49
Thermal protection
A thermal protection function for a documented machine or transformer application.
Protection functions
Protection functions · 26
Apparatus thermal device
Responds to the temperature of equipment or a monitored part of that equipment.
SLD / Schematic · 26
What it represents
Responds to the temperature of equipment or a monitored part of that equipment.
In a drafting package, connect this reference to the thermal sensor location and contact type. The associated drawing should trace the alarm, trip or cooling-control destination; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.
How to read it
- Identify the thermal sensor location and contact type.
- Trace the alarm, trip or cooling-control destination.
Information to show or reference
- Label the thermal sensor location and contact type.
- Cross-reference the alarm, trip or cooling-control destination.
- Identify the device tag, manual revision and logic drawing that define this implementation.
A distinction that matters
An apparatus thermal device can be a direct sensor or switch; a 49 function may instead use a calculated thermal model.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
ANSI device-number and suffix reference table
Public manufacturer number/name association. Drafting explanations are independently written.
IEEE C37.2-2022: power-system device function numbers
Normative device-number publication; exact edition wording and compliance require the 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.