IEC 61558-2-14:2012

Safety of transformers, reactors, power supply units and combinations thereof - Part 2-14: Particular requirements and tests for variable transformers and power supply units incorporating variable transformers

IEC 61558-2-14:2012 deals with safety of variable transformers for general applications and power supply units incorporating variable transformers for general applications. Transformers incorporating electronic circuits are also covered by this standard. This first edition cancels and replaces the chapter IV of the IEC 60989 published in 1991. It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) update of the existing text;
b) complete editorial review.
This part has the status of a group safety publication in accordance with IEC Guide 104:2010. The preparation of safety publications and the use of basic safety publications and group safety publications. The attention of National Committees is drawn to the fact that equipment manufacturers and testing organizations may need a transitional period following publication of a new, amended or revised IEC publication in which to make products in accordance with the new requirements and to equip themselves for conducting new or revised tests. It is the recommendation of the committee that the content of this publication be adopted for implementation nationally not earlier than 12 months from the date of publication.
This publication is to be read in conjunction with IEC 61558-1:2005.

Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des combinaisons de ces éléments - Partie 2-14: Exigences particulières et essais pour les transformateurs variables et les blocs d'alimentation incorporant des transformateurs variables

La CEI 61558-2-14:2012 traite de la sécurité des transformateurs variables pour applications générales et des blocs d'alimentation incorporant des transformateurs variables pour applications générales. Les transformateurs incorporant des circuits électroniques sont également couverts par la présente norme. Cette première édition annule et remplace le chapitre IV de la CEI 60989 parue en 1991. Elle constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) mise à jour du texte existant;
b) revue éditoriale complète.
La présente partie a le statut de publication groupée de sécurité conformément au guide CEI 104:2010. The preparation of safety publications and the use of basic safety publications and group safety publications (disponible en anglais seulement). L'attention des Comités Nationaux est attirée sur le fait que les fabricants d'appareils et les organismes d'essai peuvent avoir besoin d'une période transitoire après la publication d'une nouvelle publication CEI, ou d'une publication amendée ou révisée, pour fabriquer des produits conformes aux nouvelles exigences et pour adapter leurs équipements aux nouveaux essais ou aux essais révisés. Le comité recommande que le contenu de cette publication soit entériné au niveau national au plus tôt 12 mois après la date de publication.
Cette publication doit être lue conjointement avec la CEI 61558-1:2005.

General Information

• Status: Published
• Publication Date: 21-Nov-2012
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TC 96 - Transformers, reactors, power supply units, and combinations thereof
• Current Stage: DELPUB - Deleted Publication
• Start Date: 31-Mar-2021
• Completion Date: 02-May-2022

Relations

• Revised: IEC 61558-2-14:2022 - Safety of transformers, reactors, power supply units and combinations thereof - Part 2-14: Particular requirements and tests for variable transformers and power supply units incorporating variable transformers for general applications
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61558-2-14
®

Edition 1.0 2012-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Safety of transformers, reactors, power supply units and combination thereof –
Part 2-14: Particular requirements and tests for variable transformers and power
supply units incorporating variable transformers

Sécurité des transformateurs, bobines d’inductance, blocs d’alimentation et des
combinaisons de ces éléments –
Partie 2-14: Exigences particulières et essais pour les transformateurs variables
et les blocs d’alimentation incorporant des transformateurs variables

IEC 61558-2-14:2012

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
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IEC 61558-2-14

®


Edition 1.0 2012-11




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE




GROUP SAFETY PUBLICATION

PUBLICATION GROUPÉE DE SÉCURITÉ




Safety of transformers, reactors, power supply units and combination thereof –

Part 2-14: Particular requirements and tests for variable transformers and power

supply units incorporating variable transformers




Sécurité des transformateurs, bobines d’inductance, blocs d’alimentation et des

combinaisons de ces éléments –


Partie 2-14: Exigences particulières et essais pour les transformateurs variables

et les blocs d’alimentation incorporant des transformateurs variables












INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX T


ICS 29.180 ISBN 978-2-83220-499-3



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

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

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– 2 – 61558-2-14 © IEC:2012
CONTENTS
FOREWORD . 3
1 Scope . 6
2 Normative references . 8
3 Terms and definitions . 8
4 General requirements . 9
5 General notes on tests . 9
6 Ratings . 10
7 Classification . 10
8 Marking and other information . 10
9 Protection against electric shock . 12
10 Change of input voltage setting . 12
11 Output voltage and output current under load . 12
12 No-load output voltage . 12
13 Short-circuit voltage . 14
14 Heating . 15
15 Short circuit and overload protection . 15
16 Mechanical strength . 15
17 Protection against harmful ingress of dust, solid objects and moisture . 16
18 Insulation resistance, dielectric strength and leakage current . 16
19 Construction . 16
20 Components . 20
21 Internal wirings . 20
22 Supply connection and other external flexible cables or cords . 20
23 Terminals for external conductors . 20
24 Provision for protective earthing . 20
25 Screws and connections . 21
26 Creepage distances, clearances and distances through insulation . 21
27 Resistance to heat, fire and tracking . 21
28 Resistance to rusting . 21
Annexes . 22
Bibliography . 23

Table 101 – Output voltages difference for auto transformers, separating and safety
isolating transformers . 14
Table 102 – Output voltages difference for isolating transformers . 14
Table 103 – Maximum permitted temperatures of the winding . 15

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61558-2-14 © IEC:2012 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATION THEREOF –

Part 2-14: Particular requirements and tests for variable transformers
and power supply units incorporating variable transformers

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-
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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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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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 61558-2-14 has been prepared by technical committee 96:
Transformers, reactors, power supply units and combination thereof.
This first edition cancels and replaces the chapter IV of the IEC 60989 published in 1991. It is a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) update of the existing text;
b) complete editorial review.

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– 4 – 61558-2-14 © IEC:2012
The text of this standard is based on the following documents:
FDIS Report on voting
96/395/FDIS 96/398/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This part has the status of a group safety publication in accordance with IEC Guide 104:2010,
The preparation of safety publications and the use of basic safety publications and group
safety publications.
This part is intended to be used in conjunction with the latest edition of IEC 61558-1 and its
amendments. It is based on the second edition (2005) of that standard and its Amendment 1
(2009).
This part supplements or modifies the corresponding clauses in IEC 61558-1, so as to convert
that publication into the IEC standard: Particular requirements and tests for variable
transformers and power supply units incorporating variable transformers.
A list of all parts of the IEC 61558 series, under the general title: Safety of transformers,
reactors, power supply units and combination thereof, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
Where a particular subclause of Part 1 is not mentioned in this part, that subclause applies as
far as is reasonable. Where this part states "addition", "modification" or "replacement", the
relevant text of Part 1 is to be adapted accordingly.
In this part, the following print types are used:
– requirements proper: in roman type;
– test specifications: in italic type;
– explanatory matter: in smaller roman type.
In the text of this part, the words in bold are defined in Clause 3.
Subclauses, notes, figures and tables additional to those in Part 1 are numbered starting from
101; supplementary annexes are entitled AA, BB, etc.
The committee has decided that the contents of this publication will remain unchanged until the
stability 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.
NOTE The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests.

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61558-2-14 © IEC:2012 – 5 –
It is the recommendation of the committee that the content of this publication be adopted for implementation
nationally not earlier than 12 months from the date of publication.

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– 6 – 61558-2-14 © IEC:2012
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATION THEREOF –

Part 2-14: Particular requirements and tests for variable transformers
and power supply units incorporating variable transformers



1 Scope
Replacement:
This part of IEC 61558 deals with safety of variable transformers for general applications and
power supply units incorporating variable transformers for general applications.
Transformers incorporating electronic circuits are also covered by this standard.
NOTE 1 Safety includes electrical, thermal, mechanical and chemical aspects.
Unless otherwise specified, from here onward, the term transformer covers variable
transformers for general applications and power supply units incorporating variable
transformers for general applications.
The rated supply voltage does not exceed 1 000 V a.c., and the rated supply frequency
does not exceed 500 Hz.
This standard is applicable to transformers and power supply units (linear) with internal
operational frequencies not exceeding 500 Hz.
This standard used in combination with Part 2-16 for switch mode power supply units
(SMPS) is also applicable to power supplies with internal operational frequencies higher than
500 Hz. Where the two requirements are in conflict the most severe take precedence
This part does not apply to transformers covered by IEC 60076-11.
This part is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural
or forced) independent or associated dry-type transformers.
– variable auto-transformers and power supply units incorporating variable auto-
transformers;
– variable separating transformers and power supply units incorporating variable
separating transformers;
– variable isolating transformers and power supply units incorporating variable isolating
transformers;
– variable safety isolating transformers and power supply units incorporating variable
safety isolating transformers.
The windings may be encapsulated or non-encapsulated.
The rated output does not exceed:
– 40 kVA for single-phase variable auto-transformers and power supply units
incorporating single-phase variable auto-transformers;

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61558-2-14 © IEC:2012 – 7 –
– 200 kVA for poly-phase variable auto-transformers and power supply units
incorporating poly-phase variable auto-transformers;
– 1 kVA for single-phase variable separating transformers and power supply units
incorporating single-phase variable separating transformers;
– 5 kVA for poly-phase variable separating transformers and power supply units
incorporating poly-phase variable separating transformers;
– 25 kVA for single-phase variable isolating transformers and power supply units
incorporating single-phase variable isolating transformers;
– 40 kVA for poly-phase variable isolating transformers and power supply units
incorporating poly-phase variable isolating transformers;
– 10 kVA for single-phase variable safety isolating transformers and power supply units
incorporating single-phase variable safety isolating transformers;
– 16 kVA for poly-phase variable safety isolating transformers and power supply units
incorporating poly-phase variable safety isolating transformers.
This part is applicable to transformers without limitation of the rated output subject to an
agreement between the purchaser and the manufacturer.
NOTE 2 Transformers intended to supply distribution networks are not included in the scope.
For variable auto-transformers and power supply units incorporating variable auto-
transformers:
– the no-load output voltage or the rated output voltage does not exceed 1 000 V a.c. or
1 415 V ripple free d.c.;
– for independent auto-transformers the rated output voltage does exceed 50 V a.c or
120 V ripple-free d.c. but not exceed 250 V a.c. .
NOTE 3 Normally, the variable auto-transformers and power supply units are intended to be associated
with the equipment to provide voltages different from the supply voltage for the functional reasons. The
protection against electric shock can be provided by other features of the equipment, such as the body.
Variable auto-transformers and power supply units incorporating variable auto-
transformers intended to be used by technically skilled or trained personnel are considered as
associated transformers and associated power supply units and may have a rated output
voltage less than 50 V a.c.
For variable separating transformers and power supply units incorporating variable
separating transformers:
– the no-load output voltage or the rated output voltage does not exceed 1 000 V a.c. or
1 415 V ripple free d.c.;
– for portable separating transormers the rated output voltage does exceed 50 V a.c or
120 V ripple-free d.c.;
– covered by this part may only be used where double or reinforced insulation between
circuits is not required by the installation rules or by the end product standard.
NOTE 4 Normally, variable separating transformers and power supply units are intended to be associated with
equipment to provide voltages different from the supply voltage for the functional reasons. The protection against
electric shock can be provided (or completed) by other features of the equipment, such as the body. Parts of
output circuits can be connected to the protective earth.
NOTE 5 Variable separating transformers and power supply units incorporating variable separating
transformers intended to be used by technically skilled or trained personal are considered as associated
transformers and associated power supply units and can have a rated output voltage less than 50 V a.c. or 120
V ripple-free d.c.
For variable isolating transformers and power supply units incorporating variable
isolating transformers:

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– 8 – 61558-2-14 © IEC:2012
– the no-load output voltage or the rated output voltage does not exceed 500 V a.c. or
708 V ripple free d.c. The no-load output voltage and the rated output voltage may be
up to 1 000 V a.c. or 1 415 V ripple free d.c. for special applications or in accordance with
national wiring rules;
– for independent isolating transformers the rated output voltage does not exceed
250 V a.c.; .
– are used where double or reinforced insulation between circuits is required by the
installation rules or by the end product standard.
For variable safety isolating transformers and power supply units incorporating safety
isolating transformers:
– the no-load output voltage or the rated output voltage does not exceed 50 V a.c. or
120 V ripple-free d.c.;
– are used where double or reinforced insulation between circuits is required by the
installation rules or by the end product standard.
This part is not applicable to external circuits and their components intended to be connected
to the input terminals and output terminals of the transformers.
NOTE 6 Attention is drawn to the following:
– for transformers intended to be used in vehicles, on board ships, and aircraft, additional requirements (from
other applicable standards, national rules, etc.) can be necessary;
– measures to protect the enclosure and the components inside the enclosure against external influences such
as fungus, vermin, termites, solar-radiation, and icing are also considered;
– the different conditions for transportation, storage, and operation of the transformers are also be considered;
– additional requirements in accordance with other appropriate standards and national rules can be applicable to
transformers intended for use in special environments, such as tropical environment.
Future technological development of transformers can necessitate a need to increase the
upper limit of the frequencies, until then this part may be used as a guidance document.
2 Normative references
This clause of Part 1 is applicable except as follows.
Addition:
IEC 61558-1:2005, Safety of power transformers, power supplies, reactors and similar products
– Part 1: General requirements and tests
Amendment 1 (2009)
3 Terms and definitions
This clause of Part 1 is applicable, except as follows:
3.1 Transformers
Addition:
3.1.101
variable transformer
transformer having unlimited numbers of transformation ratios and adjustable by means of a
movable current collector positioned along a continuous path of locally exposed winding turns

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61558-2-14 © IEC:2012 – 9 –
3.1.102
variable auto transformer
variable transformer in which input and output voltages are derived from a common winding
3.2 General terms
Addition:
3.2.101
current collector
assembly of moving contact parts which serve to transmit current from a point on the contact
path to the tapping point at the bushings or terminals
3.2.102
drive
mechanical assembly used for moving the current collector
3.2.103
fixed winding
winding or part of the winding with no means for varying the transformation ratio
3.2.104
variable winding
winding or part of the winding with a contact path used for varying the transformation ratio
3.5 Ratings
Modification:
3.5.5 is not applicable.
Addition:
3.5.101
rated output voltage range
output voltage range (for poly-phase transformer and power supply units, the phase-to-
phase voltage) at rated supply voltage, rated supply frequency, rated output current, and
rated power factor assigned to the transformer or power supply unit by the manufacturer
4 General requirements
This clause of Part 1 is applicable.
If the current collector may not stay permanently in the same position it has to be marked on
the transformer.
5 General notes on tests
This clause of Part 1 is applicable except as follows:
5.3 Addition: The test of 16.101 shall be conducted before all other tests.

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– 10 – 61558-2-14 © IEC:2012
6 Ratings
This clause of Part 1 is applicable except as follows.
Addition:
6.101 The rated output voltage shall not exceed:
– 1 000 V a.c. or 1 415 V ripple-free d.c. for variable auto- and separating transformers;
– 500 V a.c. or 708 V ripple-free d.c for variable isolating transformers; the rated output
voltage may exceed these limits in order to be in accordance with the national wiring rules,
however, it shall not exceed 1 000 V a.c. or 1 415 V ripple free d.c.;
– 250 V a.c. for portable auto-transformers, portable separating transformers and
independent isolating transformers;
– 50 V a.c. or 120 V ripple-free d.c. for variable safety isolating transformers.
This standard is also applicable for variable transformers of a rated output voltage of more
than 1 000 V a.c. or 1 415 d.c. Such transformers, however, are classified as special
transformers and are subject to agreement between purchaser and manufacturer. Such
special variable transformers have no limitation in terms of their rated output voltage.
The rated output voltage shall exceed:
– 50 V a.c. or 120 V ripple-free d.c. for variable independent auto- and independent
separating transformers.
6.102 The rated output shall not exceed the following,
– 40 kVA for single-phase variable auto-transformers;
– 200 kVA for poly-phase variable auto-transformers;
– 1 kVA for single-phase variable separating transformers;
– 5 kVA for poly-phase variable separating transformers;
– 25 kVA for single-phase variable isolating transformers;
– 40 kVA for poly-phase variable isolating transformers;
– 10 kVA for single-phase variable safety isolating transformers;
– 16 kVA for poly-phase variable safety isolating transformers.
Transformers without limitation of the rated output shall be subject to agreement between the
purchaser and the manufacturer.
6.103 The rated supply and internal operational frequencies shall not exceed 500 Hz.
6.104 The rated supply voltage shall not exceed 1 000 V a.c.
Compliance with the requireme
...