IEC Standards for electric motors​

In short: the International Electrotechnical Commission (IEC) standards are the uniform standards indicating the efficiency classes for electric motors. In 1999, the European Commission established different efficiency classes for electric motors. They did this to reduce energy consumption and to create awareness of the importance of a more sustainable environment among various industries. These efficiency classes were called the EFF standards. However, the US established the NEMA standards for electric motors, which differed a lot from the EU standards. To overcome the international inconsistencies in regulations, the EFF standards changed to the current IEC standards for electric motors.

IEC efficiency classes

Since 2014, the power range was extended for electric motors and was set between 0,12 kW and 1000 kW. Moreover, electric motors with a rated output of 0,75-375 kW must meet either IE3 efficiency or IE2 if fitted with VSD’s since 2017. The IEC standards were established in 2008, they are classified as E1, IE2, IE3, IE4 and IE5.

Motors that fall witin the EI1 efficiency class have the following specifications:

    • Output is 0.75kW to 355kW.
    • Poles are 2, 4, 6, 8, 10 and 12.
    • Speed range is from 500rpm to 3600rpm. 
    • RPM frequency is 50Hz or 60Hz.
    • Temperature class is B class.
    • Insulation class is class F.
    • Protection technology used is IP55, IP56, IP65, IP66.

Motors that fall witin the EI2 efficiency class have the following specifications:

    • Output is 0.75kW to 355kW.
    • Poles are 2, 4 and 6.
    • Speed range is from 1000 rpm to 3600 rpm. 
    • RPM frequency is 50Hz or 60Hz.
    • Temperature class is B class.
    • Insulation class is class F.
    • Protection technology used is IP55, IP56, IP65, IP66.

Motors that fall witin the EI2 efficiency class have the following specifications:

    • Output is 0.75kW to 355kW.
    • Poles are 2, 4 and 6 and 8.
    • Speed range is from 750 rpm to 3600 rpm. 
    • RPM frequency is 50Hz or 60Hz.
    • Temperature class is B class.
    • Insulation class is class F.
    • Protection technology used is IP55, IP56, IP65, IP66.

Motors that fall witin the EI4 efficiency class have the following specifications:

    • Output is 2,2kW to 230kW.
    • Poles are 2, 4, 6 and 8.
    • Speed range is from 750 rpm to 3600 rpm. 
    • RPM frequency is 50Hz or 60Hz.
    • Temperature class is B class.
    • Insulation class is class F.
    • Protection technology used is IP55, IP56 and IP65.

The parameters of the IE5 efficiency class are still under develeopment by the IEC. They expect that motors within the IE5 Efficiency class will reduce energy losses by approximately 20% compared to the IE4 (super premium efficiency). For the new IE5 class it is important to focus on improving system efficiency throughout the entire operating load cycle including all system-losses (converter, filter, cables, motor etc.). IEC expects that this will have a big role in further energy-efficiency optimizations.

International electric motor efficiency standards​

IEC created a standard for indicating the efficiency classes of electric motors. Some countries use other efficiency standards. In many cases, the IEC efficiency levels overlap with these standards. Efficiency standards allow manufacturers and purchasers of electric motors to quantify efficiency, whether defined by IEC, NEMA or any other agency. The following table shows a comparison between the IEC standards (IEC/EN 60034-20-01) and other international norms.

IEC efficiency standards comparison with nema eev and eisa

Electric motors included by the IEC standards

    • Single speed electric motors (single and three phase), 50 and 60 Hz
    • Line-start permanentmagnet motors
    • 2, 4, 6 or 8 poles
    • Rated output PN from 0.12 kW to 1000 kW
    • Rated voltage UN above 50 V up to 1 kV
    • Motors, capable of continuous operation at their rated power with a temperature rise within the specified insulation temperature class

Electric motors excluded by the IEC standards

    • Motors designed to operate wholly immersed in a liquid
    • Brake motors, when the brake cannot be dismantled or separately fed.
    • Single-speed motors with 10 or more poles or multi-speed motors
    • Motors completely integrated into a machine (for example, pump, fan or compressor) that cannot be tested separately from the machine.
    • Motors specifically designed to operate:
      • At altitudes exceeding 4000 meters (over 13.000 feet)
      • Where ambient air temperatures exceed 60°C
      • In maximum operating temperatures above 400°C.
      • Where ambient air temperatures are less than –30°C (any motor) or less than 0°C (water-cooled motors)
      • Where the water coolant temperature at the inlet to a product is less than 0°C or exceeds 32°C
      • In potentially explosive atmospheres as defined in Directive 94/9/EC

IEC specifications​

The realized efficiency of an electric motor depends not only on the design, but also on the motor size. The table and graph below show the efficiency at 50HZ. The difference in efficiency is the biggest for smaller engines. The difference becomes smaller with large engines, which is clearly shown in the graph below.

Tabel IEC Rendement bij 50Hz (2,4,6 and 8 poles)

Motors by Magnetic Innovations that meet Super premium efficiency

Over the next years, the world will face challenges to reduce carbon emission levels. Saving energy and using energy more efficiently are key to addressing the challenges. Magnetic Innovations motors are very energy efficient. Implementing our motors in your applications can result in enormous energy savings. Our torque motors and belt drive motors, which we designed and manufactured, fall within the IE4 super premium efficiency class. Our EC Fan motor, meets IE5 efficiency class.

Contact us for more information