SIST EN IEC 60034-2-3:2024

SLOVENSKI STANDARD
01-september-2024
Električni rotacijski stroji - 2-3. del: Posebne preskusne metode za ugotaljanje
izgub in izkoristkov izmeničnih motorjev napajanih s pretvorniki (IEC 60034-2-
3:2024)
Rotating electrical machines - Part 2-3: Specific test methods for determining losses and
efficiency of converter-fed AC motors (IEC 60034-2-3:2024)
Drehende elektrische Maschinen – Teil 2-3: Besondere Verfahren zur Bestimmung der
Verluste und des Wirkungsgrades von umrichtergespeisten Wechselstrommaschinen
(IEC 60034-2-3:2024)
Machines électriques tournantes - Partie 2-3: Méthodes d'essai spécifiques pour la
détermination des pertes et du rendement des moteurs à courant alternatif alimentés par
convertisseur (IEC 60034-2-3:2024)
Ta slovenski standard je istoveten z: EN IEC 60034-2-3:2024
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60034-2-3

NORME EUROPÉENNE
EUROPÄISCHE NORM April 2024
ICS 29.160.01 Supersedes EN IEC 60034-2-3:2020
English Version
Rotating electrical machines - Part 2-3: Specific test methods for
determining losses and efficiency of converter-fed AC motors
(IEC 60034-2-3:2024)
Machines électriques tournantes - Partie 2-3: Méthodes Drehende elektrische Maschinen - Teil 2-3: Besondere
d'essai spécifiques pour la détermination des pertes et du Verfahren zur Bestimmung der Verluste und des
rendement des moteurs à courant alternatif alimentés par Wirkungsgrades von umrichtergespeisten
convertisseur Wechselstrommaschinen
(IEC 60034-2-3:2024) (IEC 60034-2-3:2024)
This European Standard was approved by CENELEC on 2024-04-16. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60034-2-3:2024 E

European foreword
The text of document 2/2164/FDIS, future edition 2 of IEC 60034-2-3, prepared by IEC/TC 2 "Rotating
machinery" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-01-16
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-04-16
document have to be withdrawn
This document supersedes EN IEC 60034-2-3:2020 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60034-2-3:2024 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC/TS 60034-25:2022 NOTE Approved as CLC IEC/TS 60034-25:2024 (not modified)
IEC/TS 60034-31:2021 NOTE Approved as CLC IEC/TS 60034-31:2024 (not modified)
IEC 61800-2:2021 NOTE Approved as EN IEC 61800-2:2021 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of 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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60034-1 - Rotating electrical machines - Part 1: EN 60034-1 -
Rating and performance
IEC 60034-2-1 - Rotating electrical machines - Part 2-1: EN IEC 60034-2-1 -
Standard methods for determining
losses and efficiency from tests
(excluding machines for traction
vehicles)
IEC 60034-30-1 - Rotating electrical machines - Part 30- EN 60034-30-1 -
1: Efficiency classes of line operated
AC motors (IE code)
IEC/TS 60034-30-2 - Rotating electrical machines - Part 30- CLC IEC/TS 60034-30-2 -
2: Efficiency classes of variable speed
AC motors (IE code)
IEC 61000-2-4 - Electromagnetic compatibility (EMC) - EN 61000-2-4 -
Part 2-4: Environment - Compatibility
levels in industrial plants for low-
frequency conducted disturbances
IEC 61800-9-2 - Adjustable speed electrical power drive EN 61800-9-2 -
systems - Part 9-2: Ecodesign for
power drive systems, motor starters,
power electronics and their driven
applications - Energy efficiency
indicators for power drive systems and
motor starters
IEC 60034-2-3 ®
Edition 2.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Rotating electrical machines –

Part 2-3: Specific test methods for determining losses and efficiency of

converter-fed AC motors
Machines électriques tournantes –

Partie 2-3: Méthodes d'essai spécifiques pour la détermination des pertes et du

rendement des moteurs à courant alternatif alimentés par convertisseur

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.160.01  ISBN 978-2-8322-8172-7

– 2 – IEC 60034-2-3:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Symbols and abbreviated terms . 10
5 Basic requirements . 11
5.1 Instrumentation . 11
5.1.1 General . 11
5.1.2 Power analyser and transducers . 11
5.1.3 Mechanical output of the motor . 12
5.2 Converter set-up . 12
5.2.1 General . 12
5.2.2 Comparable converter set-up for rated voltages up to 1 kV . 12
5.2.3 Converters with rated voltages above 1 kV . 13
5.2.4 Testing with other converters . 13
5.3 Ambient temperature during testing . 13
5.4 State of the motor under test. 13
6 Test method for the determination of the efficiency of converter-fed motors . 14
6.1 Selection of determination method . 14
6.2 Method 2-3-A – Direct measurement of input and output . 14
6.2.1 Test set-up . 14
6.2.2 Test procedure . 14
6.2.3 Efficiency determination . 15
6.2.4 Measurement at seven standardized operating points . 15
6.3 Method 2-3-B – Summation of losses with determination of additional high
frequency loss at converter supply at no-load operation . 16
6.3.1 General . 16
6.3.2 Test set-up . 16
6.3.3 Test procedure . 16
6.3.4 Efficiency determination . 16
6.4 Method 2-3-C – Alternate Efficiency Determination Method (AEDM) . 17
6.5 Method 2-3-D – Determination of efficiency by calculation . 17
7 Interpolation of motor losses at any operating point . 17
7.1 General . 17
7.2 Definitions . 18
7.3 Interpolation and extrapolation of relative losses at any operating point . 18
7.4 Determination of interpolation coefficients . 19
7.4.1 General . 19
7.4.2 Analytical determination . 20
7.4.3 Numerical determination . 21
7.5 Alternate operating points to determine interpolation coefficients . 21
7.6 Optional determination of interpolation error . 23
Annex A (informative) Losses of AC motors . 24
A.1 General . 24
A.2 Stator and rotor winding I R losses P (P + P ) . 24
LSR LS LR
IEC 60034-2-3:2024 © IEC 2024 – 3 –
A.3 Iron losses (P ) . 25
Lfe
A.4 Additional load losses (P ) . 25
LL
A.5 Friction and windage losses (P ) . 25
Lfw
A.6 Additional high frequency losses (P ) . 26
LHL
Annex B (informative) Exemplary determination of losses and efficiency at various

load points . 27
B.1 General . 27
B.2 Determination of the interpolation coefficients . 27
B.3 Calculation of losses and efficiency for certain operating points . 28
Annex C (informative) Loss interpolation for different winding connections . 30
Annex D (informative) Examples for additional load points for the numerical
interpolation procedure . 32
Bibliography . 34

Figure 1 – Standardized operating points . 20
Figure C.1 – Connection Y or D, ranges a and b . 30
Figure C.2 – Connection Y ► D, ranges a and b . 31
Figure C.3 – Connection Y ► YY, range a . 31
Figure D.1 – Example for additional load points mainly in the over speed area . 32
Figure D.2 – Example for additional load points in the overload and over speed area . 33

Table 1 – Preferred test methods . 14
Table 2 – Other test methods . 14
Table 3 – Normative operating points . 20
Table 4 – Non-normative alternate operating points . 22
Table A.1 – Recommended split of windage and friction losses for IC 411 self-
ventilated motors . 26
Table B.1 – Name plate data. 27
Table B.2 – Reference values . 27
Table B.3 – Losses for the 7 operating points . 28
Table B.4 – Interpolation coefficients . 28
Table B.5 – User-defined operating points . 29
Table B.6 – Calculated losses for the user-defined operating points . 29

– 4 – IEC 60034-2-3:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –

Part 2-3: Specific test methods for determining losses and
efficiency of converter-fed AC motors

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60034-2-3 has been prepared by IEC technical committee 2: Rotating machinery. It is an
International Standard.
This second edition cancels and replaces the first edition of IEC 60034-2-3 published in 2020.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Harmonization of requirements and procedures with IEC 60034-2-1.
b) Extension of the interpolation procedure to the field weakening range.

IEC 60034-2-3:2024 © IEC 2024 – 5 –
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2164/FDIS 2/2179/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 is English.
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.
A list of all parts in the IEC 60034 series, published under the general title Rotating electrical
machines, can be found 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.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC 60034-2-3:2024 © IEC 2024
INTRODUCTION
The objective of this document is to define test methods for determining total losses including
additional high frequency motor losses and efficiency of converter-fed motors. Additional high
frequency losses appear in addition to the losses on nominally sinusoidal power supply as
determined by the methods of IEC 60034-2-1. Results determined according to this document
are intended to allow comparison of losses and efficiency of different motors if fed by
converters.
Furthermore, the document gives seven standardized operating points to characterize the
development of losses and efficiency across the whole torque/speed range. An interpolation
procedure is provided to calculate losses and efficiency at any operating point (torque, speed).
In power-drive systems (PDS), the motor and the frequency converter are often manufactured
by different suppliers. Motors of the same design are produced in large quantities. They may
be operated from the grid or from frequency converters of many different types, supplied by
many different manufacturers. The individual converter properties (switching frequency, DC link
voltage level, etc.) will also influence the system efficiency. As it is impractical to determine
motor losses for every combination of motor, frequency converter, connection cable, output
filter and parameter settings, this document describes a limited number of approaches,
depending on the voltage level and the rating of the motor under test.
The losses determined with the comparable converter as defined in this document are not
intended to represent the losses in the final application. They provide, however, an objective
basis for comparing different motor designs with respect to suitability for converter operation.
In general, if fed from a converter, motor losses are higher than during operation on a nominally
sinusoidal system, even though the converter normally enables vast energy savings overall on
system level, when the motor and the load application can be operated with variable speed.
The additional high frequency losses depend on the harmonic spectrum of the impressed
converter output quantity (either current or voltage) which is influenced by its circuitry and
control method. For further information, see IEC TS 60034-25.
It is not the purpose of this document to define test procedures either for power drive systems
or for frequency converters alone.
Comparable converter
Latest experience and theoretical analysis have shown that the additional high frequency motor
losses generally do not increase much with torque for a specific speed. The methods in this
document are mainly based on supplies from converters with pulse width modulation (PWM).
With respect to these types of converters and the growing need for verification of compliance
with national energy efficiency regulations, this document defines a so-called comparable
converter for testing of low voltage motors.
In principle, the comparable converter is a voltage source with a typical high frequency harmonic
content supplying the motor under test. It is not applicable to medium voltage motors.

IEC 60034-2-3:2024 © IEC 2024 – 7 –
Limitations for the application of the comparable converter
The test method with the comparable converter described herein is a standardized method
intended to give comparable efficiency figures for standardized test conditions. A motor ranking
with respect to suitability for converter operation may be derived, but it is not equivalent to
determining of the actual motor losses for operation with a specific converter which requires a
test of the whole power drive system (PDS) with the specific converter used in the final
application.
Deviations are also expected for motors driven by multi-level voltage source or current source
converters where the additional high frequency motor losses differ much more depending on
speed and load than for two-level voltage source converters. Hence the determination of losses
and efficiency should use procedures where the motor is operated together with the same
converter with which it is driven in service.
Another option is the determination of the additional high frequency motor losses by calculation.
If this is requested, then the pulse pattern of the converter is required. Such procedures are not
part of this document.
– 8 – IEC 60034-2-3:2024 © IEC 2024
ROTATING ELECTRICAL MACHINES –

Part 2-3: Specific test methods for determining losses and
efficiency of converter-fed AC motors

1 Scope
This part of IEC 60034 specifies test methods and an interpolation procedure for determining
losses and efficiencies of converter-fed motors. The motor is then part of a variable frequency
power drive system (PDS) as defined in IEC 61800-9-2.
Applying the approach of the comparable converter, the motor efficiency determined by use of
this document is applicable for comparison of different low voltage motor designs only. The
comparable converter approach is not applicable to medium voltage motors.
This document also specifies procedures to determine motor losses at any load point (torque,
speed) within the constant flux range (constant torque range, base speed range), the field
weakening range and the overload range based on determination of losses at seven
standardized load points. This procedure is applicable to any variable speed AC motor
(induction and synchronous) rated according to IEC 60034-1 for operation on a variable
frequency and variable voltage power supply.
2 Normative references
The following documents are referred to in the text in such a way that some or all of 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 60034-30-1, Rotating electrical machines – Part 30-1: Efficiency classes of line operated
AC motors (IE code)
IEC TS 60034-30-2, Rotating electrical machines – Part 30-2: Efficiency classes of variable
speed AC motors (IE-code)
IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2-4: Environment – Compatibility
levels in industrial plants for low-frequency conducted disturbances
IEC 61800-9-2, Adjustable speed electrical power drive systems – Part 9-2: Ecodesign for
power drive systems, motor starters, power electronics and their driven applications – Energy
efficiency indicators for power drive systems and motor starters

IEC 60034-2-3:2024 © IEC 2024 – 9 –
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60034-1,
IEC 60034-2-1 as well as 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
additional high frequency losses
additional high frequency losses are produced in the motor by the non-sinusoidal voltage and
current waveforms generated by the converter and are in addition to the losses of iron, friction
and windage, rotor winding, stator winding and additional load loss (fundamental losses)
3.2
constant flux range
speed range from standstill up to the highest speed where the motor can be supplied with a
voltage that changes in proportion to the speed so that the magnetic flux remains constant
(constant ratio U/f). Within the constant flux range, the maximum motor torque is constant
(constant torque range), if constant flux control is used. Constant flux range can also be called
base speed range.
3.3
field weakening range
speed range above the speed where the motor can be supplied with a voltage that changes in
proportion to the speed. Therefore, the magnetic flux in this speed range is reduced in relation
to constant flux range.
3.4
fundamental losses
fundamental losses in the motor can be segregated into five different components: iron losses
(varying with motor frequency and applied fundamental voltage), friction and windage losses
(varying with motor speed), rotor winding losses, stator winding losses and additional load
losses (all three varying with motor current). Fundamental losses are the losses of a motor
running with application of rated voltage at fundamental frequency that does not contain any
higher frequencies.
3.5
motor losses with converter supply
if powered by a converter, motor losses are a combination of losses caused by fundamental
frequency and losses caused by the converter high frequencies
3.6
multi-level voltage source converter
frequency converter topology, where the output voltage (phase-to-ground) is switched in three
or more steps or levels up to the maximum possible output value of both positive and negative
voltage
3.7
switching event
operation sequence of one semiconductor with switching once on and switching once off

– 10 – IEC 60034-2-3:2024 © IEC 2024
3.8
switching frequency
number of switching events of one semiconductor within one second. It determines, together
with the selected pulse pattern and the converter topology, the lowest frequency of
non-controllable high frequencies or inter-harmonics at the IPC (in-plant point of coupling) of
the motor
3.9
thermal equilibrium
steady state temperature level of a motor which is reached, if the rate of change of temperature
is 1 K or less per half hour
3.10
two-level voltage source converter
frequency converter topology, where the output voltage (phase-to-ground) is switched between
two levels
Note 1 to entry: For a two-level converter, the pulse frequency measured phase to phase is two times the switching
frequency defined in 3.8 in case of continuous modulation and about 1,33 times the switching frequency defined in
3.8 in case of discontinuous modulation.
4 Symbols and abbreviated terms
c Loss separation coefficient for friction and windage losses and hysteresis losses
BH
c Winding connection coefficient
Con
c Loss separation coefficient for hysteresis losses and eddy current losses
fe
c Loss separation coefficient for additional load losses
LL
c Voltage coefficient
Volt
c Loss separation coefficient for winding losses and high frequency losses
WHf
f Frequency, Hz
f Fundamental motor frequency, Hz
Mot
f Rated motor frequency, Hz
N
f Switching frequency, Hz
sw
No-load current, A
I
I Rated current, A
N
MTPA Maximum torque per ampere
−1
n Speed, s
−1
n Rated speed, s
N
−1
n Reference speed, s
ref
n Relative speed at which field weakening range starts,
FW
P Power, W
P Constant losses if supplied by a converter, W
Ccon
P Constant losses at sinusoidal supply according to IEC 60034-2-1, W
Csin
PDS Power drive system
P Additional high frequency loss due to converter supply, W
LHL
Rated power, W
P
N
IEC 60034-2-3:2024 © IEC 2024 – 11 –
P Reference power, W
ref
P Motor input power if supplied by a converter, W
1C
P Motor input power at sinusoidal supply according to IEC 60034-2-1, W
1_60034-2-1
P Motor output power if supplied by a converter, W
2C
P Motor output power at sinusoidal supply according to IEC 60034-2-1, W
2_60034-2-1
PWM Pulse width modulation
T Motor torque, Nm
T Motor torque if supplied by a converter, Nm
C
Rated torque, Nm
T
N
T Reference torque, Nm
ref
U Rated motor voltage, V
N
η Efficiency
5 Basic requirements
5.1 Instrumentation
5.1.1 General
Unless otherwise stated in this document, the arithmetic average of the three line currents and
voltages shall be used.
If testing electric motors under load, slow fluctuations in the output power and other measured
quantities may be unavoidable. Therefore, for each load point many readings shall be taken
automatically by a suitable digital meter over a period of at least 5 s but not more than 60 s and
this average shall be used for the determination of efficiency.
For winding temperature measurements, the methods described in IEC 60034-2-1 shall be
used. The resistance method is preferred.
5.1.2 Power analyser and transducers
Considering the high frequencies involved in converters feeding AC motors and their
contribution to the motor losses, the measuring equipment shall be selected according to the
range of relevant frequencies with sufficient accuracy.
The instrumentation for measuring power and current at the motor input shall meet the
requirements of IEC 60034-2-1. Due to higher frequency components the following additional
requirements shall also apply.
The specified uncertainty of the power meters shall be 0,2 % of the apparent power at rated
operation of the motor or better for the rated power at 50 Hz or 60 Hz. This is the total
uncertainty of the power meter including possible sensors.
NOTE 1 For example, if a three-phase motor has a rated voltage of 400 V and a rated current of 10 A then the
power meter's active power uncertainty must be 0,2 % or less of √3 times 4 000 VA, which is 13,9 W or better.
The bandwidth of power meters and sensors shall be sufficiently wide so that the error in the
measurement of total calculated active power for the entire frequency range (beyond 50 Hz and
60 Hz) is less than or equal to 0,3 % of the apparent power.
NOTE 2 In general, a bandwidth from 0 Hz up to 10 times of switching frequency is sufficient.

– 12 – IEC 60034-2-3:2024 © IEC 2024
If an external current transducer is required, no conventional current transformers shall be used.
Instead, wide bandwidth shunts or zero-flux transducers shall be used.
Fundamental voltage shall be measured at the motor terminals using a digital power analyser
equipped with suitable software (FFT, Fast Fourier Transformation).
Internal line filters in digital power meters may be used for frequencies 10-times higher than
the switching frequency. Synchronization filters (also known as zero-cross filters) that are not
in the signal path may be used additionally.
For power measurement, the three-wattmeter method is preferred. All cables used to transmit
measurement signals shall be shielded. It must be noted that the cable shield is not routed
through the current transducers.
5.1.3 Mechanical output of the motor
The instrumentation used to measure supply frequency shall have an accuracy of ±0,1 % of full
scale.
-1 -1
The speed measurement should be accurate within 0,1 min for speeds up to 3 600 min , and
0,03 % above.
The instrumentation used to measure the torque shall have a minimum class of 0,2 if the rated
efficiency is below 92 %, 0,1 below 95 % and 0,05 or better for higher efficiencies, when
applying the preferred method as in Table 1. In case of applying method 2-3-B according to
Table 2, the instrumentation shall follow the requirements of IEC 60034-2-1 as minimum. The
minimum torque measured shall be at least 10 % of the torque measurement device’s rated
torque. If a better class instrument is used, the allowed torque range can be extended
accordingly.
5.2 Converter set-up
5.2.1 General
For all tests using the comparable converter, it should be parameterized according to the
requirements of this document or, if a unique combination of converter and motor is to be tested,
the converter should be parameterized according to the specific application requirements. The
chosen parameter settings shall be recorded in the test report.
5.2.2 Comparable converter set-up for rated voltages up to 1 kV
The comparable converter shall be understood as a voltage source independent of load current.
The so-called comparable converter operating mode is not intended or requested for any
commercial application, but it is a typical set-up. The purpose of the comparable converter set-
up is to establish comparable test conditions for motors designed for operation with
commercially available converters.
The reference conditions defined below shall only be used for verification of compliance with
national motor efficiency regulations, in particular the 90 % speed and 100 % torque load point.
For all other purposes including the interpolation procedure, preferably the original system
configuration should be used.
IEC 60034-2-3:2024 © IEC 2024 – 13 –
The following reference conditions are defined:
• The converter shall be a two-level voltage source converter type.
• No additional components influencing output voltage or output current shall be installed
between the comparable converter and the motor, except those required for the measuring
instruments.
• Operation at 90 % speed and rated torque.
• Operation with constant flux (approx. 90 % of rated voltage) for both induction motors and
synchronous motors unless otherwise explicitly defined in the motor documentation.
NOTE The rated flux is defined by the rated voltage given on the name plate of the motor. Rated flux at 90 % speed
results in 90 % rated voltage. Different flux levels may be defined by the motor manufacturer by defining the
preferable motor terminal voltage at 90 % speed explicitly in the motor documentation. Therefore, a measurement at
the 90 % speed and 100 % torque point with preferred flux will be fully replicable for regulation authorities.
-1
• For motors with a rated speed up to 3 600 min , the switching frequency shall not be higher
than 5 kHz.
-1
• For motors with a rated speed above 3 600 min , the switching frequency shall not be higher
than 10 kHz.
The conductor cross-sectional area of the motor cable should be selected such that the voltage
drop is not significant at rated load. An example for a typical test setup can be found in
IEC 61800-9-2.
5.2.3 Converters with rated voltages above 1 kV
For converters with voltage ratings above 1 kV a generally accepted comparable converter and
cable length cannot be specified. Such motors, cables and specific converters can only be
tested as a complete power drive system because the pulse patterns of frequency converters
for higher output powers vary between manufacturers and differ greatly between no-load and
rated load.
5.2.4 Testing with other converters
Motors that are operated with converters that produce a voltage with less harmonic content
than in case of supply by the comparable converter, for example multi-level converters or
converters with higher switching frequencies, will typically have lower losses compared with
measurements made with the comparable converter at 5 kHz or 10 kHz switching frequency.
Reference measurements on such motors shall still be performed under the reference
conditions as given in 5.2.2. Motor efficiency values measured under non-reference conditions
can be provided in the motor documentation.
5.3 Ambient temperature during testing
The ambient temperature should be in the range of 15 °C to 40 °C.
5.4 State of the motor under test
Tests shall be conducted on an assembled motor with the essential components in place, to
obtain test conditions equal or very similar to normal operating conditions. For handling of
sealing systems for efficiency classification related measurements see IEC 60034-30-1 or
IEC TS 60034-30-2.
It is preferable that the motor be selected randomly from series production without special
considerations.
– 14 – IEC 60034-2-3:2024 © IEC 2024
6 Test method for the determination of the efficiency of converter-fed motors
6.1 Selection of determination method
For the verification of the rated losses and energy efficiency according to energy efficiency
classification schemes, the preferred method 2-3-A according to Table 1 shall be applied.
For the efficiency verification by regulators or end-users, the preferred method 2-3-A is
mandatory for verification of rated efficiency declared by the manufacturer. For the declaration
process and the seven load points according to Table 3 or Table 4 the manufacturer is free to
use other applicable determination methods also.
Table 1 – Preferred test methods
Reference Method Description Subclause Required facility
2-3-A Direct-measurement Torque measurement 6.2 Torque measuring device for
Input-output full-load; Comparable or
specific converter supply
Alternate efficiency determining methods according to 2-3-B, 2-3-C and 2-3-D may be used for
any other purpose apart from efficiency verification by regulators, see Table 2.
Table 2 – Other test methods
Reference Method Description Subclause Required facility
2-3-B Summation of losses Additional high
...