IEC 63522-2:2025

IEC 63522-2 ®
Edition 1.0 2025-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays – Tests and measurements –
Part 2: Mechanical tests and weighing

Relais électriques – Essais et mesurages –
Partie 2 : Essais mécaniques et pesage
ICS 29.120.70  ISBN 978-2-8327-0458-5

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– 2 – IEC 63522-2:2025 © IEC 2025
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references. 5
3 Terms and definitions . 5
4 Test procedure . 6
4.1 Mechanical tests . 6
4.1.1 Purpose . 6
4.1.2 Procedure . 6
4.1.3 Conditions to be specified . 11
4.2 Weighing. 11
4.2.1 Purpose . 11
4.2.2 Procedure . 11
4.2.3 Conditions to be specified . 12
5 Evaluation . 12
5.1 General . 12
5.2 Test report . 12
5.2.1 General . 12
5.2.2 Mechanical tests report . 12
5.2.3 Weighing report . 12
Annex A (informative) Diagram of typical relay test level . 13
Bibliography . 16

Figure 1 – Parameter schematic diagram based on force-displacement curve . 8
Figure 2 – Diagram of clapper-type relay test level . 9
Figure A.1 – Diagram of direct acting relay test level . 13
Figure A.2 – Diagram of balanced armature relay test level . 14
Figure A.3 – Diagram of balanced force relay test level . 15

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL RELAYS –
TESTS AND MEASUREMENTS –
Part 2: Mechanical tests and weighing

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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IEC 63522-2 has been prepared by IEC technical committee 94: Electrical relays. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
94/1125/FDIS 94/1151/RVD
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 63522-2:2025 © IEC 2025
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 of the IEC 63522 series, published under the general title Electrical relays –
Tests and measurements, 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.
ELECTRICAL RELAYS –
TESTS AND MEASUREMENTS –
Part 2: Mechanical tests and weighing

1 Scope
This part of IEC 63522 is used for testing all kinds of electrical relays and for evaluating their
ability to perform under expected conditions of transportation, storage and all aspects of
operational use.
NOTE Examples for electrical relays in the sense of this document include electromechanical relays, reed relays,
reed contacts, reed switches, solid state relays, time relays and technology combinations of these.
This document defines a standard test method to ensure that particular mechanical properties
(such as contact force, armature travel, contact gaps) and weight, are within specified limits.
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 63522-0:–, Electrical relays – Tests and measurements – Part 0: General and guidance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 63522-0 and the
following apply.
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
contact force
force which two contact members exert against each other at their contact points in the closed
position
Note 1 to entry: The contact force can be obtained by the F-D curve or by direct measurement.
[SOURCE: IEC 60050-444:2002, 444-04-10, modified – Note to entry added.]
___________
Under preparation. Stage at the time of publication: IEC CDV 63522-0:2024.

– 6 – IEC 63522-2:2025 © IEC 2025
3.2
contact gap
gap between the contact points when the contact circuit is open
[SOURCE: IEC 60050-444:2002, 444-04-09]
3.3
armature travel
distance (angle) which the armature moves from its initial position to the final position when the
relay is energized
Note 1 to entry: Armature travel is also called "Armature stroke".
3.4
contact overtravel
distance which a contact piece would move from first closing until final position (when the
opposing contact piece would allow the movement)
Note 1 to entry: Contact overtravel is also called "Follow of contact" or "Contact follow".
3.5
F-D curve
force-displacement curve
curve which represents the relationship between a force (F) in an electromagnetic system (or a
reed system) and a related displacement (D) in this system
3.6
counter force
force in a reed (or spring) system (at contact or armature) without influence of the magnetic
system
4 Test procedure
4.1 Mechanical tests
4.1.1 Purpose
To ensure that particular mechanical properties (for example contact force, armature travel,
contact gaps) of relays are within specified limits.
4.1.2 Procedure
4.1.2.1 General
On the basis of ensuring the accuracy of the test, other test procedures that are more suitable
for the relay under test can be adopted.
NOTE The force-displacement measurement is usually used for complex tests when it is necessary to test contact
force and moving displacement of contact at the same time to obtain the force-displacement curve (F-D curve).

Key:
1 armature position coil unenergized
2 NC contact opening
3 NO contact closing
4 end position of closed contact
a) Example of F-D curve for change over (CO) relay

Key:
1 armature position coil unenergized
2 NO contact closing
3 end position of closed contact
b) Example of F-D curve for normally open (NO) relay

– 8 – IEC 63522-2:2025 © IEC 2025

Key:
1 armature position coil unenergized
2 NC contact opening
3 end position of closed contact
c) Example of F-D curve for normally closed (NC) relay

Figure 1 – Parameter schematic diagram based on force-displacement curve

a) Initial position
b) End position
Key
1,3: stationary contact
2: movable contact
4: pusher arm
5: yoke
6: iron core
7: coil
8: Armature
Figure 2 – Diagram of clapper-type relay test level
4.1.2.2 Contact force
4.1.2.2.1 General
The contact force can be obtained by graphical extrapolation of the force-distance curve
(Method 1) or direct measurement at contact point or armature (Method 2).

– 10 – IEC 63522-2:2025 © IEC 2025
4.1.2.2.2 Method 1
The data of force and distance of counter force curve (red lines shown in Figure 1, one type of
F-D curves) can be obtained using the force detector of the force-displacement test system (or
force meter) moving along the whole travel of the relay.
For CO relays which have NO contacts, the contact force can be calculated as shown in
Figure 1 a) according to the F-D curve. The difference between point 4 and the extension line
of the ligature between point 2 and point 3 is the NO contact force, and for NC contacts, the
contact force can be calculated as shown in Figure 1 a) according to the F-D curve. The
difference between point 1 and the extension line between point 3 and point 2 is the NC contact
force.
For NO relays which only have NO contacts, the contact force can be calculated as shown in
Figure 1 b) according to the F-D curve. The difference between point 3 and the extension line
between point 1 and point 2 is the NO contact force.
For NC relays which only have NC contacts, the contact force can be calculated as shown in
Figure 1 c) according to the F-D curve. The difference between point 1 and the extension line
between point 3 and point 2 is the NC contact force.
4.1.2.2.3 Method 2
Use a force meter to make the movable contact move on contact point level or on armature
level as shown in Figure 2 (or Annex A). The point of measurement shall be specified.
For NO contacts, energize the coil with rated voltage and then measure the contact force when
the two parts of contacts closed.
For NC contacts, measure the contact force in deenergized/release condition.
For CO contacts, measure the contact force at the initial position (as shown in Figure 2 a))
firstly, then energize the coil with rated voltage to make the movable contact at the end position
(as shown in Figure 2 b)) and measure the contact force.
The force meter shall be selected according to the relay to be tested and the contact force limit
value.
The speed of force meter action during the test shall not affect the test results.
The test point should be at the end of the armature and the position should be the same for
each relay.
NOTE The test force is tested from the armature which has a torque transfer relationship from the force at the
contact points; the real contact force will be calculated in some cases.
4.1.2.3 Armature travel
4.1.2.3.1 Method 1
The armature travel can be read from the displacement value according to the F-D curve.
In some cases, it is necessary to convert data to the contact level according to the specific
structure of the relay.
4.1.2.3.2 Method 2
Connect the terminals of the contact set of the tested relay to the contact monitoring device,
insert a feeler gauge between the armature and the yoke; the relay shall be energized with
rated voltage. Change the feeler gauge thickness and monitor the action of contact to determine
the armature travel value.
4.1.2.4 Contact gaps
4.1.2.4.1 Method 1
The contact travel can be calculated from the displacement value from Point 2 to Point 3
according to the F-D curve.
4.1.2.4.2 Method 2
For NO contacts, coil de-energized, place the gauge between the tested contacts and determine
the contact gaps value.
For NC contacts, coil energized with rated voltage, place the gauge between the tested contacts
and determine the contact gaps value.
For CO contacts, place the gauge between the tested NO contacts and determine the NO
contact gaps value. Then energize the coil with rated voltage to make the movable contact
changed over, place the gauge between the tested NC contacts and determine the NC contact
gaps value.
During the test, no external force shall be applied to the reed or contact of the relay. The gauge
is in the natural falling state, and the value of the minimum diameter gauge that can just make
the contact circuit closed is used.
The gauge shall be selected according to the relay to be tested and the contact gaps limit value.
NOTE As an option, the optical method or X-ray can be used.
4.1.3 Conditions to be specified
The conditions to be specified are the following:
a) mechanical properties to be tested;
b) mounting direction;
c) required results and tolerances;
d) rated energization value, if required.
4.2 Weighing
4.2.1 Purpose
To ensure that the weights of relays are within specified limits.
4.2.2 Procedure
Select the balance weight or digital scale or other equipment to get the weight of the relay(s).
The speed of action during the test shall not affect the test results.
The test equipment shall be selected according to the relay to be tested and the weight limit
value.
– 12 – IEC 63522-2:2025 © IEC 2025
4.2.3 Conditions to be specified
The conditions to be specified are the following:
a) for the test equipment, the precision class of test equipment is recommended to be higher
than ±0,1 %;
b) weight of the relay and tolerances.
5 Evaluation
5.1 General
The measurement results shall be within the tolerance range of the specified values.
5.2 Test report
5.2.1 General
If this part of the lEC 63522 series is executed as a part of a test record of another standard,
then the results shall be reported as required in the other standard.
Otherwise, it is recommended to issue a dedicated test report according to this document.
The test report shall contain all the information necessary to reproduce the test. ln particular,
the following shall be recorded.
5.2.2 Mechanical tests report
The mechanical tests report shall consist of the following:
a) the number of samples;
b) the level of where to measure;
c) the data measured.
5.2.3 Weighing report
The weighing tests report shall consist of the following:
a) the number of samples;
b) the data measured.
...