Efficiency Classes of Motors:
The “efficiency” describes how efficiently an electric motor transforms electrical energy into mechanical energy. Previously in Europe, low voltage three-phase motors defined for the power range of 1.1 kW to 90 kW have been graded and marketed in three efficiency classes – EFF3, EFF2 and EFF1.
Now the new international standard, IEC 60034-30:2008, defines efficiency classes IE1, IE2 and for low voltage three-phase motors with a power range from 0.75 kW to 375 kW. “IE“ stands for “International Efficiency“ and is combined with a number. This ensures a common international basis for the design and classification of motors.