# Tap-changer motor-protection interface

Canonical URL: https://eloragrid.ai/symbols/tap-changer-motor-protection-interface
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: TMI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: substations
Input: Drive protective-device contact
Output: Tap-drive fault input

Reports the assigned tap-drive motor protective-device operation.

## In plain English

### What this block does

Reports the assigned tap-drive motor protective-device operation.

### A simple example

In a substation, a voltage regulator can request a tap change and check the resulting tap-position feedback. A separate controller stages cooling equipment according to the transformer manufacturer's defined conditions. For this reference, the drawing identifies “Drive protective-device contact” at the input and “Tap-drive fault input” at the output. A motor fault differs from a regulator fault.

### What the drawings help you do

Start at the named input: Drive protective-device contact. Identify its source device or document and the state represented on the drawing. Follow the named output: Tap-drive fault input. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Drive protective-device contact
- Output: Tap-drive fault input
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Drive protective-device contact → TMI → Tap-drive fault input
A reading guide. The entry's original illustration and input/output facts describe this application.

- [SEL-2414 transformer monitor](https://selinc.com/products/2414/)


## What it represents

Reports the assigned tap-drive motor protective-device operation. Transformer regulation changes the selected winding connection to influence voltage, while cooling control manages the installed fans and pumps. Commands, mechanical position and measured results belong to different parts of the diagram.
In a substation, a voltage regulator can request a tap change and check the resulting tap-position feedback. A separate controller stages cooling equipment according to the transformer manufacturer's defined conditions. For this reference, the drawing identifies “Drive protective-device contact” at the input and “Tap-drive fault input” at the output. A motor fault differs from a regulator fault.
Keep tap-change permission, limit contacts, movement indication and measured voltage distinct. Actual tap positions, time delays, cooling ratings and allowable parallel operation require the selected transformer control design. 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: Drive protective-device contact. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Tap-drive fault input. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- A motor fault differs from a regulator fault.
- Keep tap-change permission, limit contacts, movement indication and measured voltage distinct. Actual tap positions, time delays, cooling ratings and allowable parallel operation require the selected transformer control design.

## Information to show or reference

- Label the source and connection reference for drive protective-device contact.
- Identify the destination and defined state of tap-drive fault input.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: A motor fault differs from a regulator fault.

## Important distinction

A motor fault differs from a regulator fault. 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: Substations
- Input / boundary: Drive protective-device contact
- Output / connection: Tap-drive fault input
- Lookup label: TMI is a library lookup label, not a standard device designation.

## Public references

- [SEL-2414 transformer monitor](https://selinc.com/products/2414/) — SEL. Public technical context for transformer regulation and cooling control. Transformer temperature, cooling, tap changing and parallel operation. 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.