EN 60068-2-7:1993

SLOVENSKI STANDARD
01-september-2001
Basic environmental testing procedures - Part 2: Tests - Test Ga and guidance:
Acceleration, steady state
Environmental testing -- Part 2: Tests - Test Ga: Acceleration, steady state
Grundlegende Umweltprüfverfahren -- Teil 2: Prüfungen - Prüfung Ga und Leitfaden:
Gleichförmiges Beschleunigen
Essais d'environnement. Deuxième partie: Essais. Essai Ga: Accélération constante
Ta slovenski standard je istoveten z: EN 60068-2-7:1993
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE
IEC
60068-2-7
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1983-01
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Essais fondamentaux climatiques
et de robustesse mécanique –
Partie 2-7:
Essais – Essai Ga et guide:
Accélération constante
Basic environmental testing procedures –
Part 2-7:
Tests – Test Ga and guidance:
Acceleration, steady state
CODE PRIX
L
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur

68-2-7 © I E C 1983 — 3 —
CONTENTS
Page
FOREWORD 5
PREFACE 5
Clause
1. Object 9
2. General . 9
3. Conditions for testing 9
4. Severity 11
5.
Initial measurements 13
6.
Conditioning: procedure for testing with a cent rifuge 13
7. Final measurements 13
8. Information to be given in the relevant specification 13
APPENDIX
A — Guidance 17
APPENDIX B — Additional guidance 21

68-2-7 ©
I EC 1983 — 5 —
INTERNATIONAL ELECTROTECHNICAL COMMISSION
BASIC ENVIRONMENTAL TESTING PROCEDURES
Part
2: Tests — Test Ga and guidance: Acceleration, steady state
FOREWORD
1) The formal decisions or agreements of the I EC on technical matters, prepared by Technical Committees on which
all the National Committees having a special interest therein are represented, express, as nearly as possible, an
international consensus of opinion on the subjects dealt with.
2) They have the form of recommendations for international use and they are accepted by the National Committees in
that sense.
3) In order to promote international unification, the I E C expresses the wish that all National Committees should adopt
the text of the I EC recommendation for their national rules in so far as national conditions will permit. Any
divergence between the I EC recommendation and the corresponding national rules should, as far as possible, be
clearly indicated in the latter.
PREFACE
This standard has been prepared by Sub-Committee 50A: Shock and Vibration Tests, of
I E C Technical Committee No. 50: Environmental Testing.
It forms the second edition of I E C Publication 68-2-7: This second edition combines the
texts of the first edition (1968) and its first amendment (1982), and incorporates minor
editorial amendments to take account of the transfer of the requirements for mounting for test
to IEC Publication 68-2-47: Basic Environmental Testing Procedures, Part 2: Tests – Mounting
of Components, Equipment and Other A rticles for Dynamic Tests Including Shock (Ea), Bump
(Eb), Vibration (Fc and Fd) and Steady-state Acceleration (Ga) and Guidance.
Drafts of the first edition of Test Ga were discussed at the meetings held in Aix -les-Bains
in 1964, in Tokyo in 1965 and in London in 1966. As a result of this latter meeting, a draft,
Document 50A(Central Office)118, was submitted to the National Committees for approval
under the Six Months' Rule in March 1967.
The National Committees of the following countries voted explicitly in favour of publication
of the first edition:
Netherlands
Australia
Norway
Austria
Belgium South Africa (Republic of)
Canada Sweden
Czechoslovakia Switzerland
Denmark Turkey
Union of Soviet
France
Germany Socialist Republics
Israel United Kingdom
Japan
68-2-7 © IEC:1983 – 7 –
A draft concerning Appendix B: Additional guidance, was discussed at the meeting held in
Moscow in 1977. As a result of this meeting, a draft, Document 50A(Central Office)151, was
submitted to the National Committees for approval under the Six Months' Rule in February
1980.
It has the status of a basic safety publication in accordance with IEC Guide 104.
The National Committees of the following countries voted explicitly in favour ofpublication:
Australia New Zealand
Belgium Norway
Brazil Poland
Canada Romania
Denmark South Africa (Republic of)
Egypt Spain
Finland Switzerland
Germany Turkey
Hungary Union of Soviet
Israel Socialist Republics
Korea (Republic of) United Kingdom
Netherlands United States of America
Other IEC publications quoted in this standard:
Publication Nos. 68-1: Basic Environmental Testing Procedures. Part 1: General and
Guidance.
68-2-47: Basic Environmental Testing Procedures. Part 2: Tests – Mounting
of Components, Equipment and other Articles for Dynamic Tests Including
Shock (Ea), Bump (Eb),Vibration (Fc and Fd) and Steady-state Acceleration
(Ga) and Guidance.
721: Classification of Environmental Conditions.

–––––––––––––––
68-2-7 © I EC 1983 — 9 _
BASIC ENVIRONMENTAL TESTING PROCEDURES
Part 2: Tests — Test Ga and guidance: Acceleration, steady-state
1. Object
To prove the structural suitability and the satisfactory performance of components,
equipment and other electrotechnical products, hereinafter referred to as "specimens",
when subjected to forces produced by steady acceleration environments (other than
gravity) such as occur in moving vehicles, especially flying vehicles, rotating pa rts and
projectiles, and to provide a test of structural integrity for ce rtain components.
2. General
Equipment, components and other electrotechnical products intended to be installed in
moving bodies will be subjected to forces caused by steady accelerations. Naturally, such
an environment is most pronounced in flying vehicles and rotating machinery, although
in cert
ain conditions accelerations in land vehicles may be of significant magnitude.
In general, the accelerations encountered in service have different values along each of
the major axes of the moving body, and, in addition, usually have different values in the
opposite senses of each axis.
If the attitude of the specimen is not fixed with regard to the moving body, then the
relevant specification should prescribe a level, which may be applied along each of the
major axes and senses of the specimen, having taken into account the maximum
accelerations in different axes of the moving body.
This standard is to be used in conjunction with IEC Publication 68-1: Basic
Environmental Testing Procedures, Pa rt 1: General and Guidance.
3. Conditions for testing
3.1
Characteristics of the test apparatus
3.1.1 General
Acceleration conditions are applied by means of a centrifuge where the acceleration is
directed towards the centre of the rotating system. In ce rtain special cases, however, the
specimen may be sensitive to gyroscopic couples, and it may only be possible to perform
the test by using a machine capable of applying linear acceleration, in which case the
relevant specification shall state this requirement.
3.1.2 Tangential acceleration
When increasing the rotational speed of a centrifuge from zero to the value necessary
to achieve the specified acceleration, or when decreasing back to zero, the machine shall
be so controlled that the specimen is not subjected to a value of tangential acceleration
greater than 10% of the specified acceleration.

68-2-7 © I EC 1983 . — 11 —
3.1.3 Acceleration gradient
rt of
The dimensions of a cent rifuge relative to the specimen shall be such that no pa
the specimen, other than flying leads, shall be subjected to a value of acceleration
outside the tolerances given in Sub-clause 3.1.4.
3.1.4 Acceleration tolerance
If the linear dimensions of the specimen are less than 10 cm, the acceleration on all
parts of the specimen (excluding flying leads) shall not depart from the specified
steady-state acceleration by more than ± 10%.
In other cases, the tolerance on the specified steady-state acceleration is —10 % +30%.
3.2 Mounting
The specimen shall be mounted on the test apparatus in accordance with the
requirements in I E C Publication 68-2-47: Basic Environmental Testing Procedures. Part 2:
Tests — Mounting of Components, Equipment and Other Articles for Dynamic Tests
Including Shock (Ea), Bump (Eb), Vibration (Fc and Fd) and Steady-state Acceleration
(Ga) and Guidance.
For reasons of safety, care should be taken to prevent the specimens under test from being thrown off
Note. —
if the mounting attachments are broken but any safety devices used should not introduce additional
constraint during the test.
4.
Severity
The relevant specification shall prescribe an acceleration value for the test, chosen,
where possible, from the standard values listed below. It shall also prescribe the angle,
with respect to the axes of the specimen, at which this acceleration is to be applied,
where it is necessary (Clauses Al, A2 and B2).
The value prescribed for the acceleration should take into account the purpose of the test, whether it is
Note. —
to be made for checking the structural integrity of the specimen or to assess the ability of the specimen
to withstand the forces occurring in moving vehicles or rotating machinery.
The standard levels of test are:
Acceleration
Equivalent values
m/s2
gg
196 20
1 960 200
4 900
9 800 1 000
2 000
19 000
5 000
49 000
98 000 10 000
20 000
196 000
294 000 30 000
68-2-7 © I EC 1983 — 13 —
5. Initial measurements
The specimen shall be submitted to the visual, dimensional and functional checks
prescribed by the relevant specification.
6. Conditioning: procedure for testing with a centrifuge
6.1 Unless otherwise stated in the relevant specification, the acceleration conditioning shall be
imposed in both senses of three mutually perpendicular axes in turn, which shall be the
three major axes.
6.2 The centrifuge shall be rotated at the speed necessary to produce the specified level.
6.3 The necessary speed of rotation shall be maintained for not less than 10 s or for a
period stated in the relevant specification.
6.4 The relevant specification shall prescribe which of the following conditions of functioning
or survival has to be satisfied and the corresponding acceleration level(s) (Clause A2):
1) Specimen to function within the performance limits given in the relevant specification.
2) Specimen to function, but not necessarily within the performance limits, but should
suffer no permanent derangement.
3) Specimen not to suffer any permanent derangement, but need not function.
4) Specimen not to break loose, although it may be permanently damaged or deranged.
6.5 The relevant specification shall prescribe the order in which the checks in Sub-clause 6.4
are to be applied (Clause A2).
7. Final measurements
The specimen shall be submitted to the visual, dimensional and functional checks as
prescribed by the relevant specification.
Information to be given in the relevant specification
8.
When this test is included in a relevant specification, the following details shall be
given as far as they are applicable:

Sub-clause 3.1
a) Type of test apparatus
b) and c) Methods of mounting the specimen Sub-clause 3.2

Clause 4
d) Acceleration level(s) (Clauses A2 and B2)

Clauses 4, 6
e) Axes and direction of acceleration (Clause Al)

— 15 —
68-2-7 © I EC 1983
Clause 5
j)
Initial measurements
Sub-clause 6.3
g) Duration of conditioning
Sub-clause 6.4
h) Conditions of functioning or survival (Clause B1)
Sub-clause 6.5
j) Order of checks
Clause 7
Final measurements
k)
68-2-7 © I EC 1983 — 17 —
APPENDIX A
GUIDANCE
Al. Specimen orientation for test
In many applications, especially aircraft, the forces on the moving body giving rise to
acceleration are invariably complex but can be considered, at any instant, to be a single
force which can be described in direction by its angular position relative to the three
main axes of the moving body. For design purposes, the maximum acceleration levels for
a particular manoeuvre of the moving body are resolved and specified with respect to
each major axis of the moving body.
If a specimen has a known fixed attitude with respect to a given moving body, and in
cases where it is necessary to simulate the three components of acceleration simul-
taneously, these can be combined and the specimen subjected to a single acceleration
equal in magnitude and direction to the resultant of the three component levels. Such
action would necessitate rather complicated jigs, in order to orientate a specimen relative
to the test machine in such a manner that the acceleration is directed along the line of
the resultant. Unless it is important to preserve the angular relationship between the
resultant acceleration and the specimen, it is simpler and usually adequate to apply the
resultant acceleration along the major axis of the specimen having the highest of the
three specified component levels; in the remaining axes the appropriate component
acceleration levels would be applied.
to the vehicle is not known, the
When the attitude of the specimen with respect
maximum resultant level for the particular moving body should be applied in each
direction in turn along each of the three major axes of the specimen.
A2. Acceleration levels
Some of the acceleration values listed in Clause 4 represent actual environments and
others, especially at the higher levels, represent artificial environments used for the
structural integrity testing of some electronic components. Bearing in mind the high
acceleration figures which ma
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