49
Thermal protection
A thermal protection function for a documented machine or transformer application.
Protection functions
Protection functions · 49R
RTD-based thermal protection
Uses resistance-temperature-detector measurements for an equipment thermal protection function.
SLD / Schematic · 49R
What it represents
Uses resistance-temperature-detector measurements for an equipment thermal protection function.
The drafting record should connect this function to the RTD channel assignments, sensor wiring and monitored locations, then trace the thermal alarm and equipment trip outputs. Keep the complete designation and equipment tag together so that the SLD, relay logic and terminal schedule describe the same implementation.
The cited mapping is a public manufacturer example (SEL generator protection feature table). Suffixes are not universal equivalences across products, and this reference supplies neither a protection setting nor certification of the selected scheme.
How to read it
- Identify the RTD channel assignments, sensor wiring and monitored locations.
- Trace the thermal alarm and equipment trip outputs.
Information to show or reference
- Label the RTD channel assignments, sensor wiring and monitored locations.
- Cross-reference the thermal alarm and equipment trip outputs.
- Retain the complete suffix, selected device tag and manufacturer manual revision.
A distinction that matters
RTD-based 49R uses measured temperature; a current-driven thermal model can have a separate response and wiring arrangement.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Generator protection feature and function comparison
Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original.
IEEE C37.2-2022: power-system device function numbers
Device-number and suffix convention. This page is not a reproduction of the full licensed standard.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
Explore related references
Put the reference into a drawing workflow.
Elora Grid helps electrical teams work with drawings, specifications and equipment information. Explore the drafting workflow or join the early-access waitlist.