Audible sound levels in liquid-filled transformers

All transformers have a slight hum, or buzz when operating, but certain regulations are in place to ensure they are built to operate as quietly as practically possible.

March 12, 2020

How To's

All transformers have a slight hum (or buzz) when operating, but certain regulations are in place to ensure they are built to operate as quietly as practically possible.

Below are the latest NEMA TR-1 Average decibel ratings as of 2020.

Self-Cooled, Two Winding kVA Rating	Average Decibels (dB)
45-500	56
501-700	57
701-1000	58
1001-1500	60
1501-2000	61
2001-2500	62
2501-3000	63
3001-4000	64
4001-5000	65
5001-6000	66
6001-7500	67
7501-10000	68

Maddox Industrial Transformer liquid-filled padmount and substation transformers are built to the latest NEMA, IEEE, ANSI standards, and Department of Energy regulations.

Call us if you have any questions: 1-800-270-2011

Get more info

Find out how Maddox can power on your next project

Thank you!
Your submission has been received!

Oops! Something went wrong while submitting the form.

Green liquid filled padmounted transformer roped off for testing

November 15, 2022

Overview of the common tests performed on transformers, including Winding Resistance, Megger, Transformer Turns Ratio, Load-Loss, Leak Tests, and others.

How To's

August 9, 2022

Harmonics can be harmful for a transformer's operation. However, they can be mitigated by K-Factor rated transformers, Zigzag transformers, and other options.

How To's

Audible sound levels in liquid-filled transformers

Get more info

Suggested Articles:

Guide to transformer testing standards

Guide to transformer harmonics and k-factor