IEC 60034-30-3:2024

Rotating electrical machines - Part 30-3: Efficiency classes of high voltage AC motors (IE-code)

IEC 60034-30-3:2024 specifies efficiency classes for fixed-speed three-phase high-voltage cage induction motors in accordance with IEC 60034-1 that
- have a rated voltage exceeding 1 000 V, but not exceeding 11 kV;
- have a rated power from 200 kW to 2 000 kW;
This document provides the global harmonization of energy-efficiency classes of three-phase cage induction motors with rated voltage above 1 000 V that are rated for direct online starting and fixed-speed operation at a 50 Hz or 60 Hz supply with sinusoidal voltage.

Machines électriques tournantes - Partie 30-3: Classes de rendement des moteurs à courant alternatif à haute tension (code IE)

IEC 60034-30-3:2024 spécifie les classes de rendement pour les moteurs triphasés à induction à cage à haute tension et à vitesse fixe conformément à l'IEC 60034-1, qui
- ont une tension assignée supérieure à 1 000 V, mais qui ne dépasse pas 11 kV;
- ont une puissance assignée comprise entre 200 kW et 2 000 kW;
Le présent document prévoit l'harmonisation globale des classes de rendement énergétique des moteurs triphasés à induction à cage dont la tension assignée est supérieure à 1 000 V, qui sont assignés pour démarrer directement sur réseau et fonctionner à vitesse fixe sur une alimentation de 50 Hz ou 60 Hz avec une tension sinusoïdale.

General Information

• Status: Published
• Publication Date: 14-Feb-2024
• ICS: 29.160 - Rotating machinery
• ICS: 29.160.01 - Rotating machinery in general
• ICS: 29.160.10 - Components for rotating machines
• Technical Committee: TC 2 - Rotating machinery
• Drafting Committee: WG 31 - TC 2/WG 31
• Current Stage: PPUB - Publication issued
• Start Date: 15-Feb-2024
• Completion Date: 22-Jan-2024

Standards Content (Sample)

IEC 60034-30-3 ®
Edition 1.0 2024-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Rotating electrical machines –
Part 30-3: Efficiency classes of high voltage AC motors (IE-code)

Machines électriques tournantes –
Partie 30-3: Classes de rendement des moteurs à courant alternatif à haute
tension (code IE)
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IEC 60034-30-3 ®
Edition 1.0 2024-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Rotating electrical machines –

Part 30-3: Efficiency classes of high voltage AC motors (IE-code)

Machines électriques tournantes –

Partie 30-3: Classes de rendement des moteurs à courant alternatif à haute

tension (code IE)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS  29.160.01; 29.160.10; 29.160.30 ISBN 978-2-8322-8126-0

– 2 – IEC 60034-30-3:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 9
3 Terms, definitions and symbols. 9
3.1 Terms and definitions . 9
3.2 Symbols . 10
4 Efficiency classification . 10
4.1 Determination . 10
4.1.1 General . 10
4.1.2 Auxiliary devices . 10
4.2 Efficiency rating – General procedure . 11
5 Required documentation . 18
Annex A (informative) Standardized nameplate efficiency values . 19
Annex B (informative) Proposal for technology factor for starting conditions for high
voltage cage induction motors outside the scope of this document . 20
Annex C (informative) Example for determining the nominal efficiency . 21
Bibliography . 22

Figure 1 – Envelope of the load torque during starting: Load torque during starting in %
of rated torque over speed in % of rated speed . 7

Table 1 – Maximum external moment of inertia . 8
Table 2 – Reference efficiency values η for 2p = 2, f = 50 Hz . 11
r N
Table 3 – Reference efficiency values η for 2p = 4, f = 50 Hz . 12
r N
Table 4 – Reference efficiency values η for 2p = 6, f = 50 Hz . 13
r N
Table 5 – Reference efficiency values η for 2p = 2, f = 60 Hz . 14
r N
Table 6 – Reference efficiency values η for 2p = 4, f = 60 Hz . 15
r N
Table 7 – Reference efficiency values η for 2p = 6, f = 60 Hz . 16
r N
Table 8 – Technology factor c for rated voltage U . 17
u N
Table 9 – Technology factor c for method of cooling (IC class) . 17
c
Table 10 – Technology factor c for starting conditions for motors within the scope of
s
this document . 17
Table A.1 – Standardized nameplate efficiency levels . 19
Table B.1 – Technology factor c for starting conditions for high voltage cage induction
s
motors outside the scope of this document . 20

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –

Part 30-3: Efficiency classes of high voltage AC motors (IE-code)

FOREWORD
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IEC 60034-30-3 has been prepared by IEC technical committee 2: Rotating machinery. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
2/2131/CDV 2/2160/RVC
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.

– 4 – IEC 60034-30-3:2024 © IEC 2024
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.

INTRODUCTION
This document provides the global harmonization of energy-efficiency classes of three-phase
cage induction motors with rated voltage above 1 000 V that are rated for direct online starting
and fixed-speed operation at a 50 Hz or 60 Hz supply with sinusoidal voltage.
For these motors, the demands of the power supply and of the driven equipment in many cases
govern the design of the electrical machine. Due to the large size and power of high-voltage
(HV) motors, these demands are more complex than for low-voltage motors and often limit the
design. Vice versa, the properties of the electrical machine itself influence the grid considerably
in many cases.
In order to ensure an easy applicability of this document, the scope is limited to the most
relevant applications, i.e. motors for driving the vast majority of pumps, fans, or compressors,
which cover approximately 80 % to 90 % of all applications. Motors for special applications, e.g.
for accelerating very high load inertia, for very low supply voltage during starting, for very low
locked-rotor current or for accelerating against high load torque, are therefore out of the scope
of this document.
Despite this, the motor technology, namely
• rated voltage,
• method of cooling,
• locked-rotor current,
have a significant influence on the achievable motor efficiency as well as the rated frequency,
the rated power and the number of poles, and are considered when specifying the efficiency
class.
NOTE When specifying or designing a power drive system, low voltage motors will mostly have a higher efficiency
than high voltage motors with the same rated power. However, considering the losses of the complete system, i.e.
including cabling and transformer losses, high voltage solution might be advantageous.

– 6 – IEC 60034-30-3:2024 © IEC 2024
ROTATING ELECTRICAL MACHINES –

Part 30-3: Efficiency classes of high voltage AC motors (IE-code)

1 Scope
This part of IEC 60034 specifies efficiency classes for fixed-speed three-phase high-voltage
cage induction motors in accordance with IEC 60034-1 that
• have a rated voltage exceeding 1 000 V, but not exceeding 11 kV;
• have a rated power from 200 kW to 2 000 kW;
NOTE 1 Motors with rated power above 2 000 kW are produced in such small numbers and are designed and
produced with a focus on achieving an optimum efficiency anyway, even though fulfilling increasingly special
requirements that assigning efficiency classes would be an additional effort without the result of any countable
energy saving.
• have two, four or six poles;
• are rated for single-speed line-operation;
• are intended for direct-on-line starting at rated or at reduced voltage and rated frequency;
• are constructed to any degree of protection;
• are designed for cooling methods IC411, IC511, IC611, IC01 or IC81W;
• are capable of continuous operation at their rated operating point (torque/power, speed)
with a temperature rise within the specified insulation temperature class;
NOTE 2 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.
• are rated for any ambient temperature or coolant temperature within the range of – 20 °C to
+ 60 °C;
NOTE 3 Motors rated for temperatures outside the range – 20 °C and + 60 °C are considered to be of special
construction and are consequently excluded from this document.
• are rated for an operating altitude up to 2 000 m above sea level;
NOTE 4 The rated efficiency and the efficiency class are based on a rating for altitudes up to 1 000 m above
sea level.
• have a locked-rotor current I at stand-still and supply with rated voltage and frequency
l
before application of any IEC or agreed tolerance in the range I / I ≥ 4,5;
l N
• are designed for a customer load torque during starting not exceeding an envelope with a
minimum of 25 % of the rated torque at low speed and a square shape T ~ n up to a
maximum load torque at full speed of 60 % of the rated torque in case of 2 pole motors or
100 % of the rated torque in case of 4 pole or 6 pole motors, respectively, (see Figure 1),
After starting is completed, the load torque of 2 pole motors is increased to 100 % of the
rated torque;
• have to accelerate an external moment of inertia as defined by the customer requirements
not exceeding the values given in Table 1 considering all start up conditions defined in this
document for not more than three consecutive starts from cold condition or two starts from
hot condition, respectively;
• are designed for a minimum locked-rotor steady state supply voltage of at least 80 % of the
rated voltage during starting.

Figure 1 – Envelope of the load torque during starting:
Load torque during starting in % of rated torque over speed in % of rated speed

– 8 – IEC 60034-30-3:2024 © IEC 2024
Table 1 – Maximum external moment of inertia
Number of poles 2 4 6
Frequency   Hz 50 60 50 60 50 60
Rated output Moment of inertia J
kW
kg m
200 25 15 115 75 310 200
220 25 15 120 80 330 210
250 25 15 130 85 360 230
280 30 20 140 90 400 250
315 30 20 150 100 440 270
355 35 20 170 110 480 300
400 35 25 190 120 530 330
450 40 25 210 130 580 360
500 45 30 230 140 640 400
560 50 30 250 150 700 440
630 55 35 280 170 780 490
710 60 35 310 190 870 550
800 65 40 340 210 970 610
900 70 45 380 230 1 100 680
1 000 80 50 420 260 1 200 750
1 120 90 55 460 290 1 300 830
1 250 100 60 510 320 1 450 920
1 400 110 65 570 360 1 650 1 000
1 600 120 70 640 400 1 850 1 150
1 800 130 80 720 440 2 050 1 300
2 000 150 90 800 490 2 300 1 450
NOTE 1 The values of the moment of inertia given are in terms of mr where m is the mass and r is the mean
radius of gyration.
NOTE 2 Moment of inertia is defined in ISO 3: 1973, 3.7.
NOTE 3 If necessary, linear interpolation is permitted between two adjacent values.

Excluded are:
• Motors with mechanical commutators or slip-rings;
• Motors with 8 or more poles;
• Multi-speed motors;
• Motors with customer starting torque requirements exceeding the load torque envelope
above, and motors exceeding the maximum external inertia defined in Table 1;
• Motors designed specifically for operation fed by a power electronic frequency converter
with a temperature rise within the specified insulation thermal class or thermal class;
• Motors completely integrated with the driven machine (for example pumps, fans and
compressors). This means that the motor cannot be designed in such a way as to enable
the motor to be separated from the driven unit, i.e. it is not possible to operate the separated
motor without the driven unit;
• Submersible motors specifically designed to operate wholly immersed in a liquid;

• Smoke extraction motors;
• Motors dedicated to operate in explosive atmospheres;
• Motors for operation in nuclear plants, especially nuclear power plants.
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 60034-1:2022, 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 60050-411:1996, International Electrotechnical Vocabulary (IEV) – Part 411: Rotating
machinery
IEC 60050-411:1996/AMD1:2007
IEC 60050-411:1996/AMD2:2021
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions in IEC 60050-411, IEC 60034-1,
and the following apply.
NOTE 1 For definitions concerning cooling and coolants, other than those in 3.17 to 3.22, see IEC 60034-6.
NOTE 2 For the purposes of this document, the term ‘agreement’ means ‘agreement between the manufacturer and
purchaser’.
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 Terms and definitions
3.1.1
reference efficiency
efficiency value required to meet a certain efficiency class according to the efficiency tables in
this document before technology factors for voltage, cooling or starting conditions are applied
3.1.2
nominal efficiency
efficiency value that a motor’s assigned rated efficiency must meet or exceed at rated operation
for a certain efficiency class, considering starting requirements and motor technology
3.1.3
rated efficiency
efficiency value assigned by the manufacturer to the motor for operation at rated conditions
before the application of any IEC or agreed tolerance

– 10 – IEC 60034-30-3:2024 © IEC 2024
3.1.4
average motor torque
mean value of the steady-state torque at the motor shaft between stand-still and no-load
operation when supplied with rated voltage and frequency
3.1.5
load torque
speed-dependent torque requirement of the driven equipment at the motor shaft during start-up
of the motor between stand-still and full speed
3.2 Symbols
is the locked-rotor current at rated voltage before application of any IEC or agreed
I
l
tolerance
I is the rated current
N
T is the average motor torque as defined in 3.1.4
av
T is the rated torque
N
P is the rated power
N
2p is the number of poles
U is the rated voltage
N
η is the nominal efficiency
n
η is the reference efficiency
r
η is the rated efficiency
N
4 Efficiency classification
4.1 Determination
4.1.1 General
For assigning an efficiency class, efficiency and losses of AC motors within the scope shall be
tested according to IEC 60034-2-1 using method 2-1-1B or method 2-1-1C from this document.
4.1.2 Auxiliary devices
Some electric motors covered by this document may be equipped with auxiliary devices such
as shaft seals, mechanical brakes, back-stops and unidirectional bearings, speed sensors,
tacho-generators in various combinations.
However, as long as 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.
Angular-contact bearings (thrust bearings) for vertical mounted motors may be replaced by
standard bearings during efficiency testing. All vertical motors may be tested horizontally.
Some types of motors (like pump motors and others) are equipped with shaft seals to prevent
ingress of oil or water into the motor. External seals may 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 the 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.
4.2 Efficiency rating – General procedure
A motor’s rated efficiency η is determined from the losses at rated operation obtained by
N
measurement according to IEC 60034-2-1.
The reference efficiency η (i.e. not considering starting conditions and motor technology) for a
r
, the number of poles 2p and the rated frequency
certain IE class depends on the rated power P
N
f . It is given in Table 2 to Table 7.
N
IE4 levels of efficiency are added for future consideration and might be unachievable for some
power ratings.
Table 2 – Reference efficiency values η for 2p = 2, f = 50 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 2
P in kW
N
200 90,65 % 91,79 % 92,79 % 93,67 %
220 90,91 % 92,03 % 93,00 % 93,86 %
250 91,18 % 92,27 % 93,22 % 94,06 %
280 91,46 % 92,52 % 93,44 % 94,26 %
315 91,79 % 92,81 % 93,70 % 94,49 %
355 92,12 % 93,11 % 93,97 % 94,73 %
400 92,39 % 93,36 % 94,20 % 94,93 %
450 92,67 % 93,60 % 94,42 % 95,13 %
500 92,94 % 93,85 % 94,64 % 95,32 %
560 93,22 % 94,09 % 94,86 % 95,52 %
630 93,49 % 94,34 % 95,08 % 95,72 %
710 93,71 % 94,53 % 95,25 % 95,88 %
800 93,92 % 94,73 % 95,43 % 96,04 %
900 94,08 % 94,87 % 95,56 % 96,16 %
1 000 94,23 % 95,00 % 95,68 % 96,26 %
1 120 94,41 % 95,17 % 95,83 % 96,40 %
1 250 94,59 % 95,33 % 95,97 % 96,53 %
1 400 94,76 % 95,48 % 96,11 % 96,65 %
1 600 94,95 % 95,64 % 96,25 % 96,78 %
1 800 95,08 % 95,77 % 96,36 % 96,88 %
2 000 95,22 % 95,89 % 96,47 % 96,98 %

– 12 – IEC 60034-30-3:2024 © IEC 2024
Table 3 – Reference efficiency values η for 2p = 4, f = 50 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 4
P in kW
N
200 90,88 % 92,00 % 92,97 % 93,83 %
220 91,14 % 92,23 % 93,18 % 94,02 %
250 91,41 % 92,47 % 93,39 % 94,21 %
280 91,68 % 92,71 % 93,61 % 94,40 %
315 92,00 % 93,00 % 93,87 % 94,63 %
355 92,32 % 93,29 % 94,13 % 94,87 %
400 92,59 % 93,53 % 94,35 % 95,06 %
450 92,86 % 93,77 % 94,57 % 95,26 %
500 93,13 % 94,01 % 94,77 % 95,44 %
560 93,40 % 94,25 % 94,99 % 95,64 %
630 93,67 % 94,49 % 95,21 % 95,84 %
710 93,88 % 94,68 % 95,38 % 95,99 %
800 94,09 % 94,87 % 95,55 % 96,15 %
900 94,24 % 95,01 % 95,68 % 96,26 %
1 000 94,39 % 95,14 % 95,80 % 96,37 %
1 120 94,57 % 95,31 % 95,95 % 96,51 %
1 250 94,74 % 95,46 % 96,08 % 96,63 %
1 400 94,91 % 95,61 % 96,22 % 96,75 %
1 600 95,09 % 95,77 % 96,36 % 96,88 %
1 800 95,22 % 95,89 % 96,47 % 96,98 %
2 000 95,36 % 96,01 % 96,58 % 97,07 %

Table 4 – Reference efficiency values η for 2p = 6, f = 50 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 6
P in kW
N
200 90,57 % 91,72 % 92,73 % 93,62 %
220 90,83 % 91,96 % 92,94 % 93,81 %
250 91,11 % 92,21 % 93,16 % 94,01 %
280 91,38 % 92,45 % 93,38 % 94,21 %
315 91,72 % 92,75 % 93,65 % 94,45 %
355 92,05 % 93,05 % 93,92 % 94,68 %
400 92,33 % 93,30 % 94,15 % 94,88 %
450 92,60 % 93,54 % 94,37 % 95,09 %
500 92,88 % 93,79 % 94,59 % 95,28 %
560 93,16 % 94,04 % 94,81 % 95,48 %
630 93,43 % 94,29 % 95,03 % 95,68 %
710 93,65 % 94,48 % 95,21 % 95,84 %
800 93,87 % 94,68 % 95,38 % 96,00 %
900 94,03 % 94,82 % 95,51 % 96,12 %
1 000 94,17 % 94,95 % 95,63 % 96,23 %
1 120 94,36 % 95,13 % 95,79 % 96,37 %
1 250 94,54 % 95,28 % 95,93 % 96,49 %
1 400 94,70 % 95,44 % 96,07 % 96,62 %
1 600 94,90 % 95,60 % 96,22 % 96,75 %
1 800 95,04 % 95,73 % 96,33 % 96,85 %
2 000 95,18 % 95,85 % 96,44 % 96,95 %

– 14 – IEC 60034-30-3:2024 © IEC 2024
Table 5 – Reference efficiency values η for 2p = 2, f = 60 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 2
P in kW
N
200 90,73 % 91,90 % 92,93 % 93,83 %
220 90,96 % 92,10 % 93,11 % 93,99 %
250 91,18 % 92,30 % 93,28 % 94,14 %
280 91,41 % 92,50 % 93,46 % 94,30 %
315 91,64 % 92,70 % 93,63 % 94,45 %
355 91,98 % 93,00 % 93,90 % 94,68 %
400 92,32 % 93,30 % 94,16 % 94,91 %
450 92,61 % 93,55 % 94,38 % 95,10 %
500 92,89 % 93,80 % 94,60 % 95,29 %
560 93,18 % 94,05 % 94,81 % 95,48 %
630 93,40 % 94,25 % 94,99 % 95,64 %
710 93,63 % 94,45 % 95,16 % 95,79 %
800 93,80 % 94,60 % 95,30 % 95,90 %
900 93,92 % 94,70 % 95,38 % 95,98 %
1 000 93,98 % 94,75 % 95,43 % 96,02 %
1 120 94,01 % 94,78 % 95,45 % 96,04 %
1 250 94,04 % 94,81 % 95,48 % 96,06 %
1 400 94,08 % 94,84 % 95,50 % 96,08 %
1 600 94,10 % 94,86 % 95,52 % 96,10 %
1 800 94,12 % 94,88 % 95,54 % 96,11 %
2 000 94,15 % 94,90 % 95,56 % 96,13 %

Table 6 – Reference efficiency values η for 2p = 4, f = 60 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 4
P in kW
N
200 91,52 % 92,60 % 93,54 % 94,37 %
220 91,64 % 92,70 % 93,63 % 94,45 %
250 91,75 % 92,80 % 93,72 % 94,53 %
280 91,87 % 92,90 % 93,81 % 94,60 %
315 92,04 % 93,05 % 93,94 % 94,72 %
355 92,21 % 93,20 % 94,07 % 94,83 %
400 92,38 % 93,35 % 94,20 % 94,95 %
450 92,55 % 93,50 % 94,33 % 95,06 %
500 92,72 % 93,65 % 94,47 % 95,18 %
560 92,95 % 93,85 % 94,64 % 95,33 %
630 93,12 % 94,00 % 94,77 % 95,44 %
710 93,23 % 94,10 % 94,86 % 95,52 %
800 93,35 % 94,20 % 94,95 % 95,60 %
900 93,40 % 94,25 % 94,99 % 95,64 %
1 000 93,44 % 94,28 % 95,02 % 95,66 %
1 120 93,46 % 94,30 % 95,03 % 95,67 %
1 250 93,48 % 94,32 % 95,05 % 95,69 %
1 400 93,51 % 94,34 % 95,07 % 95,70 %
1 600 93,53 % 94,36 % 95,09 % 95,72 %
1 800 93,55 % 94,38 % 95,10 % 95,73 %
2 000 93,58 % 94,40 % 95,12 % 95,75 %

– 16 – IEC 60034-30-3:2024 © IEC 2024
Table 7 – Reference efficiency values η for 2p = 6, f = 60 Hz
r N
IE-class
IE1 IE2 IE3 IE4
2p = 6
P in kW
N
200 91,30 % 92,40 % 93,37 % 94,22 %
220 91,41 % 92,50 % 93,46 % 94,30 %
250 91,53 % 92,61 % 93,55 % 94,38 %
280 91,65 % 92,71 % 93,64 % 94,46 %
315 91,82 % 92,86 % 93,77 % 94,57 %
355 92,00 % 93,02 % 93,91 % 94,69 %
400 92,17 % 93,17 % 94,04 % 94,81 %
450 92,35 % 93,32 % 94,18 % 94,93 %
500 92,52 % 93,48 % 94,31 % 95,05 %
560 92,76 % 93,68 % 94,49 % 95,20 %
630 92,93 % 93,84 % 94,63 % 95,32 %
710 93,05 % 93,94 % 94,72 % 95,40 %
800 93,17 % 94,04 % 94,81 % 95,48 %
900 93,22 % 94,09 % 94,85 % 95,52 %
1 000 93,26 % 94,12 % 94,88 % 95,54 %
1 120 93,28 % 94,14 % 94,90 % 95,55 %
1 250 93,31 % 94,16 % 94,92 % 95,57 %
1 400 93,33 % 94,19 % 94,93 % 95,59 %
1 600 93,35 % 94,21 % 94,95 % 95,60 %
1 800 93,38 % 94,23 % 94,97 % 95,62 %
2 000 93,40 % 94,25 % 94,99 % 95,63 %

In case the rated power of a motor does not meet one of the values in these tables, the reference
efficiency shall be determined as follows:
• The reference efficiency of a rated power at or above the midpoint between two consecutive
power values from the tables shall be the higher of the two efficiencies.
• The reference efficiency of a rated power below the midpoint between two consecutive
power values from the tables shall be the lower of the two efficiencies.

The nominal efficiency η , which a motor’s rated efficiency shall achieve or exceed in order to
n
assign a certain IE class, considers the motor technology, i. e. the motor’s rated voltage, the
method of cooling, and the starting conditions. It is calculated by
c ⋅c
uc
η =
n
 
1+⋅c –1
 
s
η
 r 
where
c is the technology factor for rated voltage, to be taken from Table 8,
u
c is the technology factor for method of cooling, to be taken from Table 9,
c
is the technology factor for starting conditions, to be taken from Table 10.
c
s
The nominal efficiency shall be rounded to three digits, e.g. 0,953 or 95,3 %.
NOTE 1 For information about standardized nameplate efficiency values in some countries, see Annex A.
NOTE 2 For an application example, see Annex C.
Variations in materials, manufacturing processes and in testing result in motor-to-motor
efficiency variations for a given motor design. Therefore, the test efficiency of any individual
motor shall not be less than the assigned rated efficiency minus the tolerance in accordance
with Clause 12 of IEC 60034-1:2022. This statement does not imply that every individual motor
has to be tested.
Table 8 – Technology factor c for rated voltage U
u N
U < 3,0 kV 3,0 kV ≤ U 5,0 kV ≤ U 7,0 kV ≤ U 10,5 kV ≤ U
N N N N N
< 5,0 kV < 7,0 kV < 10,5 kV ≤ 11,0 kV
c 1,003 1,000 0,995 0,992 0,985
u
Table 9 – Technology factor c for method of cooling (IC class)
c
IC01, IC81W IC411 IC511, IC611
c 0,996 1,000 0,990
c
Table 10 – Technology factor c for starting conditions for motors
s
within the scope of this document
I / I c
l N s
4,5 ≤ I / I ≤ 5,0
1,10
l N
5,0 < I / I ≤ 5,5
1,05
l N
5,5 < I / I ≤ 6,5 1,00
l N
6,5 < I / I
0,95
l N
– 18 – IEC 60034-30-3:2024 © IEC 2024
The technology factor for starting conditions c considers that, for motors within the scope of
s
this standard, the main restriction for DOL starting that is related to the grid is the locked-rotor
current I . The locked-rotor current is defined as the motor’s current at stand-still and supply
l
with rated voltage and frequency as assigned by the manufacturer in the data sheet before
application of any IEC or agreed tolerance.
NOTE 3 Annex B proposes Table B.1 for determining the technology factor for starting conditions for motors outside
the scope of this document for future consideration.
5 Required documentation
The IE code of the efficiency class and the rated efficiency shall be durably marked on the
rating plate, e.g. IE2 95,4 %, as well as the rated voltage, the method of cooling, and the locked-
rotor current or the locked-rotor apparent power.
Some motors have rated efficiencies below IE1. No marking of these motors shall be required.
The motor documentation should contain the steady-state torque-speed and current-speed
curves of the motor as calculated by the manufacturer.

Annex A
(informative)
Standardized nameplate efficiency values
For motors designed per NEMA MG 1, only the efficiency values in Table A.1 are allowed to
appear on the rating plate, based on regulations by the US Department of Energy. The purpose
of Table A.1 is to limit the number of efficiency steps that can be documented on the nameplate
in order to ensure that there is a significant measurable difference between various efficiency
claims. Thus, claims are significant with regard to testing accuracy and manufacturing variation.
Table A.1 – Standardized nameplate efficiency levels
99,0 98,4 97,1 95,0 91,7
98,9 98,2 96,8 94,5 91,0
98,8 98,0 96,5 94,1 90,2
98,7 97,8 96,2 93,6 89,5
98,6 97,6 95,8 93,0
98,5 97,4 95,4 92,4
– 20 – IEC 60034-30-3:2024 © IEC 2024
Annex B
(informative)
Proposal for technology factor for starting conditions for high voltage
cage induction motors outside the scope of this document
The main idea of the proposal in this annex is using, besides the locked-rotor current, only the
average value of the motor torque between stand-still and no-load operation at rated voltage
as criterion for considering the influence of different starting conditions such load inertia, load
torque curve or minimum supply voltage during starting, thus allowing to compare the nominal
efficiency of motors for different starting conditions.
For high voltage cage induction motors outside the scope of this document, it is proposed to
take the technology factor for starting conditions from Table B.1.
for starting conditions for high voltage cage induction
Table B.1 – Technology factor c
s
motors outside the scope of this document
T / T
av N
T / T ≤ 0,7 0,7 < T / T ≤ 1,0 1,0 < T / T ≤ 1,3 1,3 < T / T
av N av N av N av N
I / I
l N
I / I ≤ 3,5
1,15 1,15 1,15 1,15
l N
3,5 < I / I ≤ 4,0 1,10 1,15 1,15 1,15
l N
4,0 < I / I ≤ 4,5
1,05 1,10 1,15 1,15
l N
4,5 < I / I ≤ 5,0
1,00 1,05 1,10 1,15
l N
5,0 < I / I ≤ 5,5
0,95 1,00 1,05 1,10
l N
5,5 < I / I ≤ 6,0
0,90 0,95 1,00 1,05
l N
6,0 < I / I ≤ 6,5
0,85 0,90 0,95 1,00
l N
6,5 < I / I ≤ 7,0
0,80 0,85 0,90 0,95
l N
7,0 < I / I
0,75 0,80 0,85 0,90
l N
The technology factor for starting conditions c considers that, in case of high voltage cage
s
induction motors outside the scope of this document, the main restrictions for DOL starting are
– the locked-rotor current I at rated voltage, and
l
– the minimum supply voltage during starting, the external inertia, and the load torque and its
dependency on the speed, which define the required torque speed curve of the motor and
thus the average motor torque T as defined in 3.1.4.
av
The locked-rotor current is defined as current at stand-still and supply with rated voltage and
frequency before application of any IEC or agreed tolerance.
The average motor torque is calculated from the torque-speed curve as provided by the motor
manufacturer and supplied with the documentation. The characteristic points of the provided
torque-speed curve, i.e. locked-rotor torque, pull-up torque, and breakdown torque, are subject
to the tolerances as defined in Clause 12 of IEC 60034-1:2022. A validation of this curve by
measurement is not required.
Annex C
(informative)
Example for determining the nominal efficiency
In case of an example motor with
• number of poles: 4
• rated power: 850 kW
• rated voltage: 6 000 V
• rated frequency: 50 Hz
• locked-rotor current: 6,7 × rated current
• method of cooling: IC 81W,
the nominal efficiency values for the different IE classes are determined in the following steps:
a) Reference efficiency values to be taken from the 900 kW line of Table 3 (4 poles, 50 Hz),
i.e. 94,24 % for IE1, 95,01 % for IE2, 95,68 % for IE3, and 96,26 % for IE4.
b) Technology factor for rated voltage to be taken from Table 8, i.e. c = 0,995.
u
c) Technology factor for method of cooling to be taken from Table 9, i.e. c = 0,996.
c
d) Technology factor for starting conditions to be taken from Table 10, i.e. c = 0,95.
s
e) Nominal efficiency values to be calculated using the core formula, i.e. in case of IE3:
0,995⋅0,996
η 0,9503 95,0%
n
 1 
1+⋅0,95 –1
 
0,9568
 
== =
– 22 – IEC 60034-30-3:2024 © IEC 2024
Bibliography
IEC 60034-5, Rotating electrical machines – Part 5: Degrees of protection provided by the
integral design of rotating electrical machines (IP code) – Classification
IEC 60034-6, Rotating electrical machines – Part 6: Methods of cooling (IC Code)
IEC TS 60034-31, Rotating electrical machines – Part 31: Selection of energy-efficient motors
including variable speed applications – Application guide
ISO 3:1973, Preferred numbers – Series of preferred numbers
EN 12101-3, Smoke and heat control systems – Part 3: Specification for powered smoke and
heat exhaust ventilators
____________
– 24 – IEC 60034-30-3:2024 © IEC 2024
SOMMAIRE
AVANT-PROPOS . 25
INTRODUCTION . 27
1 Domaine d'application . 28
2 Références normatives . 31
3 Termes, définitions et symboles . 31
3.1 Termes et définitions . 31
3.2 Symboles . 32
4 Classification du rendement. 32
4.1 Détermination . 32
4.1.1 Généralités . 32
4.1.2 Dispositifs auxiliaires . 32
4.2 Caractéristiques assignées de rendement – Procédure générale . 33
5 Documentation exigée . 41
Annexe A (informative) Valeurs de rendement nominal normalisées . 42
Annexe B (informative) Proposition concernant le facteur de technologie pour les
conditions de démarrage des moteurs à induction à cage à h
...