# Accelerating or decelerating device

Canonical URL: https://eloragrid.ai/protection-functions/18-accelerating-or-decelerating-device
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: 18
Drawing use: SLD, Schematic
Reference families: IEEE / ANSI

Controls a machine action that changes its operating speed during a sequence.

## What it represents

Controls a machine action that changes its operating speed during a sequence.
In a drafting package, connect this reference to the acceleration or deceleration command. The associated drawing should trace the drive, starter or governor interface; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.

## How to read it

- Identify the acceleration or deceleration command.
- Trace the drive, starter or governor interface.

## Information to show or reference

- Label the acceleration or deceleration command.
- Cross-reference the drive, starter or governor interface.
- Identify the device tag, manual revision and logic drawing that define this implementation.

## Important distinction

The speed-changing action differs from the speed limit supervision provided by devices 12 and 14.

## Facts

- ANSI / IEEE function number: 18
- Drawing context: The acceleration or deceleration command
- Application scope: Protection or apparatus-control role; exact implementation is defined by the equipment documentation.

## Public references

- [ANSI device-number and suffix reference table](https://selinc.com/pt/products/tables/ansi/) — Schweitzer Engineering Laboratories. Public manufacturer number/name association. Drafting explanations are independently written.
- [IEEE C37.2-2022: power-system device function numbers](https://ieeexplore.ieee.org/document/9984140) — IEEE. Normative device-number publication; exact edition wording and compliance require the licensed standard.

## 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.