IEC 60034-30-1:2025

IEC 60034-30-1 ®
Edition 2.0 2025-12
INTERNATIONAL
STANDARD
COMMENTED VERSION
Rotating electrical machines -
Part 30-1: Efficiency classes of line operated AC motors (IE code)
ICS 29.160.01 ISBN 978-2-8327-0920-7
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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and symbols . 9
3.1 Terms and definitions. 9
3.2 Symbols . 10
4 Fields of application . 10
5 Efficiency. 11
5.1 Determination . 11
5.1.1 General . 11
5.1.2 Rated voltages, rated frequencies and rated power . 12
5.1.3 Auxiliary devices . 12
5.2 Rating . 13
5.3 Classification and marking . 13
5.3.1 General . 13
5.3.2 Efficiency classification . 13
5.3.3 Motors below IE1 efficiency . 13
5.3.4 Marking . 13
5.4 Nominal limits for efficiency classes IE1, IE2, IE3, IE4 and IE5 . 14
5.4.1 Nominal efficiency limits for IE1 . 14
5.4.2 Nominal efficiency limits for IE2 (see Tables 5 and 6) . 16
5.4.3 Nominal efficiency limits for IE3 (see Tables 7 and 8) . 18
5.4.4 Nominal efficiency limits for IE4 (see Tables 9 and 10) . 20
5.4.5 Nominal efficiency limits for IE5 . 22
5.4.6 Interpolation of nominal efficiency limits of intermediate rated output
powers for 50 Hz mains supply frequency . 24
5.4.7 Interpolation of nominal efficiency limits of intermediate rated powers
for 60 Hz mains supply frequency . 26
Annex A (informative) Nominal limits for efficiency class IE5 . 27
Annex A (informative) Nominal, rated (declared), minimum efficiency and tolerance . 27
Bibliography . 28
List of comments. 29

Figure A.1 – Nominal efficiency and tolerance . 27

Table 1 – Common motor technologies and their energy efficiency potential . 10
Table 2 – IE efficiency classification . 13
Table 3 – Nominal efficiency limits (%) for 50 Hz IE1 . 14
Table 4 – Nominal efficiency limits (%) for 60 Hz IE1 . 15
Table 5 – Nominal efficiency limits (%) for 50 Hz IE2 . 16
Table 6 – Nominal efficiency limits (%) for 60 Hz IE2 . 17
Table 7 – Nominal efficiency limits (%) for 50 Hz IE3 . 18
Table 8 – Nominal efficiency limits (%) for 60 Hz IE3 . 19
Table 9 – Nominal efficiency limits (%) for 50 Hz IE4 . 20
Table 10 – Nominal efficiency limits (%) for 60 Hz IE4 . 21
Table 11 – Nominal efficiency limits (%) for 50 Hz IE5 . 22
Table 12 – Nominal efficiency limits (%) for 60 Hz IE5 . 23
Table 13 – Interpolation coefficients for 0,12 kW to 0,74 0,55 kW . 24
Table 14 – Interpolation coefficients for 0,75 kW up to 200 kW . 25

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Rotating electrical machines -
Part 30-1: Efficiency classes of line operated AC motors (IE code)

FOREWORD
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This commented version (CMV) of the official standard IEC 60034-30-1:2025 edition 2.0 allows
the user to identify the changes made to the previous IEC 60034-30-1:2014 edition 1.0.
Furthermore, comments from IEC TC 2 experts are provided to explain the reasons of the most
relevant changes, or to clarify any part of the content.
A vertical bar appears in the margin wherever a change has been made. Additions are in green
text, deletions are in strikethrough red text. Experts' comments are identified by a blue-
background number. Mouse over a number to display a pop-up note with the comment.
This publication contains the CMV and the official standard. The full list of comments is available
at the end of the CMV.
IEC 60034-30-1 has been prepared by IEC Technical Committee 2: Rotating machinery. It is an
International Standard.
This second edition of IEC 60034-30-1 cancels and replaces the first edition of IEC 60034-30-1
published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Table 1 in Clause 4 revised and IE5 efficiency introduced.
b) New efficiency tables (Table 11 and Table 12) added for IE5 nominal efficiency limits.
c) Table 13 for interpolation coefficients revised based on IE5 limits and the coefficients limited
from 0,12 kW to 0,75 kW 0,12 kW to 0,55 kW. A linear interpolation shall be applied to obtain
minimum efficiency between 0,55 kW and 0,75 kW.
d) Annex A revised and added Figure A.1 showing nominal, rated, minimum efficiency and
tolerance.
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2235/FDIS 2/2279/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard are English and French.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
NOTE A table of cross-references of all IEC TC 2 publications can be found on the IEC TC 2 dashboard on the IEC
website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
This first part of the IEC 60034-30 series, IEC 60034-30-1, provides for the global harmonization
of energy efficiency classes of electric motors. It deals with all kinds of electric motors that are
rated for line operation (including starting at reduced voltage). This includes all either 50 Hz or
60 Hz, or both single- and three-phase low voltage induction motors, regardless of their rated
voltage and frequency, as well as line-start permanent-magnet synchronous motors.
The second part of this standard series (IEC 60034-30-2) will be is prepared for motors rated
for variable voltage and frequency supply, such as synchronous motors. The second part will
also provide for harmonic voltage losses in motors capable of line operation when fed by
frequency converters.
IEC 60034-30-1 widens the product range covered in the first edition of IEC 60034-30
significantly. The power range has been expanded (starting at 0,12 kW and ending at 1 000
kW). All technical constructions of electric motors are covered as long as they are rated for on-
line operation and not just three-phase, cage-induction motors as in the first edition.
The IE4 class is newly included in this standard. The informative definition of IE4, which was
previously included in IEC/TS 60034-31:2010, is therefore outdated.
The new class IE5 is not yet defined in detail but is envisaged for potential products in a future
edition of the standard.
This second edition of IEC 60034-30-1 introduces a new efficiency class, IE5. It is important to
note that International Energy efficiency (IE) class definition is generally independent of the
output power – frame size assignment. As standardized dimensions and outputs in the
IEC 60072 series are based on today's technology (up to IE4), it can be challenging to
implement highest IE classes according to existing frame sizes.
It is possible that motors, especially those with lower output power ratings, are designed and
manufactured in one frame size bigger than frame size assigned in IEC 60072-1 to reach IE4
and IE5 efficiency levels. 1
For a given power and frame size it is generally easier to achieve a higher motor efficiency
when the motor is designed for and operated directly on-line with a 60 Hz supply frequency
rather than on 50 Hz as explained in Note 1.
NOTE 1 As the utilization and size of motors are related to torque rather than power the theoretical power of single-
speed motors increases linearly with supply frequency (and hence with speed), i.e. by 20 % from 50 Hz to 60 Hz.
I R winding-losses are dominant especially in small and medium sized induction motors. They basically remain
constant at 50 Hz and 60 Hz as long as the torque is kept constant. Although windage, friction and iron losses
increase with frequency, they play a minor role especially in motors with a number of poles of four and higher.
Therefore, at 60 Hz, the losses increase less than the 20 % power increase when compared to 50 Hz and
consequently, the efficiency is improved.
In practice, both 60 Hz and 50 Hz power designations of single-speed motors have to usually conform to standard
power levels in accordance with IEC 60072-1 and local standards such as EN 50347. Therefore, an increased rating
of motor power by 20 % is not always possible. However, the general advantage of 60 Hz still applies when the motor
design is optimized for the respective supply frequency rather than just re-rated.
The difference in efficiency between 50 Hz and 60 Hz varies with the number of poles and the size of the motor. In
general, the 60 Hz efficiency of three-phase, cage-induction motors in the power range from 0,75 kW up to 375 kW
is between 2,5 percentage points to less than 0,5 percentage points greater when compared to the 50 Hz efficiency.
Only large 2-pole motors may can experience a reduced efficiency at 60 Hz due to their high share of iron, windage
and friction losses.
It is not expected that all manufacturers will produce motors for all efficiency classes, nor all
ratings of a given class.
Users should select the efficiency class in accordance with a given application depending on
the actual operating hours. It may not be energy efficient to select motors of a high efficiency
class for intermittent or short time duty due to increased inertia and start-up losses.
Users should dimension motors to be suitable for the intended applications based on the load
profile, operating hours in order to maximize energy savings considering most energy efficient
solutions in addition that all other requirements set by the application are covered. It is possible
that selecting motors of a high efficiency class for intermittent or short time duty due to
increased inertia and start-up losses is not energy efficient. 2
NOTE 2 The application guide IEC TS 60034-31:2010 gives further information on useful applications of
high-efficient electric motors.
In order to achieve a significant market share it is essential for high-efficiency motors to meet
national or regional standards for assigned powers in relation to mechanical dimensions (such
as frame-size, flanges). IEC 60072-1 defines the relationship between mechanical dimensions
and rated output as well. There are a number of several national or regional frame assignment
standards (EN 50347, JIS C 4212, NBR 17094, NEMA MG13, SANS 1804 and others) but there
is no IEC standard). As this document (IEC 60034-30-1) defines energy efficiency classes
independent of dimensional constraints, it may not be is possible in all markets to produce it is
possible that producing motors with higher efficiency classes, whilst maintaining the mechanical
dimensions of national or regional standards, will not be feasible in all markets.
To meet the demands of higher energy efficiency classes, the designs of components and
equipment and the selection of efficient materials should not be overlooked. There can be a
need to use more materials such as electrical steel, copper and aluminium to enable the design
of high efficiency motors. Consequently, the develop IE5 class motors using the same frames
sizes as IE4 class motors is not always possible. The higher efficiency class motors are likely
to be heavier. This will drive the need to re-design the application of the high efficiency motor. 3
IE codes are not limited only to motors but may be and are used to classify other components
such as frequency converters and gearboxes (IEC 61800-9-2). The same standard defines also
IES classes to combinations of components (such as power drive systems).
However, it is anticipated that other components are rated with a comparable system: IE1
meaning low efficiency up to IE5 meaning the highest efficiency.
Combinations of components (such as power drive systems) will need a combined efficiency
rating. That rating should not be an IE code in order to avoid confusion. It will be defined in
other IEC standards.
The efficiency levels in this document for 50 Hz and 60 Hz are not always entirely consistent
across all numbers of poles and over the whole power range.
NOTE 3 The efficiency levels for 60 Hz motors were assigned for compatibility with U.S. and North American legal
requirements.
NOTE 4 The efficiency levels for 50 Hz motors between 0,75 kW and 375 kW remain unchanged for compatibility
with European legal requirements. 4
1 Scope
This part of IEC 60034 specifies efficiency classes for single-speed electric motors that are
rated in accordance with IEC 60034-1 or IEC 60079-0 and are rated for operation on a
sinusoidal either 50 Hz or 60 Hz, or both voltage supply.
The motors within this document:
from 0,12 kW to 1 000 kW;
– have a rated power P
N
– have a rated voltage U above from 50 V up to and including 1 000 V;
N
– have 2, 4, 6 or 8 poles;
– are capable of continuous operation at their rated power with a temperature rise within the
specified insulation temperature class;
NOTE 1 Most motors covered by this document are rated for duty type S1 (continuous duty). However, some
motors that are rated for other duty cycles are still capable of continuous operation at their rated power, and
these motors are also covered by this document.
– are marked with any ambient temperature within the range of –20 –30 °C 5 to +60 °C;
NOTE 2 The rated efficiency and efficiency classes are based on 25 °C ambient temperature in accordance
with IEC 60034-2-1.
NOTE 3 Motors exclusively rated for temperatures outside the range – 20 –30 °C and +60 °C are considered
to be of special construction and are consequently excluded from this document.
NOTE 4 Smoke extraction motors with a temperature class of up to and including 400 °C are covered by this
document.
– are marked with an altitude up to 4 000 m above sea level.
NOTE 5 The rated efficiency and efficiency class are based on a rating for altitudes up to 1 000 m above sea
level.
This document establishes a set of limit nominal efficiency values based on supply frequency,
number of poles and motor output power. No distinction is made between motor technologies,
supply voltage or motors with increased insulation designed specifically for converter operation
even though these not all motor technologies may not all be are capable of reaching the higher
efficiency classes (see Table 1). This makes different motor technologies fully comparable with
respect to their energy efficiency potential.
NOTE 6 Regulators should consider the above constraints when assigning national minimum energy-efficiency
performance standards (MEPS) with respect to any particular type of motor. 6
The efficiency of power-drive systems is not covered by this document. In particular, Motor
losses due to harmonic content of the supply voltage, losses in cables, filters and frequency-
converters, are not covered.
Motors with flanges, feet and/or shafts with mechanical dimensions different from IEC 60072-1
are covered by this document.
Geared motors are covered by this document including those incorporating non-standard shafts
and flanges.
Totally enclosed air-over machines (TEAO, IC418), i.e. totally enclosed frame-surface cooled
machines intended for exterior cooling by a ventilating means external to the machine, are
covered by this document. Efficiency testing of such motors may can be performed with the fan
removed and the cooling provided by an external blower with a similar airflow rate as the original
fan.
This document does not apply to the following:
– Single-speed motors with 10 or more poles or multi-speed motors.
– Motors with mechanical commutators (such as DC motors).
– Motors completely integrated into a machine (for example pump, fan and compressor) that
cannot be practically tested separately from the machine even with provision of a temporary
end-shield and drive-end bearing. This means the motor shall: a) shares common
components (apart from connectors such as bolts) with the driven unit (for example, a shaft
or housing) and b) is not be designed in such a way as to enable the motor to be separated
from the driven unit as an entire motor that can operate independently of the driven unit.
That is, for a motor to be excluded from this document, the process of separation shall
render the motor inoperative.
– Motors with integrated frequency converters (compact drives) when the motor cannot be
tested separately from the converter. Energy efficiency classification of compact drives shall
be is based on the complete product (PDS, ie. Power Drive System) and will be is defined
in a separate standard IEC 61800-9-2.
NOTE 6 A motor is not excluded when the motor and frequency-converter can be separated, and the motor can
be tested independently of the converter.
– Brake motors when the brake is an integral part of the inner motor construction and can
neither be removed nor supplied by a separate power source during the testing of motor
efficiency.
NOTE 7 Brake motors with a brake coil that is integrated into the flange of the motor are covered as long as it
is possible to test motor efficiency without the losses of the brake (for example by dismantling the brake or by
energizing the brake coil from a separate power source).
When the manufacturer offers a motor of the same design with and without a brake the test
of motor efficiency may can be done on a motor without the brake. The determined efficiency
may then be used as the rating of both motor and brake motor for a motor with or without
the brake.
– Submersible motors specifically designed to operate wholly immersed in a liquid.
– Smoke extraction motors with a temperature class above 400 °C.
2 Normative references
The following documents are referred to in the text in such a way that some or all their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60034-1, Rotating electrical machines - Part 1: Rating and performance
IEC 60034-2-1, Rotating electrical machines - Part 2-1: Standard methods for determining
losses and efficiency from tests (excluding machines for traction vehicles)
IEC/TS 60034-2-3, Rotating electrical machines – Part 2-3: Specific test methods for
determining losses and efficiency of converter-fed AC induction motors
IEC 60034-6, Rotating electrical machines – Part 6: Methods of cooling (IC Code)
IEC/TS 60034-25, Rotating electrical machines – Part 25: Guidance for the design and
performance of a.c. motors specifically designed for converter supply
IEC 60038, IEC standard voltages
IEC 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements 7
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
single-speed motor
motor rated either 50 Hz or 60 Hz, or both for direct-on-line operation
Note 1 to entry: Single-speed motors may be capable of frequency converter operation with variable speed.
3.1.2
multi-speed motor
motor rated either 50 Hz or 60 Hz, or both for direct-on-line operation that has multiple windings
or a switchable winding to provide two or more different number of poles with different
synchronous speeds
3.1.3
variable speed motor 8
motor rated for a speed range and supplied by voltage of variable amplitude and frequency
3.1.3
brake motor
motor equipped with an electro-mechanical brake unit operating directly on the motor shaft
without couplings
3.1.4
geared motor
motor equipped with an integral gearbox without couplings (i.e. the first gear wheel is fixed to
the motor shaft)
3.1.6
pump motor 9
motor directly attached to a pump without couplings (i.e. the impeller is fixed to the motor shaft)
3.1.7
average efficiency 10
average efficiency value for a motor population of the same design and rating
3.1.5
nominal efficiency
minimum rated 11 efficiency value required to meet a certain efficiency class according to the
efficiency tables in this document
3.1.6
rated efficiency
efficiency value assigned by the manufacturer, equal to the nominal efficiency value or higher
3.2 Symbols
η is the nominal efficiency, %
n
η is the rated efficiency, %
N
f is the rated frequency, Hz
N
–1
n is the rated speed, min
N
P is the rated power, kW
N
T is the rated torque, Nm
N
U is the rated voltage, V
N
4 Fields of application
Table 1 gives information on line-start and energy efficiency potential of various commonly used
motor technologies for motors in direct-on-line start and operation.
Not all motor technologies are able to reach all efficiency classes nor can motors for all
efficiency classes or sizes be produced or operated in an economically feasible way. Therefore,
regulators are asked to consider the following constraints when assigning minimum energy
efficiency performance standards (MEPS).
are considered to be state of present technology and are
Motors marked with "Yes" in Table 1
consequently suitable for consideration in mandatory requirements in legislation state-of-the-
art based on present technology and availability of materials for industrial products and can be
subject to regulatory requirements.
Table 1 – Common motor technologies and their energy efficiency potential
Motor type IE1 IE2 IE3 IE4 IE5
Three-phase cage- Random wound Yes No
Yes Yes Yes
rotor induction windings (all Difficult Very
a
motors (ASM) enclosures, all
Difficult
ratings)
Form wound Yes Yes Difficult No No
windings; IP2x
(open motors)
Form wound Yes Yes Yes Difficult No
windings; IP4x and
above
Three-phase wound-rotor induction motors Yes Yes Yes Difficult No
Single-phase Start capacitor Difficult No No No No
induction motors
Run capacitor Yes Difficult No No No
Start and run
Yes Difficult No No No
capacitor
Split-phase Difficult No No No No
Synchronous motors Line-start Yes Yes Yes Difficult No
permanent-magnet Very
a
Difficult
(LSPM )
b
synchronous
a
It is possible that the design and frame size can be different for IE5 motors, especially for smaller size of
motors, in comparison with existing designs with lower efficiency (IE2, IE3 and IE4) levels.
ab
Line-start permanent-magnet synchronous motors have limitations on their line-start capabilities with respect
to torque and external inertia and may not be are not suitable for all types of applications.

Motor type IE1 IE2 IE3 IE4 IE5
NOTE 1 With regard to the IE levels, "Yes" means the efficiency class is achievable with present technology
(although in some cases it may not be is not economical); "No" means the efficiency class is not generally
achievable with present technology; "Difficult" means that the energy efficiency level may can be achieved with
present technology for some but not all power ratings and the standardized frame size may can be exceeded.
"Line-start" means the capability of the motor to start direct on-line (Design N of IEC 60034-12 for single-speed,
three-phase cage induction motors) without the need for a frequency converter.
NOTE 2 It may can be difficult to develop motors for efficiency classes IE3 IE4 and above within the local
power/frame size standards (such as NBR 17094-1 or EN 50347).
NOTE 3 It is expected that motors for efficiency class IE5 will be covered in part 2 of this standard.
NOTE 4 The energy efficiency potential of motor technologies regarding IE5 classification will be revised after
the IE5 classification has been defined.

Motors covered by this document may be used in variable-speed drive applications (see IEC/TS
60034-25). In such applications the actual efficiency of the motor is lower than the rated
efficiency due to increased losses from the harmonic-voltage content of the power supply. For
efficiency testing see IEC/TS 60034-2-3.
The energy efficiency classification of motors in this document is related to the losses at
sinusoidal power supply only.
It is possible that the following motors may not be are not able to reach the higherst efficiency
classes specifications (IE3 and above):
– motors with cooling methods other than IC0Ax, IC1Ax, IC2Ax, IC3Ax or IC4Ax according to
IEC 60034-6;
– motors built for a restricted space (high-output design, i.e. smaller frame sizes than usual
in national standards);
– motors specifically built for operation in explosive environments according to IEC 60079-0
(due to safety requirements and possible design constraints of explosion proof motors such
as increased air gap, reduced starting current, enhanced sealing);
– motors for special requirements of the driven machine beyond the requirements of the
IEC 60034 series of standards (such as motors for heavy starting duty, special torque
stiffness and/or breakdown torque characteristics, large number of start/stop cycles, very
low rotor inertia);
– motors for special characteristics of the grid supply beyond the requirements of the
IEC 60034 series of standards (such as motors with limited starting current, increased
tolerances of either the voltage and/or frequency, or both of them);
– motors with liquid cooling on account of their higher power density compared with air cooled
motors of the same frame size;
– smoke extraction motors with a temperature class higher than 300 °C.
5 Efficiency
5.1 Determination
5.1.1 General
This document deals with single-speed motors operated on-line. Motors operated by frequency-
converters may have higher losses as compared to on-line (sinusoidal) power supply due to the
harmonic voltage content (for details see IEC/TS 60034-25). They are covered in part two of
this standard series.
To make efficiency class ratings comparable between different motor technologies according
to this document, all tests shall be performed on sinusoidal voltage.
Efficiency and losses shall be tested in accordance with the preferred method of the individual
motor type as given in IEC 60034-2-1 and corrected to the ambient temperature of 25 °C. 12
5.1.2 Rated voltages, rated frequencies and rated power
The rated efficiency shall be determined at rated power P , rated voltage U and rated
N N
frequency f .
N
Motors rated for an extended voltage tolerance (for example 400 V ± 10 % according to
IEC 60038) shall be assigned a single rated efficiency, i.e. the extended tolerance shall be
disregarded.
Motors rated for an extended voltage range (for example 380 V – 440 V) shall fulfil the assigned
rated efficiency in the whole voltage range 13. Motors with rated voltage/frequency
combinations of the same magnetic flux and power, for example 230 V/400 V (delta/star) or
230 V/460 V (double-star/star or double-delta/delta), shall have only one rated efficiency and
efficiency class (IE code) per voltage/frequency combination of same flux and power.
Motors with more than one rated voltage/frequency/power combination should shall be assigned
a rated efficiency and a rated efficiency class (IE code) for each rated voltage/frequency/power
combination.
However, as a minimum the lowest efficiency value and the associated IE code (of all rated
voltage/frequency/power combinations) for both 50 Hz and 60 Hz ratings shall always be
printed on the rating plate.
All efficiency values and IE codes shall be available in the product documentation (catalogue
or operating instructions).
NOTE For example, in Japan the rating combination "200 V/50 Hz – 200 V/60 Hz – 220 V/60 Hz" is commonly used
for single-speed motors and in Europe the rating combination "380 V/50 Hz – 400 V/50 Hz – 415 V/50 Hz –
460 V/60 Hz" is sometimes used. For these examples there will be three or four efficiency ratings and there may can
be several different IE codes.
5.1.3 Auxiliary devices
Some electric motors covered by this document may be equipped with auxiliary devices such
as shaft seals, external fans, mechanical brakes, back-stops and unidirectional bearings, speed
sensors, tacho-generators in various combinations.
However, as long as if these auxiliary devices are not an integral part of the basic motor design,
the determination of efficiency in all possible combinations is not practical. Tests for efficiency
of such modified standard motors shall be performed on basic motors with original cooling
without auxiliary devices installed.
The losses of a separately driven fan are to be included in the efficiency determination
procedure when the external fan is an integral part of the basic motor construction. When the
external fan is just an optional add-on to a mass-produced motor, which normally carries a
shaft-mounted fan, the losses of the basic motor (with the shaft-mounted fan) can be used.
Angular-contact bearings (thrust bearings) for vertical mounted motors may be replaced by
standard bearings during efficiency testing. Such motors may be tested horizontally.
Some types of motors (such as geared motors, pump motors and others) Most motors are
equipped with shaft seals to prevent ingress of oil or water into the motor. External seals shall
be removed for efficiency testing. This applies only to seals that are accessible from the outside
without dismantling of the motor (dismantling of the fan cover and the fan is accepted).
Electro-mechanical brakes shall be removed during testing of motor efficiency. When the motor
construction prohibits a removal of the brake, the brake-coil shall be energized from a separate
power source and the energy consumption of the brake-coil shall be disregarded in the
calculation of motor efficiency.
5.2 Rating
The efficiency declared by the manufacturer on the rating plate (rated efficiency) shall be
greater or equal to the nominal efficiency as defined in this document according to the efficiency
class (IE code) on the rating plate.
The full-load efficiency of any motor, when tested at rated voltage and rated frequency shall not
be less than the rated-/classification efficiency minus the tolerance of the total losses in
accordance with IEC 60034-1.
It is recommended to report efficiencies at 50 %, 75 % and full load 100 % power in the product
documentation. For the purpose of this document only the efficiency at rated power applies.
Variations in materials, manufacturing processes and testing result in motor-to-motor efficiency
variations for a given motor design. The full-load efficiency for a large population of motors of
a single design is not a unique value but rather a band of efficiency. Therefore, the energy
efficiency limits given in this document are nominal.
See Figure A.1 in Annex A for the clarification of tolerances and rated (declared), nominal and
minimum allowed (guaranteed) efficiency. 14
5.3 Classification and marking
5.3.1 General
The designation of the energy efficiency class consists of the letters "IE" (short for International
Energy efficiency class), directly followed by a numeral representing the classification according
to Table 2.
5.3.2 Efficiency classification
Table 2 – IE efficiency classification
Designation Definition
IE1 Motors with a rated full-load efficiency equal to or exceeding the limits listed in 5.4.1.
IE2 Motors with a rated full-load efficiency equal to or exceeding the limits listed in 5.4.2.
IE3 Motors with a rated full-load efficiency equal to or exceeding the limits listed in 5.4.3
IE4 Motors with a rated full-load efficiency equal to or exceeding the limits listed in 5.4.4.
IE5 Envisaged for a future edition of this standard. See Annex A.
Motors with a rated full-load efficiency equal to or exceeding the limits listed in 5.4.5. 15

5.3.3 Motors below IE1 efficiency
Some motors have rated efficiencies below the limits given in Table 3 and Table 4. No efficiency
marking of these such motors below IE1 efficiencies shall be are required.
5.3.4 Marking
The rated efficiency and the IE code shall be durably marked on the rating plate, for example
"IE2 – 84,0 %".
5.4 Nominal limits for efficiency classes IE1, IE2, IE3, IE4 and IE5
NOTE Shaded areas in the tables indicate changes compared to the previous edition of this standard.
5.4.1 Nominal efficiency limits for IE1
Table 3 and Table 4 show the nominal efficiency limits for IE1.
Table 3 – Nominal efficiency limits (%) for 50 Hz IE1
Number of poles/synchronous speed
P
N
–1
min
kW
2/3000 4/1500 6/1000 8/750
0,12 45,0 50,0 38,3 31,0
0,18 52,8 57,0 45,5 38,0
0,20 54,6 58,5 47,6 39,7
0,25 58,2 61,5 52,1 43,4
0,37 63,9 66,0 59,7 49,7
0,40 64,9 66,8 61,1 50,9
0,55 69,0 70,0 65,8 56,1
0,75 72,1 72,1 70,0 61,2
1,1 75,0 75,0 72,9 66,5
1,5 77,2 77,2 75,2 70,2
2,2 79,7 79,7 77,7 74,2
3 81,5 81,5 79,7 77,0
4 83,1 83,1 81,4 79,2
5,5 84,7 84,7 83,1 81,4
7,5 86,0 86,0 84,7 83,1
11 87,6 87,6 86,4 85,0
15 88,7 88,7 87,7 86,2
18,5 89,3 89,3 88,6 86,9
22 89,9 89,9 89,2 87,4
30 90,7 90,7 90,2 88,3
37 91,2 91,2 90,8 88,8
45 91,7 91,7 91,4 89,2
55 92,1 92,1 91,9 89,7
75 92,7 92,7 92,6 90,3
90 93,0 93,0 92,9 90,7
110 93,3 93,3 93,3 91,1
132 93,5 93,5 93,5 91,5
160 93,8 93,8 93,8 91,9
200 up to 1 000 94,0 94,0 94,0 92,5
Number of poles/synchronous speed
P
N
–1
min
kW
2/3000 4/1500 6/1000 8/75
...