IEC 60255-21-2

SLOVENSKI STANDARD
SIST IEC 60255-21-2:1995
01-avgust-1995
Electrical relays - Part 21: Vibration, shock, bump and seismic tests on measuring
relays and protection equipment - Section 2: Shock and bump tests
Electrical relays - Part 21: Vibration, shock, bump and seismic tests on measuring relays
and protection equipment - Section Two: Shock and bump tests
Relais électriques - Vingt et unième partie: Essais de vibrations, de chocs, de secousses
et de tenue aux séismes applicables aux relais de mesure et aux dispositifs de protection
- Section deux: Essais de chocs et de secousses
Ta slovenski standard je istoveten z: IEC 60255-21-2
ICS:
29.120.70 Releji Relays
SIST IEC 60255-21-2:1995 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST IEC 60255-21-2:1995

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SIST IEC 60255-21-2:1995
NORME CEI
IEC
INTERNATIONALE
255-21-2
INTERNATIONAL
Première édition
STAN DARD
First edition
1988-10
Relais électriques
Partie 21:
Essais de vibrations, de chocs, de secousses et
de tenue aux séismes applicables aux relais de
mesure et aux dispositifs de protection
Section deux — Essais de chocs et de secousses
Electrical relays
Part 21:
Vibration, shock, bump and seismic tests on
measuring relays and protection equipment
Section Two — Shock and bump tests
de reproduction réservés — Copyright - all rights reserved
© IEC 1988 Droits
de publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
Aucune partie cette
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l'accord écrit l'éditeur writing from the publisher.
copie et les microfilms, sans de
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IEC
catalogue en vigueur
Pour prix, voir
•
For price, see current catalogue

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SIST IEC 60255-21-2:1995
© - 3 -
255-21-2 IEC
CONTENTS
Page
FOREWORD 5
PREFACE 5
Clause
1. Scope 7
7
Object 2.
Definitions 7
3.
3.1 Shock test 9
9
3.2 Shock response test
3.3 Shock withstand test 9
3.4 Bump test 9
9
Requirements for shock and bump tests
4.
9
4.1 Test apparatus and mounting
13 4.2 Shock test severity classes
15 4.3 Bump test severity classes
Recommendations for the selection of shock and
4.4
17
bump test severity classes
17 4.5 Test procedure for shock response test
4.6 Test procedure for shock withstand test and
21
bump test
21 5. Criteria for acceptance
21
Acceptance criteria for shock response test 5.1
Acceptance criteria for shock withstand test and
5.2
23
for bump test
25 FIGURES
APPENDIX A - Selection criteria for shock and bump test
and output circuit response
parameters a)
29
b) during shock response test

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SIST IEC 60255-21-2:1995
255-21-2 © IEC - 5 -
INTERNATIONAL ELECTROTECHNICAL COMMISSION
ELECTRICAL RELAYS
Part 21: Vibration, shock, bump and seismic tests
on measuring relays and
protection equipment
Section Two - Shock and bump tests
FOREWORD
1) The formal decisions or agreements of the IEC 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 IEC expresses the wish that all
National Committees should adopt the text of the IEC recommendation for their national
rules in so far as national conditions will permit. Any divergence between the IEC recom-
mendation 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 41B: Measuring
relays and protection equipment, of IEC Technical Committee No. 41:
Electrical relays.
The text of this standard is based on the following documents:
Six Months' Rule Report on Voting
41B(CO)4l
41B(CO)38
Full information on the voting for the approval of this standard can be
found in the Voting Report indicated in the above table.
The following IEC publications are quoted in this standard:
Publications Nos. 68-2-27 (1987): Basic environmental testing procedures, Part 2: Tests
Test Ea and guidance: Shock.
68-2-29 (1987): Test Eb and guidance: Bump.
255-7 (1978): Electrical relays, Part 7: Test and measurement pro-
cedures for electromechanical all-or-nothing relays.
255-21-1 (1988): Part 21: Vibration, shock, bump and seismic tests on
measuring relays and protection equipment - Section
One: Vibration tests (sinusoidal).
(Being printed.)
Other publication quoted:
ISO Standard 2041 (1975): Vibration and shock - Vocabulary.

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SIST IEC 60255-21-2:1995
255-21-2 © IEC - 7 -
ELECTRICAL RELAYS
Part 21: Vibration, shock, bump and seismic tests
on measuring relays and
protection equipment
SECTION TWO - SHOCK AND BUMP TESTS
1. Scope
This standard is part of a series specifying the vibration, shock,
bump and seismic requirements applicable to electromechanical and
static measuring relays and protection equipment with or without
output contacts.
This standard includes two types of test:
- the shock test (on energized and non-energized specimen);
- the bump test (on non-energized specimen),
and is generally based on IEC 68-2-27 and 68-2-29.
The requirements of this standard are applicable only to measuring
relays and protection equipment in new condition. The tests specified
in this standard are type tests.
2. Object
The object of this standard is to state:
- definitions of terms used;
- test conditions;
standard test severity classes;
- test procedure;
- criteria for acceptance.
3. Definitions
For definitions of general terms not defined in this standard,
reference should be made to:
- International Electrotechnical Vocabulary (IEV) [IEC 50];
- IEC 68-2-27 and 68-2-29;
- relay standards published in the IEC 255 series;
- ISO 2041;
Section One: Vibration tests (sinusoidal) [IEC 255-21-1].
For the purpose of this standard the following definitions shall
apply:

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SIST IEC 60255-21-2:1995
255-21-2 © IEC - 9
Shock test
3.1
A test during which a specimen, non-energized or energized under
specified conditions, is subjected to a limited number of single shocks,
in the three different axes of the specimen in turn, to determine its
capability to withstand the effects of shocks.
The term "specimen" includes any auxiliary part which is an
Note.-
integral functional feature of the measuring relay or protec-
tion equipment under test.
3.2 Shock response test
A shock test carried out on a measuring relay or protection equip-
ment, energized under specified conditions, to determine its response
to shocks likely to be occasionally encountered in service.
Shock withstand test
3.3
A high level shock test carried out on a non-energized measuring
relay or protection equipment to determine its capability to withstand
shocks likely to be occasionally encountered during transportation and
handling.
3.4 Bump. test
A test during which a non-energized measuring relay or protection
equipment is subjected to a limited number of bumps, in three
different axes of the specimen in turn, to determine its capability to
withstand the effects of bumps likely to be encountered during trans-
portation.
4. Requirements for shock and bump tests
The main parameters of the shock and bump tests are the following:
- acceleration;
- duration of the nominal pulse;
- number of pulses applied.
In this standard the pulse shape used is one half-cycle of a sine
wave.
4.1 Test apparatus and mounting
The required characteristics of the shock and bump generators and
fixtures together with the mounting requirements shall be as specified
in the following sub-clauses.
The characteristics shall apply when the specimen is mounted on the
generator.
4.1 .1 Acceleration tolerances
The nominal pulse shape for shock and bump tests shall be one
half-cycle of a sine wave, as indicated by the dotted line shown in
Figure 1.

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SIST IEC 60255-21-2:1995
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The true value of the actual acceleration shall be within the toler-
ance limits indicated by the solid lines shown in Figure 1.
4.1.2 Pulse duration tolerances
The actual pulse duration shall be the nominal value within a toler-
±2
ance of ms.
4.1.3
Transverse motion
The positive or negative peak acceleration at the monitoring point,
perpendicular to the intended shock or bump direction, shall not
exceed, at any time, 30% of the value of the peak acceleration of the
nominal pulse in the intended direction, when determined by a measur-
ing system in accordance with Sub-clause 4.1.5.
4.1.4 Repetition rate
During shock and bump tests, the repetition rate shall be such that
between applied pulses the relative motion within the specimen shall be
substantially zero and the value of acceleration at the reference point
shall be within the limits shown in Figure 1.
Note.- For the bump test a rate of one to three pulses per second is
usually adequate.
4.1 .5 Measuring system
The shock and bump pulse shall be measured by an accelerometer
placed at the reference point, which shall be declared by the manu-
facturer.
The characteristics of the measuring system shall be such that it can
be determined that the true value of the actual pulse, as measured in
the intended direction at the reference point, is within the tolerances
required by the Sub-clauses 4.1.1 and 4.1.2.
The frequency response of the overall measuring system, including the
accelerometer, can have a significant effect on the accuracy and shall
be within the limits shown in Figure 2 for shock and bump tests.
4.1.6 Mounting
The specimen shall be fastened to the shock or bump generator or
fixture by its normal means of attachment in service, such that the
gravitational force acts on it in the same relative direction as it would
in normal use.
During the shock response test, cable connections to the specimen
shall be so arranged that they impose no more restraint or mass than
they would when the specimen is installed in its operating position.
Note.- Care should be taken to ensure that the specimen under test is
not significantly affected by any magnetic field generated by
the test system.

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SIST IEC 60255-21-2:1995
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4.2 Shock test severity classes
This standard includes two types of shock tests:
- shock response test on an energized relay or protection equipment;
- shock withstand test on a non-energized relay or protection
equipment.
Both shock response test and shock withstand test include three
different severity classes (0, 1, 2) the main parameters of which are
referred to in Sub-clauses 4.2.1 and 4.2.2 below.
For particular types of measuring relays or protection equipment,
the manufacturer may declare different severity classes for shock
res
...