Rotating electrical machines - Part 9: Noise limits

Specifies test methods for the determination of sound power level of rotating electrical machines. Provides maximum A-weighted sound power levels for factory acceptance testing of rotating electrical machines. To be used in conjunction with IEC 60034-1, IEC 60034-5 and IEC 60034-6. This consolidated version consists of the fourth edition (2003), and its amendment 1 (2007). Therefore, no need to order amendment in addition to this publication.

Machines électriques tournantes - Partie 9: Limites de bruit

Spécifie les méthodes d'essai pour la détermination du niveau de puissance acoustique des machines électriques tournantes. Fournit les niveaux maximaux de puissance acoustique pondérée A pour les essais de réception en usine des machines électriques tournantes. A utiliser conjointement avec les CEI 60034-1, CEI 60034-5 et CEI 60034-6.  Cette version consolidée comprend la quatrième édition (2003), et son amendement 1 (2007). Il n'est donc pas nécessaire de commander l'amendement avec cette publication.

General Information

Status
Published
Publication Date
24-Jul-2007
Technical Committee
Current Stage
DELPUB - Deleted Publication
Completion Date
14-Oct-2021
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IEC 60034-9
®

Edition 4.1 2007-07
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE


Rotating electrical machines –
Part 9: Noise limits

Machines électriques tournantes –
Partie 9: Limites de bruit

IEC 60034-9:2003+A1:2007

---------------------- Page: 1 ----------------------
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IEC 60034-9

®


Edition 4.1 2007-07




CONSOLIDATED



VERSION




VERSION



CONSOLIDÉE











Rotating electrical machines –

Part 9: Noise limits




Machines électriques tournantes –

Partie 9: Limites de bruit
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

INTERNATIONALE



ICS 29.160 ISBN 2-8318-9087-X




® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – 60034-9  IEC:2003+A1:2007

CONTENTS
FOREWORD . 3
INTRODUCTION . 5

1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Methods of measurement . 8
5 Test conditions . 8
5.1 Machine mounting . 8
5.1.1 Precautions . 8
5.1.2 Resilient mounting . 8
5.1.3 Rigid mounting . 9
5.2 Test operating conditions . 9
6 Sound power level limits . 9
7 Determination of noise increments caused by converter supply . 10
8 Determination of sound pressure level . 12
9 Declaration and verification of sound power values . 13

Table 1 – Maximum A-weighted sound power level, L in dB, at no-load
WA
(excluding motors according to Table 2) . 14

Table 2 – Maximum A-weighted sound power level, L in dB, at no-load
WA
(for single speed three-phase cage induction motors IC411, IC511, IC611) . 15
Table 3 – Maximum expected increase, over no-load condition, in A-weighted sound
power levels, ΔL in dB, for rated load condition (for motors according to table 2) . 16
WA

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60034-9  IEC:2003+A1:2007 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ROTATING ELECTRICAL MACHINES –

Part 9: Noise limits



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, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60034-9 has been prepared by IEC technical committee 2:
Rotating machinery.
This edition includes the following significant technical changes:
• this edition reduces the no-load noise limits for single-speed, cage-induction motors
according to Table 2;
• it also provides informative guidance on
– the measurement surface to be used during some tests,
– a method for the determination of an average sound pressure level,
– an indication of “uncertainty” based upon the category of test procedure.

---------------------- Page: 5 ----------------------
– 4 – 60034-9  IEC:2003+A1:2007
This consolidated version of IEC 60034-9 consists of the fourth edition (2003) [documents
2/1256/FDIS and 2/1272/RVD] and its amendment 1 (2007) [documents 2/1383/CDV and
2/1413/RVC].
The technical content is therefore identical to the base edition and its amendment(s) and has
been prepared for user convenience.
It bears the edition number 4.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date,
the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

---------------------- Page: 6 ----------------------
60034-9  IEC:2003+A1:2007 – 5 –
INTRODUCTION
Acoustic quantities can be expressed in sound pressure terms or sound power terms. The use
of a sound power level, which can be specified independently of the measurement surface
and environmental conditions, avoids the complications associated with sound pressure
levels, which require additional data to be specified. Sound power levels provide a measure of
radiated energy and have advantages in acoustic analysis and design.

---------------------- Page: 7 ----------------------
– 6 – 60034-9  IEC:2003+A1:2007
ROTATING ELECTRICAL MACHINES –

Part 9: Noise limits



1 Scope
This part of IEC 60034:
– specifies test methods for the determination of sound power level of rotating electrical
machines;
– specifies maximum A-weighted sound power levels for factory acceptance testing of
network-supplied, rotating electrical machines in accordance with lEC 60034-1, having
methods of cooling according to lEC 60034-6 and degrees of protection according to
lEC 60034-5, and having the following characteristics:
• standard design, either a.c. or d.c., without additional special electrical, mechanical, or
acoustical modifications intended to reduce the sound power level;
• rated output from 1 kW (or kVA) up to and including 5 500 kW (or kVA);
–1
• rated speed not greater than 3 750 min .
– provides guidance for the determination of noise levels for a.c. cage induction motors
supplied by converters.
Excluded are a.c. motors supplied by converters. For these conditions see IEC 60034-17
for guidance.
The object of this standard is to determine maximum A-weighted sound power levels, L in
WA
decibels, dB, for airborne noise emitted by rotating electrical machines of standard design, as
a function of power, speed and load, and to specify the method of measurement and the test
conditions appropriate for the determination of the sound power level of the machines to
provide a standardized evaluation of machine noise up to the maximum specified sound
power levels. This standard does not provide correction for the existence of tonal
characteristics.
Sound pressure levels at a distance from the machine may be required in some applications,
such as hearing protection programs. Information is provided on such a procedure in Clause 8
based on a standardized test environment.
NOTE 1 This standard recognizes the economic reason for the availability of standard noise-level machines for
use in non-critical areas or for use with supplementary means of noise attenuation.
NOTE 2 Where sound power levels lower than those specified in Tables 1 or 2 are required, these should be
agreed between the manufacturer and the purchaser, as special electrical, mechanical, or acoustical design may
involve additional measures.
2 Normative references
The following referenced documents are indispensable for the application 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

---------------------- Page: 8 ----------------------
60034-9  IEC:2003+A1:2007 – 7 –
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 60034-17, Rotating electrical machines – Part 17: Cage induction motors when fed from
convertors – Application guide
ISO 3741, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Precision methods for reverberation rooms
ISO 3743-1, Acoustics – Determination of sound power levels of noise sources – Engineering
methods for small, movable sources in reverberant fields – Part 1: Comparison method for
hard-walled test rooms
ISO 3743-2, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Engineering methods for small, movable sources in reverberant fields – Part 2:
Method for special reverberation test rooms
ISO 3744: Acoustics – Determination of sound power levels of noise sources using sound
pressure – Engineering method in an essentially free field over a reflecting plane
ISO 3745, Acoustics – Determination of sound power levels of noise sources – Precision
methods for anechoic and semi-anechoic rooms
ISO 3746, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Survey method using an enveloping measurement surface over a reflecting plane
ISO 3747, Acoustics – Determination of sound power levels of noise sources using sound
pressure – Comparison method in situ
ISO 4871, Acoustics – Declaration and verification of noise emission values of machinery and
equipment
ISO 9614-1, Acoustics – Determination of sound power levels of noise sources using sound
intensity – Part 1: Measurement at discrete points
ISO 9614-2, Acoustics – Determination of sound power levels of noise sources using sound
intensity – Part 2: Measurement by scanning
3 Terms and definitions
For the purposes of this document, the terms and definitions given in the standards listed in
the normative references together with the following apply.
3.1
sound power level
L
W
ten times the logarithm to the base 10 of the ratio of the sound power radiated by the source
–12
under test to the reference sound power [W = 1 pW (10 W)] expressed in decibels
o
3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure to the
–5
square of the reference sound pressure [P = 20 µPa (2 × 10 Pa)] expressed in decibels
o

---------------------- Page: 9 ----------------------
– 8 – 60034-9  IEC:2003+A1:2007
4 Methods of measurement
4.1 Sound pressure level measurements and calculation of sound power level produced by
the machine shall be made in accordance with ISO 3744, unless one of the alternative
methods specified in 4.3 or 4.4 below applies.
NOTE It is recommended that the hemispherical method be used for machines with shaft height up to 180 mm
and the parallelepiped method used for machines larger than 355 mm. Either method may be used for intermediate
shaft heights.
4.2 The maximum sound power levels specified in Tables 1 and 2 or adjusted by Table 3,
relate to measurements made in accordance with 4.1.
4.3 When appropriate, one of the methods of precision or engineering grade accuracy, such
as the methods of ISO 3741, ISO 3743-1, ISO 3743-2, ISO 3745, ISO 9614-1 or ISO 9614-2,
may be used to determine sound power levels.
4.4 The simpler but less accurate method specified in ISO 3746 or ISO 3747 may be used,
especially when the environmental conditions required by ISO 3744 cannot be satisfied (for
example, for large machines).
However, to prove compliance with this standard, unless a correction due to inaccuracy of the
measurement has already been applied to the values determined by this method in
accordance with ISO 3746 or ISO 3747, the levels of Tables 1 and 2 shall be decreased by
2 dB.
4.5 If testing under rated load conditions, the methods of ISO 9614 are preferred. However,
other methods are allowed when the load machine and auxiliary equipment are acoustically
isolated or located outside the test environment.
5 Test conditions
5.1 Machine mounting
5.1.1 Precautions
Care should be taken to minimize the transmission and the radiation of structure-borne noise
from all mounting elements including the foundation. This can be achieved by the resilient
mounting for smaller machines, however, larger machines can usually only be tested under
rigid mounting conditions.
Machines tested under load conditions shall be rigidly mounted.
5.1.2 Resilient mounting
The natural frequency of the support system and the machine under test shall be lower than
a quarter of the frequency corresponding to the lowest rotational speed of the machine.
The effective mass of the resilient support shall be not greater than one-tenth of that of the
machine under test.

---------------------- Page: 10 ----------------------
60034-9  IEC:2003+A1:2007 – 9 –
5.1.3 Rigid mounting
The machines shall be rigidly mounted to a surface with dimensions adequate for the machine
type (for example by foot or flange fixed in accordance with the manufacturer's instructions).
The machine shall not be subject to additional mounting stresses from incorrect shimming or
fasteners.
5.2 Test operating conditions
The following test conditions shall apply:
a) The machine shall operate at rated voltage(s), rated frequency or rated speed(s) and with
appropriate field current(s) (when applicable). These shall be measured with instruments
of an accuracy of 1 % or better.
1) The standard load condition shall be no-load, except for series wound motors.
2) When required, the machine shall be operated at an agreed load condition.
b) Machines shall be tested in their operating position within their specified duty that
generates the greatest noise.
c) For an a.c. motor, the waveform and the degree of unbalance of the supply system shall
comply with the requirements of 6.2 of IEC 60034-1.
NOTE Any increase of voltage (and current) waveform distortion and unbalance will result in an increase
in noise.
d) A synchronous motor shall be run with excitation to obtain unity power factor or for large
machines tested as a generator.
e) A generator shall be either run as a motor or driven at rated speed with excitation to
obtain the rated voltage on open-circuit.
f) A machine suitable for more than one speed shall be evaluated over the operating speed
range.
g) A motor intended to be reversible shall be operated in both directions unless no difference
in sound power level is expected. A unidirectional motor shall be tested in its design
direction.
6 Sound power level limits
Where a machine is tested under the conditions specified in Clause 5, the sound power level
of the machine shall not exceed the relevant value(s) specified as follows:
a) A machine, other than those specified in b), operating at no-load shall be as specified in
Table 1.
b) A single-speed three-phase cage induction motor with cooling classification IC01, IC11,
IC21, IC411, IC511 or IC611, at 50 Hz or 60 Hz, and with rated output not less than
1,0 kW and not exceeding 1 000 kW:
• operating at no-load shall be as specified in Table 2;
• operating at rated load shall be the sum of the values established in Tables 2 and 3.

---------------------- Page: 11 ----------------------
– 10 – 60034-9  IEC:2003+A1:2007
Converter-supplied a.c. machines are excluded from specified limits.
NOTE 1 The limits of Tables 1 and 2 recognize class 2 accuracy grade levels of measurement uncertainty and
production variations.
NOTE 2 Sound power levels, under full-load condition, are normally higher than those at no-load. Generally, if
ventilation noise is predominant the change may be small; but, if the electromagnetic noise is predominant the
change may be significant.
NOTE 3 The limits are irrespective of the direction of rotation. A machine with a unidirectional ventilator is
generally less noisy than one with a bi-directional ventilator. This effect is more significant for high speed
machines, which may be designed for unidirectional operation only.
NOTE 4 For some machines, the limits in Table 1 may not apply for speeds below nominal speed. In such a case,
or where the relationship between noise level and load is important, limits should be agreed between the
manufacturer and the purchaser.
NOTE 5 For multispeed machines the values in the Table 1 apply.
7 Determination of noise increments caused by converter supply
Noise emissions of electromagnetic origin at the converter supply can be considered as the
superposition of:
• the noise generated by the voltages and currents of fundamental frequency, which is
identical with the noise at sinusoidal supply of the same values, and
• an increment caused by voltages and currents at other frequencies.
Two features mainly influence this increment:
a) The frequency spectrum at the converter terminals
Three typical frequency spectra can be identified:
1) Spectrum of a block-type current-source converter

120 %
100 %
80 %
Frequency spectrum of the currents
60 %
at the output terminals of a 6-pulse
current-source converter
40 %
f = 50 Hz
1
20 %
0 %
0 300 600 900 1 200 1 500 1 800 2 100 2 400
Frequency  Hz
IEC  337/07


2) Spectrum of type A voltage-source converter (characterized by pronounced spikes CLOSE
to the switching frequency and its multiples)

Current  %

---------------------- Page: 12 ----------------------
60034-9  IEC:2003+A1:2007 – 11 –


120 %
100 %
Frequency spectrum of the voltages
80 %
at the terminals of a type A voltage-source
60 %
converter
40 %
f = 50 Hz, f = 3 kHz
1 s
20 %
0 %
0 1 000 2 000 3 000 4 000 5 000
500 1 500 2 500 3 500 4 500
Frequency  Hz
IEC  338/07

3) Spectrum of type B voltage-source converter (characterized by a broad voltage spectrum
without pronounced spikes.)

120 %
100 %
80 %
Frequency spectrum of the voltages
60 % of a type B voltage-source converter
f = 50 Hz, f average = 4,5 kHz
1 s
40 %
20 %
0 %
0 1 000 2 000 3 000 4 000 5 000
500 1 500 2 500 3 500 4 500
Frequency  Hz IEC  339/07

Specific considerations are necessary when the spectrum deviates significantly from a typical
spectrum.
b) The resonance frequencies of the motor for the modes of vibration caused
by the harmonics
The relevant resonance frequencies of motors can be grouped according to the following
table:
Shaft height H Resonance frequencies of vibration mode r
r = 0 r = 2 r = 4 r = 6
H ≤ 200 mm > 4 000 Hz > 600 Hz > 4 000 Hz > 5 000 Hz
H ≥ 280 mm < 3 000 Hz < 500 Hz < 2 500 Hz < 4 000 Hz

A magnetically excited tone is generated by the interaction of the fundamental fields of the
number of pole-pairs p of the fundamental frequency f at the motor terminals and of one of
1
the harmonic frequencies n ∙ f , as shown in the relevant frequency spectrum. The tones are
1
of:
(n+ 1)⋅ f
1
frequencies
f = f ⋅ (n± 1)=
r 1
(n− 1)⋅ f
1
2p
vibration modes r= p± p=
0

Voltage  %
Voltage  %

---------------------- Page: 13 ----------------------
– 12 – 60034-9  IEC:2003+A1:2007
Usually combinations with n ∙ f , close to the switching frequency generate objectionable
1
tones.
A reasonable increase of the audible noise is to be expected, if the frequency and the
vibration mode of a tone are close to the corresponding values of the resonant structure of the
motor. In some cases, objectionable tones may be avoided by changes to the parameter
assignment of the converter.
The following table shows the expected increase of noise, at converter supply, when
compared to the noise at sinusoidal supply, with the same fundamental values of voltage and
frequency.
Increments of noise
Kind of converter Case Expected increment
1 to 5 dB(A)
The higher values relate to motors
Block-type current-source converter 6-pulse or 12-pulse
with low ventilation noise.
Increment depends on load.
Up to 15 dB(A)
High frequency voltages of high
Increment does not depend on load.
amplitudes excite resonances of the
Initial calculation possible by
motor
Type A
adequate software.
voltage-source converter
High frequency voltages of high 1 to 5 dB(A)
amplitudes do not excite resonances
Increment does not depend on load.
of the motor
5 to 10 dB(A)
Type B Broad voltage spectrum without
voltage-source converter pronounced spikes
Increment does not depend on load.

8 Determination of sound pressure level
Sound pressure levels are not required as part of this Standard. If requested, an A-weighted
sound pressure level may be determined directly from the sound power level as follows:

...

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