# Definite-time delay qualifier for measuring relays

Canonical URL: https://eloragrid.ai/symbols/definite-time-delay-measuring-qualifier
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: t
Drawing use: Schematic, SLD
Reference families: IEC

Qualifier added to a measuring relay symbol to show that operation follows a fixed time delay after pick-up.

## In plain English

### What does Definite-time delay qualifier for measuring relays mean?

This additional drawing mark is added inside or beside a measuring relay box to show that the relay operates a fixed time after its measured quantity crosses the threshold. Combined with a quantity such as I> or U<, it tells the reader the element is definite-time rather than instantaneous or inverse-time.

### A simple example

The additional drawing mark states the type of delay, not its value. The delay setting itself must appear in the settings table, and an element shown without any time additional drawing mark should not automatically be assumed to be instantaneous unless the legend says so.

### What the drawings help you do

Read the additional drawing mark together with the quantity and threshold sign. Take the actual delay value from the settings record. A definite-time additional drawing mark gives a fixed delay; an inverse-time additional drawing mark gives a delay that shortens as the quantity increases.

### This particular reference

additional drawing mark added to a measuring relay symbol to show that operation follows a fixed time delay after pick-up. A definite-time additional drawing mark gives a fixed delay; an inverse-time additional drawing mark gives a delay that shortens as the quantity increases.

### Terms

- Coil: A wound conductor that can produce a magnetic field when energised.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm)


## What it represents

This qualifier is added inside or beside a measuring relay box to show that the relay operates a fixed time after its measured quantity crosses the threshold. Combined with a quantity such as I> or U<, it tells the reader the element is definite-time rather than instantaneous or inverse-time.
The qualifier states the type of delay, not its value. The delay setting itself must appear in the settings table, and an element shown without any time qualifier should not automatically be assumed to be instantaneous unless the legend says so.

## How to read it

- Read the qualifier together with the quantity and threshold sign.
- Take the actual delay value from the settings record.

## Information to show or reference

- Pair with quantity and threshold
- State delay setting
- Confirm legend convention

## Important distinction

A definite-time qualifier gives a fixed delay; an inverse-time qualifier gives a delay that shortens as the quantity increases.

## Facts

- Meaning: Fixed delay after pick-up
- Applies to: Measuring relay symbols
- Preview: Independent educational concept; consult the applicable standard and project legend for the exact graphic

## Public references

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced.
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm) — Autodesk. Public IEC-context qualifier family showing how qualifiers modify a base symbol.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.