# ANSI/IEEE tachometer symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-tachometer
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: TACH
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Instrumentation and Sensors form: Tachometer
Autodesk publishes this block under its IEEE Symbol Preview. The counterpart is the matching functional concept in the library; no equivalence of every detailed standard graphic is asserted.
Related representation: [Tachometer](https://eloragrid.ai/symbols/tachometer)

IEEE-library tachometer instrument form showing where machine speed is indicated from a speed transducer.

## In plain English

### What does ANSI/IEEE tachometer mean?

The tachometer form shows an indicating instrument whose quantity is rotational speed. In motor and generator control schematics it is normally fed from a tacho-generator, pulse pickup or drive analogue output, so the source device is drawn separately and wired to the instrument circle.

### A simple example

The circle does not say whether speed is displayed in rpm, percent of rated speed or frequency, and it carries no overspeed protection function. Overspeed or underspeed trips use separate devices or contacts and should not be inferred from the presence of a tachometer.

### What the drawings help you do

Identify the speed source feeding the meter. Check scaling between device that turns a measured quantity into a signal output and displayed speed. A tachometer indicates speed; a tachometric dynamo or pulse pickup is the device that turns a measured quantity into a signal that produces the speed signal.

### This particular reference

IEEE-library tachometer instrument form showing where machine speed is indicated from a speed device that turns a measured quantity into a signal. A tachometer indicates speed; a tachometric dynamo or pulse pickup is the device that turns a measured quantity into a signal that produces the speed signal.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Terminal: An identified point where a conductor connects.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.

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.

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm)
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/)


## What it represents

The tachometer form shows an indicating instrument whose quantity is rotational speed. In motor and generator control schematics it is normally fed from a tacho-generator, pulse pickup or drive analogue output, so the source device is drawn separately and wired to the instrument circle.
The circle does not say whether speed is displayed in rpm, percent of rated speed or frequency, and it carries no overspeed protection function. Overspeed or underspeed trips use separate devices or contacts and should not be inferred from the presence of a tachometer.

## How to read it

- Identify the speed source feeding the meter.
- Check scaling between transducer output and displayed speed.

## Information to show or reference

- Reference the speed transducer
- State displayed units
- Show any separate overspeed contact

## Important distinction

A tachometer indicates speed; a tachometric dynamo or pulse pickup is the transducer that produces the speed signal.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview, Instrumentation and Sensors
- Public vendor block name: HIN1TAC / VIN1TAC (Autodesk identifier; not an IEEE symbol number)
- Measured quantity: Rotational speed
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm) — Autodesk. Public IEEE-oriented Instrumentation and Sensors preview listing the Tachometer block and its vendor identifier.
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context and official status; not a source of reproduced artwork.

## 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.