Skip to main content

Tip of the Week Archive

Infrared Inspections of Dry-type Transformers

May 30, 2022

Sponsored by:

II_logo
Infrared Inspections of Dry-type Transformers
Tip written by: Infraspection Institute

A thorough infrared inspection of an electrical transformer can point out symptoms of loose connections as well as other possible problems. When performing an infrared inspection of a dry-type transformer, be certain to include not only the primary and secondary connections but also the following items as well:

1) Inspect neutral and grounding connections for hot spots.

2) Compare phase coils to each other. Transformers with balanced loads will exhibit similar temperatures between windings.

3) Compare each phase coil to itself. Properly operating coils should exhibit no pronounced hot or cold spots.

4) Inspect voltage tap jumper connections. Both connections should be the same temperature. In most cases, the jumper will be colder than the windings.

Thermogram reveals hot spot caused by loose tap connection
Thermogram reveals hot spot caused by loose
tap connection

5) Compare transformer operating temperature to nameplate rating. For long term service, transformers should not operate above their maximum rated temperature.

In conjunction with the infrared inspection, cooling fans should be checked for proper settings and operation.

Finally, transformers require proper air circulation for cooling. To help ensure maximum airflow, transformer ventilation openings should be unobstructed and free from dirt.

Infrared inspection of power distribution systems is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.

Visit Infraspection Institute Web Site

Advertisement

Latest Tips

Temperature Differentials for Infrared Building Inspections – Part 1

December 02, 2024

Thanksgiving Safety Tip

November 25, 2024

Gauging When IR Inspection Window Opens/Closes

November 18, 2024

Is Distance Learning Right For You?

November 11, 2024

Standards for Infrared Thermography

November 04, 2024