The National Electrical Manufacturers Association (NEMA) published
TR 1-2013 Transformers, Regulators and Reactors.
This publication applies to single-phase and polyphase power and distribution transformers (including step-voltage regulators and reactors). Step-voltage regulators have been added to the scope in this edition and there is now more alignment with IEEE transformer standards. NEMA TR 1 is one of the few standards on the market that lists audible sound levels for these particular transformers.
TR 1-2013 may be downloaded at no cost or purchased in hardcopy for $55 on the NEMA website.
The National Electrical Manufacturers Association (NEMA) represents nearly 350 electrical, medical imaging, and radiation therapy manufacturers at the forefront of electrical safety, reliability, resilience, efficiency, and energy security. Our combined industries account for more than 400,000 American jobs and more than 7,000 facilities across the United States. Domestic production exceeds $117 billion per year.