# Motor stalled-start trip interface

Canonical URL: https://eloragrid.ai/symbols/motor-stalled-start-trip-interface
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MSTI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Starting current and timing
Output: Stalled-start trip request

Transfers detection of an unsuccessful acceleration condition to the feeder trip path.

## In plain English

### What this block does

Transfers detection of an unsuccessful acceleration condition to the feeder trip path.

### 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 “Starting current and timing” at the input and “Stalled-start trip request” at the output. Thresholds require the selected motor protection study.

### What the drawings help you do

Start at the named input: Starting current and timing. Identify its source device or document and the state represented on the drawing. Follow the named output: Stalled-start trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Starting current and timing
- Output: Stalled-start trip request
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Starting current and timing → MSTI → Stalled-start trip request
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

Transfers detection of an unsuccessful acceleration condition to the feeder trip path. 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 “Starting current and timing” at the input and “Stalled-start trip request” at the output. Thresholds require the selected motor protection study.
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: Starting current and timing. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Stalled-start trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Thresholds require the selected motor protection study.
- 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 starting current and timing.
- Identify the destination and defined state of stalled-start trip request.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Thresholds require the selected motor protection study.

## Important distinction

Thresholds require the selected motor protection study. 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: Starting current and timing
- Output / connection: Stalled-start trip request
- Lookup label: MSTI 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.