New Efficiency Classes 

for Low-Voltage 3-phase Motors

Along with the international discussion on energy efficiency, a worldwide harmonized energy efficiency classification system has been established for low voltage three-phase asynchronous motors.


The efficiency factor defines the efficiency of motors when transforming electrical into mechanical energy.
For many years low-voltage three-phase motors have been sold in the European Union in three efficiency classes EFF3, EFF2 and EFF1.

Aside from this, many different efficiency classification systems have been introduced and well-proven in many countries all over the world. They differ from each other in terms of scope, wording and values.


That was the reason for the International Electrotechnical Commission IEC to develop and publish an energy efficiency standard which replaces all the previous national issues. Parallelly IEC developed and issued a new standard for determining motor efficiency.


The new IEC 60034-30 standard defines and harmonizes the worldwide efficiency classes IE1, IE2 and IE3 for low-voltage three-phase motors.

According to IEC 60034-30 standard and EU regulation 640/2009, 4/2014 starting from 1st January 2017, only IE3 Energy Efficiency motors from 0,75 kW to 375 kW can be sold.

The above mentioned efficiency classes were defined for general purpose motors with synchronous speed of 3000rpm or 1500rpm and with rated power from 1,1kW to 90kW (400V – 50Hz).


The agreed minimum levels of the respective classes are based on efficiency measurements according to the old IEC 60034-2 standard.

New international efficiency classes of motors (IE = International Efficiency)

The new IEC 60034-30 standard defines the following efficiency classes of low-voltage three-phase asynchronous motors in the power range from 0,75kW to 375kW worldwide:

IE1 = Standard Efficiency (comparable to EFF1)

IE2 = High Efficiency (comparable to EFF2)

IE3 = Premium Efficiency


From now on motors can be offered and sold within the new IE1, IE2 and IE3 classes. In that case, efficiency has to be determined according to the new measuring standard (IEC 60034-2-1).