cause an unwanted trip, so the supervision arrangement should be cross-referenced. Check which phase voltages are monitored. A minimum-voltage relay responds to a reduced voltage; a loss-of-voltage relay responds to absence of voltage. 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
- Check which phase voltages are monitored.
- Look for VT supervision or fuse-failure blocking.
Information to show or reference
- State threshold and delay
- Show VT source
- Reference blocking input
A distinction that matters
A minimum-voltage relay responds to a reduced voltage; a loss-of-voltage relay responds to absence of voltage.
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 HCR1F35 as Minimum Voltage Protection. This supports the vendor convention context, not reproduction of the publisher graphic.
IEC graphical symbols for diagrams
IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced.
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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