IEC 60938-1:1999+AMD1:2006 CSV

Fixed inductors for electromagnetic interference suppression - Part 1: Generic specification

Applies to inductors designed for electromagnetic interference suppression intended for use within, or associated with, electronic or electrical equipment and machines. It is restricted to inductors for which safety tests are appropriate. The combination of two or more inductors within one enclosure is also included. Inductors within the scope of this standard may also be used to protect apparatus and machines from electrical noise and voltage or current transients coming from either the supply or from other parts of the apparatus. It may not necessarily apply in its entirety to inductors intended for use on motor vehicles, in aircraft or for marine applications. This consolidated version consists of the second edition (1999) and its amendment 1 (2006). Therefore, no need to order amendment in addition to this publication.

General Information

• Status: Published
• Publication Date: 27-Nov-2006
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.100.10 - Magnetic components
• ICS: 31.020 - Electronic components in general
• Technical Committee: TC 40 - Capacitors and resistors for electronic equipment
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 16-Jun-2021

Standards Content (Sample)

INTERNATIONAL IEC




STANDARD 60938-1





QC 280000


Edition 2.1


2006-11



Edition 2:1999 consolidated with amendment 1:2006
Fixed inductors for electromagnetic
interference suppression –
Part 1:
Generic specification


Reference number
IEC 60938-1:1999+A1:2006(E)

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Publication numbering


As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.


Consolidated editions

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edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
amendments 1 and 2.
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INTERNATIONAL IEC




STANDARD 60938-1






QC 280000




Edition 2.1

2006-11


Edition 2:1999 consolidated with amendment 1:2006
Fixed inductors for electromagnetic
interference suppression –
Part 1:
Generic specification


© IEC 2006 ⎯ Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
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CL
Commission Electrotechnique Internationale

International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

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CONTENTS

FOREWORD.4

1 General.6

1.1 Scope.6

1.2 Normative references.6

2 Technical data .8

2.1 Units and symbols .8

2.2 Definitions.8


2.3 Preferred values .11
2.4 Marking.11
3 Quality assessment procedures .11
3.1 General.11
3.2 Primary stage of manufacture .11
3.3 Structurally similar inductors .11
3.4 Qualification approval procedures .11
3.5 Quality conformance inspection .12
3.6 Alternative test methods .12
3.7 Unchecked parameters.13
4 Test and measurement procedure.13
4.1 General.13
4.2 Standard atmospheric conditions .13
4.3 Drying.14
4.4 Visual examination and check of dimensions.14
4.5 Insulation resistance.16
4.6 Voltage proof.18
4.7 Inductance.21
4.8 Insertion loss .21
4.9 Robustness of terminations.21
4.10 Resistance to soldering heat.22
4.11 Solderability (applicable only for terminations intended to be soldered).23
4.12 Rapid change of temperature.23
4.13 Vibration.24
4.14 Bump.24
4.15 Shock.24

4.16 Container sealing.24
4.17 Climatic sequence .25
4.18 Damp heat, steady state .26
4.19 Temperature rise.26
4.20 Endurance.27
4.21 Passive flammability .27
4.22 Active flammability.28
4.23 Solvent resistance of marking .28
4.24 Component solvent resistance .28

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Annex A (normative) Interpretation of sampling plans and procedures as described

in IEC 60410 for use within the IEC quality assessment system

for electronic components (IECQ).29

Annex B (normative) Rules for the preparation of detail specifications for capacitors

and resistors for electronic equipment .30

Annex C (normative) Requirements for earth inductors.31




Figure 1 – Voltage proof test circuit .19



Table 1 – Reference test: standard atmospheric conditions .14

Table 2 – Creepage distances and clearances.15
Table 3 – Measuring voltage .16
Table 4 – Measuring points .17
Table 5 – Force.22
Table 6 – Torque.22
Table 7 – Number of cycles .26
Table 8 – Severities and requirements.28
2
Table C.1 – Rated current related to minimum cross-sectional area of copper lead (mm )
of the earth inductor .31

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



FIXED INDUCTORS FOR ELECTROMAGNETIC

INTERFERENCE SUPPRESSION –



Part 1: Generic specification





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
Publication(s)”). Their 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
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transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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
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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 60938-1 has been prepared by IEC technical committee 40:
Capacitors and resistors for electronic equipment.
This consolidated version of IEC 60938-1 consists of the second edition (1999) [documents
40/1110/FDIS and 40/1136/RVD] and its amendment 1 (2006) [documents 40/1602/CDV and
40/1699A/RVC].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 2.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
The QC number that appears on the front cover of this publication is the specification number
in the IEC Quality Assessment System for Electronic Components (IECQ).

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Annexes A, B and C form an integral part of this standard.


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.

A bilingual version of this publication may be issued at a later date.

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FIXED INDUCTORS FOR ELECTROMAGNETIC

INTERFERENCE SUPPRESSION –



Part 1: Generic specification








1 General


1.1 Scope
This International Standard applies to inductors designed for electromagnetic interference
suppression intended for use within, or associated with, electronic or electrical equipment and
machines. It is restricted to inductors for which safety tests are appropriate.
The combination of two or more inductors within one enclosure is also included.
Inductors within the scope of this standard may also be used to protect apparatus and
machines from electrical noise and voltage or current transients coming from either the supply
or from other parts of the apparatus.
This standard does not necessarily apply in its entirety to inductors intended for use on motor
vehicles, in aircraft or for marine applications.
1.2 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 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050 (all parts), International Electrotechnical Vocabulary (IEV)
IEC 60062:1992, Marking codes for resistors and capacitors
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
Amendment 1 (1992)

IEC 60068-2-1:1990, Environmental testing – Part 2: Tests – Tests A: Cold
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-2:1974, Environmental testing – Part 2: Tests – Tests B: Dry Heat
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-3:1969, Environmental testing – Part 2: Tests – Test Ca: Damp heat, steady state
Amendment 1 (1984)
IEC 60068-2-6:1995, Environmental testing – Part 2: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-13:1983, Environmental testing – Part 2: Tests – Test M: Low air pressure

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IEC 60068-2-14:1984, Environmental testing – Part 2: Tests – Test N: Change of temperature
Amendment 1 (1986)


IEC 60068-2-17:1994, Environmental testing – Part 2: Tests – Test Q: Sealing


IEC 60068-2-20:1979, Environmental testing – Part 2: Tests – Test T: Soldering
Amendment 2 (1987)


IEC 60068-2-21:1983, Environmental testing – Part 2: Tests – Test U: Robustness of
terminations and integral mounting devices
Amendment 2 (1991)

Amendment 3 (1992)
IEC 60068-2-27:1987, Environmental testing – Part 2: Tests – Test Ea and guidance: Shock
IEC 60068-2-29:1987, Environmental testing – Part 2: Tests – Test Eb and guidance: Bump
IEC 60068-2-30:1980, Environmental testing – Part 2: Tests – Test Db and guidance: Damp
heat, cyclic (12 + 12 hour cycle)
Amendment 1 (1985)
IEC 60068-2-45:1980, Environmental testing – Part 2: Tests – Test XA and guidance:
Immersion in cleaning solvents
Amendment 1 (1993)
IEC 60294:1969, Measurement of the dimensions of a cylindrical component having two axial
terminations
IEC 60335-1:1991, Safety of household and similar electrical appliances – Part 1: General
requirements
IEC 60410:1973, Sampling plans and procedures for inspection by attributes
IEC 60617 (all parts), Graphical symbols for diagrams
IEC 60695-2-2:1991, Fire hazard testing – Section 2: Needle-flame test
Amendment 1 (1994)
CISPR 17:1981, Methods of measurement of the suppression characteristics of passive radio
interference filters and suppression components

IEC QC 001002-3:1998, Rules of Procedure of the IEC Quality Assessment System for Electronic
Components (IECQ) – Part 3: Approval procedures
ISO 1000:1992, SI units and recommendations for the use of their multiples and of certain
other units

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2 Technical data


2.1 Units and symbols


Units, graphical symbols, letter symbols and terminology shall, whenever possible, be taken

from the following publications:

IEC 60027

IEC 60050

IEC 60617

ISO 1000
When further items are required they shall be derived in accordance with the principles of the
documents listed above.
2.2 Definitions
For the purpose of this International Standard, the following definitions apply.
2.2.1
type
a group of components having similar design features and the similarity of whose
manufacturing techniques enables them to be grouped together either for qualification approval
or for quality conformance inspection
They are generally covered by a single detail specification.
NOTE Components described in several detail specifications, may, in some cases, be considered as belonging to
the same type.
2.2.2
style
a sub-division of a type, generally based on dimensional factors.
A style may include several variants, generally of a mechanical order
2.2.3
family (of electronic components)
a group of electronic components which predominantly displays a particular physical attribute
and/or fulfils a defined function
2.2.4

sub-family (of electronic components)
a group of components within a family manufactured by similar technological methods
2.2.5
rated voltage (U )
R
rated voltage is either the maximum r.m.s. operating voltage of rated frequency or the
maximum d.c. operating voltage which may be applied continuously to the terminations of the
inductor at any temperature between the lower category temperature and the rated temperature
NOTE For inductors with only one winding, the rated voltage should only be applied between one terminal and any
conducting surface with which the case is liable to come into contact in normal use. For inductors having more than
one winding, the rated voltage may be applied across two individual windings.

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60938-1 © IEC:1999+A1:2006(E) – 9 –



2.2.6

category voltage (U )
C

maximum voltage which may be applied continuously to an inductor at its upper category

temperature


2.2.7

lower category temperature

minimum external surface temperature for which the inductor has been designed to operate

continuously


2.2.8
upper category temperature
maximum external surface temperature for which the inductor has been designed to operate
continuously
NOTE The external surface temperature can be affected by internal heating due to the lead-through current. The
terminations are considered to be part of the external surface.
2.2.9
rated temperature
maximum ambient temperature at which an inductor can carry its rated current
2.2.10
rated current
maximum r.m.s. operating current at rated frequency or maximum d.c. operating current which
allows continuous operation of the inductor at the rated temperature. It is assigned by the
manufacturer for one or both of the following conditions:
a) free air (I );
RO
b) with a specified heat sink (I ).
RH
2.2.11
rated inductance (L )
R
inductance value for which the inductor has been designed and which is usually indicated upon it
2.2.12
insertion loss
ratio of the voltage before and after the insertion of the suppressor in the circuit as measured
at the terminations
NOTE 1 The insertion loss can be measured either with a symmetrical or an asymmetrical test circuit.
NOTE 2 When expressed in decibels the insertion loss is 20 times the logarithm of the ratio stated.

2.2.13
asymmetrical test circuit
a test circuit in which the inductor under test is connected with a coaxial cable of which the
outer conductor constitutes a return path for high-frequency current
[CISPR 17:1981, 3.5 modified]
2.2.14
symmetrical test circuit
a test circuit in which the inductor under test is connected with screened conductor pairs in
which the asymmetrical voltage is small enough to be neglected
[CISPR 17:1981, 3.6 modified]

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2.2.15

insulated inductor

an inductor in which all terminations connected to a section may be raised to a potential

different (but not less than the rated voltage) from that of any conducting surface with which

the case is liable to come into contact in normal use


2.2.16

uninsulated inductor

an inductor in which at least one of the terminations connected to a section cannot be raised to
a potential different (but not less than the rated voltage) from that of any conducting surface

with which the case is liable to come into contact in normal use

2.2.17
electromagnetic interference suppression inductor
an inductor which at mains frequency has a low impedance, but which at radio frequency has a
high inductive impedance
NOTE 1 It may be used for reducing the interference at frequencies caused by electrical equipment.
NOTE 2 These inductors are sometimes known as RF chokes.
2.2.18
current-compensated inductor
an inductor having more than one winding on a single core arranged in such a way that the
resultant magnetization caused by the current is near zero
2.2.19
earth inductor
an inductor connected in the earth lead of an equipment.
For requirements for earth inductors, see annex C
2.2.20
thyristor inductor
an inductor used in thyristor controlled circuits
2.2.21
mains inductor
an inductor intended for direct electrical connection to the supply mains
NOTE This inductor may form part of an equipment.
2.2.22
TV choke
an inductor designed to reduce interference mainly in the frequency range 30 MHz to 300 MHz
NOTE Unencapsulated, non-current compensated TV chokes are not within the scope of this specification, but
should be considered as part of the equipment wiring.
2.2.23
visible damage
visible damage which reduces the usability of the inductor unit for intended purpose

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2.3 Preferred values

Each sectional specification shall prescribe the preferred values appropriate to the sub-family

covered by that sectional specification.


2.4 Marking


2.4.1 General


The sectional specification shall indicate the identification criteria and other information to be

shown on the inductors and the packing.

The order of priority for marking small inductors shall be specified.
2.4.2 Coding
When coding is used for tolerance or date of manufacture, the method shall be selected from
those given in IEC 60062.
3 Quality assessment procedures
3.1 General
When these standards are used for the purpose of a full quality assessment system such
as the IEC Quality Assessment System for Electronic Components (IECQ), compliance to 3.4
or 3.5 is required.
When these standards are used outside quality assessment systems for purposes such as
design proving or type testing, the procedures and requirements of 3.4.1 and 3.4.3 may be
used, but the tests and parts of tests shall be applied in the order given in the test schedules.
Before inductors can be qualified according to the procedures of this clause the manufacturer shall
obtain the approval of his organization in accordance with the provisions of IEC QC 001002-3.
For certification by an independent test laboratory the procedure of 3.4.3 shall be sufficient,
except that the test laboratory will produce the evidence of conformance.
3.2 Primary stage of manufacture
The primary stage of manufacture is the winding of the inductive element(s).
3.3 Structurally similar inductors

The grouping of structurally similar inductors for the purpose of qualification approval and
quality conformance inspection shall be prescribed in the sectional specification.
3.4 Qualification approval procedures
3.4.1 Eligibility for qualification approval
The manufacturer shall comply with 3.1.1 of IEC QC 001002-3.
3.4.2 Application for qualification approval
The manufacturer shall comply with 3.1.3 of IEC QC 001002-3.

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3.4.3 Test procedure for qualification approval

In addition to the requirements of 3.4.1 and 3.4.2, the manufacturer shall produce test evidence

to show conformance to the specification requirements on the fixed sample size test schedule

given in the sectional specification.


The specimens taken to form the sample shall be selected at random from current production

or as agreed with the National Supervising Inspectorate (NSI).


3.4.4 Granting of qualification approval


Qualification approval shall be granted when the procedures in accordance with 3.1.4 of
IEC QC 001002-3 have been completed satisfactorily.
3.4.5 Maintenance of qualification approval
Qualification approval obtained as part of a quality assessment system shall be maintained by
regular demonstration of compliance with the requirements for quality conformance (see 3.5).
3.5 Quality conformance inspection
The blank detail specification(s) associated with the sectional specification shall prescribe the
test schedule for quality conformance inspection. This schedule shall also specify the grouping,
sampling and periodicity for the lot-by-lot and periodic inspection.
Operation of the switching rule for reduced inspection in group C is permitted in all sub-groups
except endurance. Sampling plans and inspection levels shall be selected from those given
in IEC 60410.
If required, more than one schedule may be specified.
3.5.1 Certified test records of released lots
When certified test records are requested by a purchaser, they shall be specified in the detail
specification.
3.5.2 Delayed delivery
Inductors held for a period exceeding three years (unless otherwise specified in the detail
specification) following the release of the lot shall, before delivery, be re-examined as specified
in the sectional specification.

Once a lot has been satisfactorily re-inspected, its quality is re-assured for three years from the
date of re-inspection.
3.5.3 Release for delivery before the completion of group B tests
When the conditions of IEC 60410 for changing to reduced inspection have been satisfied for
all group B tests, the manufacturer is permitted to release components before the completion
of such tests.
3.6 Alternative test methods
See 3.2.3.7 of IEC QC 001002-3 with the following details:
In case of dispute, for
...