Electric motors

Increasing the efficiency of electric motors - one of the biggest energy efficiency opportunities

How International Standards for electric motor systems support policies of countries using these in their regulations

provided by Conrad U. Brunner, Rita Werle, Zurich, Switzerland and Maarten van Werkhoven, Amsterdam, the Netherlands

According to the IEA1 electric motor driven systems are responsible for 53% of global electricity use. The IEC has contributed to the definition of energy-efficient electric motor systems through the internationally relevant test standard IEC 60034-2-1 for electric motors and the IEC 60034-30-1 classification scheme comprising four levels of motor efficiency ("IE-code"):

  • IE1 Standard Efficiency
  • IE3 Premium Efficiency
  • IE2 High Efficiency
  • IE4 Super Premium Efficiency

These IE-codes serve as a reference for governments who specify the efficiency levels for their minimum energy performance standards (MEPS).


European Union

The European Union has first set motor MEPS in 2009 and has after 10 years upgraded its minimum requirements in 2019 with regulation number 2019/1781 covering a larger scope: electric motors from 0.12 kW to 1000 kW output power including 2-, 4-, 6- and 8-pole motors. From 1 July 2021 motors between 0.75 kW and 1000 kW will be required to meet a minimum efficiency class of IE3, the group of smaller motors from 0.12 kW to 0.75 kW minimum IE2. From 1 July 2023, motors between 75 kW and 200 kW will be required to meet the even higher efficiency class of IE4.

All the details are available here.


The European Union has also included for the first time requirements for converters in the 2019/1781 motor regulation based on IEC 61800-9-2, edition 1. From 1 July 2021, the minimum requirement is IE2 class of losses of converters between 0.12 kW and 1000 kW. 

1) IEA, International Energy Agency: World Energy Outlook 2016, Paris, France, 2016


The USA was the first country in the world to set MEPS for motors. In 1997 (Energy Policy Act) the minimum required level was set at the equivalent of IE2. In 2007 (Energy Independence and Security Act) the MEPS were raised to the equivalent of the IE3 level (NEMA Premium), in 2015 the scope was further widened to include small polyphase motors from 0.18 kW up to 2.2 kW with IE3 and single-phase with IE2. The USA currently recognizes in its legal requirements the national testing standard IEEE 112B, the Canadian test standard CSA390 but not yet the IEC test Standard IEC 60034-2-1 (the differences are minimal). The adjustment of the requirements to allow testing according to the IEC standard is under consideration.


Flag_of_Australia.jpg Flag-New-Zealand.jpg

Australia and New Zealand set MEPS levels for 0.75 kW to 185 kW at IE2 in 2000 (AS/NZS 1359.5-2000), effective since 2001, based since 2018 on the IEC test standard IEC 60034-2-1. 



China has upgraded in 2019 its motor efficiency standard GB 18613 for small and medium three-phase asynchronous motors for 0.12 - 1000 kW and 2-, 4-, 6- and 8-poles aligned with IEC standards. It still has kept its motor MEPS from 0.75 kW to 375 kW at the IE2 level with the date of the formal enforcement of the more advanced MEPS with IE3 and IE4 as a reach standard pending. 



Japan decided to align its national JIS  with IEC efficiency classes and to include electric motors at the IE2 and IE3 level in its Toprunner programme in 2014.


India has a comparative efficiency label since 2009 and a voluntary standard on IE2 level since 2012.

In 2020, the point was reached where countries consuming 76% of the global electricity consumption by electric motor systems have set MEPS for motors at either IE2 or IE3 level. This is a high level of international alignment for a globally traded product, recognizing at the same time that MEPS can differ according to the market situation of individual countries or regions. The barriers to trade are reduced through the transparent nomenclature and definitions of the IE-code (MEPS levels at IE2 / IE3 / IE4). 

Motor energy efficiency standards used around the world



Nationally Required Minimum Energy Performance Standards; IEC Efficiency Classes and Testing Standards (source: EMSA 2020)


The focus on motor efficiency has shifted from the product "motor" to the "Electric Motor Driven System" which is the system consisting of the motor control with a variable frequency converter, the motor itself, the mechanical equipment and the driven application (pump, fan, compressor, etc.).

Electric Motor Driven Systems (EMDS)

It is widely accepted that the efficiency improvement and the subsequent energy savings in EMDS can only be achieved with an integrated system consisting of well-matched and highly efficient individual components that is operated according to the required load in an efficient way.



Electric Motor Driven System (EMDS)


IEC 61800-9-2, edition 1, 2017 was published as a test standard and an efficiency classification for converters. The Group Efficiency Standard IEC 61800-9-1 defines the interface between the electrical and the mechanical part of the EMDS. In IEC 60034-2-3, 2020 a test method was published for motors driven by converters.
Also, in IEC TS 60034-30-2, 2016 an efficiency classification for motors driven by converters was published.



Pump system, (source: EcoAmbassador Academy)


In 2019, IEC ACEE2 formed a Task Group 6 to explore the possibilities of coordinating and aligning international IEC and ISO standards for energy-efficient EMDS (CAISEMS). A CAISEMS project group met in September 2019 in Tokyo Japan to plan the interaction of 3 IEC and 6 ISO TC's dealing with EMDS. The eventual goal is to define a Basic (or a Group) standard, according to the rules stated in IEC Guides 118 and 119, for the benefit of better-aligned systems that can be more energy-efficient and more cost-effective.



IEC and ISO Technical Committees involved in Electric Motor Driven Systems

 2 IEC ACEE: Advisory Group for Energy Efficiency


In conclusion, it can be seen in the case of electric motors and electric motor-driven systems that international standards offer a valid and widely accepted reference for countries to define appropriate Minimum Energy Performance Standards in their jurisdictions. Namely, by:

  1. Defining a testing method for determining the product efficiency (e.g. for the electric motor, converter)
  2. Defining an efficiency classification scheme to be able to categorize the product efficiency levels (e.g. for the electric motor, converter)
  3. Taking into account individual elements of the system (like the electric motor or the converter) but also the interplay of these individual elements on the system level (which is the goal of the CAISEMS project).

These international standards provide a robust basis for regulations and are a result of a negotiation process in the standards development bodies, representing a wide range of countries. This is also an effective way of pooling resources, allowing countries to put much less effort in their own national standards development, in case international standards are considered suitable for their regulatory purposes.


Pierre Angers, Andrew Baghurst, Martin Doppelbauer: Motor energy efficiency measurement standards used around the world. Review of Energy Efficiency Measurement Standards for Induction Motors in the Context of the IECEE Global Efficiency Labeling Initiative, EEMODS'133, Rio de Janeiro, Brazil, 2013

Paul Waide, Conrad U. Brunner, et al.: Energy-Efficiency Policy Opportunities for Electric Motor-Driven Systems, IEA Energy Papers, Paris, France 2011

Maarten van Werkhoven, Rita Werle, Conrad U. Brunner, IEA 4E EMSA: Policy Guidelines for Motor Driven Units, 

•    Part 1: Analysis of standards and regulations for pumps, fans and compressors, Zurich, Switzerland 2016
•    Part 2: Recommendations for aligning standards and regulations for pumps, fans and compressors, Zurich, Switzerland 2018

3 EEMODS: International conference on Energy Efficiency in Motor Driven Systems, organized by the Joint Research Centre of the European Commission

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