SIEMENS
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Siemens D 11 · 2015
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Overview
(continued)
2
Highlights
Energy efficiency classes in accordance with EN 50598
Advantages of the detailed loss consideration of EN 50598
over the previous consideration of efficiencies and maxi-
mum loss values
For motors, the efficiency consideration was previously only de-
fined for operation without a converter at 50/60 Hz. It provides a
good way of comparing the energy efficiency of motors from dif-
ferent manufacturers for this use case.
The more detailed loss analysis of EN 50598, on the other hand,
is aimed at speed-controlled operation and therefore now also
includes motors especially designed for converter operation in
the energy analysis. These were previously not covered by the
applicable standards.
Moreover, a loss analysis over the entire setting and load range
of the motor is possible. This is done in accordance with the
standard EN 50598 with typical values.
For holistic consideration, it is essential to include all the relevant
components of a drive system. The EN 50598 standard defines
this in detail. The standardized expression of power loss data as
a percentage makes comparison considerably easier and more
transparent.
The method also makes it possible to consider a motor that pro-
duces a holding torque at speed zero, for example. In this case,
the efficiency is zero, but a power loss from current producing
magnetization and holding torque does occur. In summary, the
key advantage of standard EN 50598 is the ability to perform the
energy analysis of an electrical drive system based on standard-
ized load profiles in all operating ranges due to uniform general
conditions. This provides the user with complete transparency
irrespective of the manufacturer.
Establishing efficiency classes of frequency converters
(Complete Drive Modules CDM)
To avoid overmodulation and to ensure comparability between
makes, which cannot be achieved otherwise, the efficiency
classes of CDMs refer to the 90/100 operating point (90 % motor
stator frequency, 100 % torque current).
Standard EN 50598-2 defines the relative losses of a CDM in ef-
ficiency classes IE0 to IE2. With reference to the value of a CDM
of efficiency class IE1 (reference converter), a CDM of efficiency
class IE2 has 25 % lower losses and a CDM of efficiency class
IE0 has 25 % higher losses.
Operating points for CDMs
Complete Drive Module (CDM) – determining the efficiency class
Establishing the efficiency classes of drive systems
(Power Drive Systems PDS)
What is possible for the individual systems, of course, also
applies to the entire electrical PDS (frequency converter plus
motor). Detailed comparisons are now possible at this level, too.
The reference values for the reference system provide clear
indications of the energy performance of the PDS.
Because targeted matching of the motor and CDM provides
additional potential for optimization in electrical drive systems,
it is especially important for the user to consider the entire drive
system.
For the efficiency class of a PDS, too, a specific load point is de-
fined. In this case, the reference point used is the 100/100 oper-
ating point (100 % motor stator frequency, 100 % torque).
Standard EN 50598-2 defines the relative losses of a PDS in
efficiency classes IES0 to IES2. With reference to the value of
a PDS of efficiency class IES1 (reference drive), a PDS of effi-
ciency class IES2 has 20 % lower losses and a PDS of efficiency
class IES0 has 20 % higher losses.
100
p
CDM
(0, 100)
p
CDM
(50, 100)
p
CDM
(90, 100)
p
CDM
(90, 100)
p
RCDM
(90, 100)
p
CDM
(90, 50)
p
CDM
(50, 50)
p
CDM
(0, 50)
p
CDM
(50, 25)
p
CDM
(0, 25)
50
%
25
0
0
Relative
torque current
100
IE0
IE0
IE1
IE1
IE2
IE2
100%
75%
50%
125%
90
50
%
Relative motor stator frequency
Reference value
(reference converter)
25% greater losses
than reference value
Reference value ±25%
25% lower losses than
reference value
Determination of the
efficiency classes IE0 to IE2
G_D011_EN_00468
© Siemens AG 2015