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AC induction motors have been around for well over 100 years. The technology at its core has remained unchanged as marginal improvements have been made. These improvements usually come in the form of motor efficiency and motor size.

The chart below shows the motor efficiency improvements through the years. For each horsepower class the ratings have steadily increased in efficiency.

history of motor efficiency improvements
Premium Efficiency Motor Selection and Application Guide Table 3-3. History of Motor Efficiency Improvements, Energy.gov

With these innovations worldwide organizations began to form new standards. Both NEMA and IEC have determined the below standards to describe these efficiency ratings.

NEMA IEC Motor Efficiency Rating
Premium Efficiency Motor Selection and Application Guide Table 2-2. Comparable Levels of Energy Efficiency, Energy.gov


Motor Efficiencies
Premium Efficiency Motor Selection and Application Guide Appendix B: Motor Minimum Full-Load Efficiency Standards, Energy.gov

Starting January 1st, 2017, every motor manufacturer in the USA has been required by the Department of Energy (DOE) to maintain a “Premium Efficiency” or “IE3” minimum rating for their motors. This long and involved process of approval requires manufacturers to test motors under strict conditions while adhering to minimum efficiency standards.

Many smaller manufacturers are not able to complete testing to become IE3 approved. This is something to keep in mind especially when selecting blower technologies such as the Regenerative Blower. When operating in the USA one would be required to use a Premium Efficiency or IE3 motor.

The Republic Manufacturing CC number for our Regenerative Blowers is CC339B which approves our motor efficiency compliance. These CC numbers are publicly available and can be provided upon request. If a manufacturer cannot provide a CC number, they are likely not in compliance with the Department of Energy.

Click here to view Republic Manufacturing’s complete IE3 certified regenerative blower line.


[1]        U.S. Department of Energy, Energy Efficiency and Renewable Energy, Premium Efficiency Motor Selection And Application Guide: A Guidebook for Industry, https://www.energy.gov/sites/prod/files/2014/04/f15/amo_motors_handbook_web.pdf

[2]        Premium efficiency, Premium efficiency electrical motors, Unifying worldwide efficiency classifications, https://en.wikipedia.org/wiki/Premium_efficiency