# Reversing-starter electrical interlock

Canonical URL: https://eloragrid.ai/symbols/reversing-starter-electrical-interlock
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: REI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Forward and reverse status
Output: Opposite-coil inhibit

Blocks energization of opposite-direction contactors according to their documented feedback.

## In plain English

### What this block does

Blocks energization of opposite-direction contactors according to their documented feedback.

### A simple example

In a switchroom motor-control panel, a ventilation motor can receive an automatic start request while a local selector and the motor protection determine whether the feeder is available. For this reference, the drawing identifies “Forward and reverse status” at the input and “Opposite-coil inhibit” at the output. Mechanical interlocking may also be required.

### What the drawings help you do

Start at the named input: Forward and reverse status. Identify its source device or document and the state represented on the drawing. Follow the named output: Opposite-coil inhibit. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Forward and reverse status
- Output: Opposite-coil inhibit
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Forward and reverse status → REI → Opposite-coil inhibit
A reading guide. The entry's original illustration and input/output facts describe this application.

- [SEL-710 motor protection and control](https://selinc.com/products/710/)


## What it represents

Blocks energization of opposite-direction contactors according to their documented feedback. A motor feeder combines switching, motor protection and an operating command. Starting permission, running feedback and protection trip are different signals even where one relay or controller processes all of them.
In a switchroom motor-control panel, a ventilation motor can receive an automatic start request while a local selector and the motor protection determine whether the feeder is available. For this reference, the drawing identifies “Forward and reverse status” at the input and “Opposite-coil inhibit” at the output. Mechanical interlocking may also be required.
Link the motor tag to its contactor, protective device and process permissives. The control diagram must identify stop priority, feedback and restart philosophy without supplying unverified settings. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation.

## How to read it

- Start at the named input: Forward and reverse status. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Opposite-coil inhibit. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Mechanical interlocking may also be required.
- Link the motor tag to its contactor, protective device and process permissives. The control diagram must identify stop priority, feedback and restart philosophy without supplying unverified settings.

## Information to show or reference

- Label the source and connection reference for forward and reverse status.
- Identify the destination and defined state of opposite-coil inhibit.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Mechanical interlocking may also be required.

## Important distinction

Mechanical interlocking may also be required. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

## Facts

- Representation: Functional block
- Installation focus: Switchgear
- Input / boundary: Forward and reverse status
- Output / connection: Opposite-coil inhibit
- Lookup label: REI is a library lookup label, not a standard device designation.

## Public references

- [SEL-710 motor protection and control](https://selinc.com/products/710/) — SEL. Public technical context for motor-feeder control interfaces. Motor feeder thermal, starting and control functions. The application text and educational graphic are independently authored; the publisher does not certify this representation.

## 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.