Efficiency Classes of Motors and
Measuring Methods The “efficiency” describes
how efficiently an electric motor
transforms electrical energy into mechanical
energy. Previously in Europe, low voltage
three-‐phase motors have been graded
and marketed in three efficiency classes
– EFF3, EFF2 and EFF1 – based
on a voluntary agreement between motor
manufacturers and the European Commission.
This classifica-on system is well
proven and has now been adapted in
many countries around the world.
Unfortunately, other countries have also
developed their own na-onal systems, which
are very different from the
European system. That was the reason
for the German motor manufacturers in
ZVEI, with the support of their
European neighbours, to develop an energy
efficiency standard for the Interna-onal
Electrotechnical Commission (IEC). The
objec-ve was to have a common
interna-onal standard that replaces all the
different na-onal systems. This project
was successful and the objec-ve has
been met. The new interna-onal
standard, IEC 60034-‐30:2008, defines efficiency
classes IE1, IE2 and IE3 for
three-‐ phase motors. This ensures a
common interna-onal basis for the design
and classifica-on of motors as well
as for na-onal legisla-ve ac-vi-es.
At the same -me, the IEC developed
improved methods for determining the
efficiency of these motors. The
interna-onal standards IEC 60034-‐30:2008
(classifica-on) and IEC 60034-‐2-‐1:2007 (measuring
methods) have been adopted as
European standards without any changes as
EN 60034-‐30:2009 and EN 60034-‐2-‐1:2007.
For the sake of simplicity, the
following sec-ons will refer to the
IEC standards only.
