Energy efficiency

Great potential for CO2 reduction

The new edition of the EU Ecodesign Directives for electric motors brings with it a number of corrections that are likely to play a major role for both operators and machine manufacturers.

Update of Ecodesign Directive for three-phase motors

As of July 1, 2021, almost all three-phase motors in the range from 750 W to 1 MW must comply with motor efficiency class IE3 or higher.

Preliminary: There are about 8 billion electric motors in use in the EU, consuming almost 50% of the electricity generated in the EU. With a wide variety of technologies, applications and sizes, from small motors for operating cooling fans in computers all the way to very large motors for heavy industry, the sector is very heterogeneous. It is therefore no wonder that the EU Commissioners and bodies keep an eye on this.


For three-phase motors, the IE3 efficiency motors 2017 became mandatory almost across the board. Only the combination of IE2 motors with frequency converters and very small and very large power ratings as well as a few special designs have been excluded so far. These gaps will now be closed by the middle of 2021.

What does that mean for machine manufacturers in concrete terms?

In the range from 750 W to 1 MW, all three-phase asynchronous motors must in future comply with efficiency class IE3 or higher. This can lead to other designs and result in both electrical and mechanical adjustments.

It is therefore advisable to look at the complete drive train:

Does the power output of the motor match the application?

Often motors are oversized at the beginning and in practice are actually not needed in that size.

Is an electronic speed adjustment really needed or could the motor be operated more efficiently at rated speed?

Especially regarding series machines, thoughts in this direction can save a lot of money.

Even plant operators are affected

In case of modernization or in case of failure, they will now only be offered the modern efficiency motors as a replacement. But replacing the motor alone is not enough. This is because the significantly higher inrush current in efficiency motors can overburden previously used switching and protection devices and lead to false tripping during start-up. Consequently, protection and switching devices designed for this purpose must be used. Siemens has designed its complete portfolio of the Sirius product family accordingly and is thus IE3/4-ready. In order to avoid unpleasant surprises in the event of a malfunction, it is recommended that you deal with the situation in advance and keep suitable components at hand.

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