SIST EN 61558-2-20:2001

SLOVENSKI SIST EN 61558-2-20:2001
prva izdaja
STANDARD
oktober 2001
Safety of power transformers, power supply units and similar devices - Part 2-20:
Particular requirements for small reactors (IEC 61558-2-20:2000)
ICS 29.180 Referenčna številka
SIST EN 61558-2-20:2001(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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NORME CEI
INTERNATIONALE IEC
61558-2-20
INTERNATIONAL
Première édition
STANDARD
First edition
2000-06
PUBLICATION GROUPÉE DE SÉCURITÉ
GROUP SAFETY PUBLICATION
Sécurité des transformateurs,
blocs d'alimentation et dispositifs analogues –
Partie 2-20:
Règles particulières pour les petites bobines
d'inductance
Safety of power transformers,
power supply units and similar devices –
Part 2-20:
Particular requirements for small reactors
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utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
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For price, see current catalogue

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61558-2-20  IEC:2000 – 3 –
CONTENTS
Page
FOREWORD . 5
Clause
1 Scope . 9
2 Normative references . 11
3 Definitions. 11
4 General requirements. 15
5 General notes on tests . 15
6 Ratings . 15
7 Classification .15
8 Marking and other information . 17
9 Protection against accessibility to hazardous live parts . 19
10 Change of input voltage setting . 19
11 Output voltage and output current under load . 21
12 No-load output voltage . 21
13 Short-circuit voltage . 21
14 Heating . 21
15 Short-circuit and overload protection . 23
16 Mechanical strength . 25
17 Protection against harmful ingress of dust, solid objects and moisture . 25
18 Insulation resistance and dielectric strength. 27
19 Construction. 27
20 Components. 27
21 Internal wiring . 29
22 Supply connection and other external flexible cords . 29
23 Terminals for external conductors. 29
24 Provision for protective earthing . 29
25 Screws and connections. 29
26 Creepage distances, clearances and distances through insulation . 29
27 Resistance to heat, abnormal heat, fire and tracking. 29
28 Resistance to rusting. 29
Annexes . 31

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61558-2-20  IEC:2000 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
SAFETY OF POWER TRANSFORMERS,
POWER SUPPLY UNITS AND SIMILAR DEVICES –
Part 2-20: Particular requirements for small reactors
FOREWORD
1) The IEC (International Electrotechnical Commission) is a world-wide organisation for standardisation comprising all
national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The IEC
collaborates closely with the International Organisation for Standardisation (ISO) in accordance with conditions
determined by agreement between the two organisations.
2) The formal decisions or agreements of the 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
National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form of
standards, technical specifications, technical reports or guides and they are accepted by the National Committees in
that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International Standards
transparently to the maximum extent possible in their national and regional standards. Any divergence between the
IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patents rights. The IEC shall not be held responsible for identifying any or all such patents rights.
International standard IEC 61558-2-20 has been prepared by technical committee 96: Small
power transformers, reactors and power supply units: safety requirements.
It has the status of a group safety publication in accordance with IEC Guide 104: Guide for the
drafting of safety standards, and the role of committees with safety pilot functions and safety
group functions (1984).
The text of this standard is based on the following documents:
FDIS Report on voting
96/146/FDIS 96/149/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 3.
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.

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61558-2-20  IEC:2000 – 7 –
This part 2-20 is intended to be used in conjunction with IEC 61558-1. It was established on the
basis of the first edition (1997) of that standard.
This part 2-20 supplements or modifies the corresponding clauses in IEC 61558-1, so as to
convert that publication into the IEC standard: Particular requirements for small reactors.
When a particular subclause of part 1 is not mentioned in this part 2-20, that subclause applies
as far as is reasonable. Where this standard states "addition", "modification" or "replacement",
the relevant text of part 1 is to be adapted accordingly.
In this standard, 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 the standard the words in bold are defined in clause 3.
Subclauses which are 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
2004-12. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

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61558-2-20  IEC:2000 – 9 –
SAFETY OF POWER TRANSFORMERS,
POWER SUPPLY UNITS AND SIMILAR DEVICES –
Part 2-20: Particular requirements for small reactors
1 Scope
Replacement:
This part of IEC 61558 applies to stationary or portable, single-phase or poly-phase, air-cooled
(natural or forced) general purpose small reactors, including alternating current,
premagnetised and current compensated reactors, independent or associated, having a rated
supply voltage not exceeding 1 000 V a.c. or d.c. and rated frequency not exceeding 1 MHz,
the rated power not exceeding
– 2 kVAR a.c. (2 kW d.c.) for single-phase reactors;
– 10 kVAR a.c. (10 kW d.c.) for poly-phase reactors.
This standard is also applicable to small reactors without limitation of the rated power;
however, such small reactors are considered as special reactors and are subjected to an
agreement between the purchaser and the supplier.
This standard is applicable to dry-type small reactors. The windings may be encapsulated or
non-encapsulated.
This standard does not apply to
– reactors covered by IEC 60289;
– ballast for tubular fluorescent lamps covered by IEC 60920;
– ballast for discharge lamps (excluding tubular fluorescent lamps) covered by IEC 60922.
NOTE 1 For small reactors filled with liquid dielectric or pulverised material such as sand, additional requirements
are under consideration.
NOTE 2 In locations where special environmental conditions prevail, particular requirements may be necessary.
NOTE 3 Normally, small reactors are intended to be associated with equipment for functional requirements of the
equipment or requirements by the installation rules or by other appliance specifications.
NOTE 4 Small reactors incorporating electronic circuits and components are also covered by this standard.
NOTE 5 The safety insulation may be provided (or completed) by other parts or features of the equipment, such as
the body.
NOTE 6 Small reactors for particular applications will in the future be covered by complementary normative
annexes.

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61558-2-20  IEC:2000 – 11 –
2 Normative references
This clause of part 1 is applicable.
3 Definitions
This clause of part 1 is applicable except as follows:
Modification:
Where part 1 is applicable, the word "transformer", if used, shall be replaced by "reactor".
Addition:
3.1.101
reactor
arrangement comprising one or more windings with an impedance depending on the frequency,
working in accordance with the principle of self-induction whereby a magnetising current
generates a magnetic field through a magnetically effective core or through air
NOTE Reactors with toroïdal core are also included in this definition.
3.1.102
alternating current reactor
reactor in which the magnetising current generates an alternating magnetic field, changing its
polarity depending on the frequency
3.1.103
premagnetised reactor
reactor in which the magnetising direct current generates a magnetic field of only one polarity,
while a superimposed alternating current alters the direct magnetic field depending on its
strength and the frequency
3.1.104
current compensated reactor
reactor with at least two windings on a common core, where the magnetising currents are in
opposite directions in order to reduce the magnetic flux
3.1.105
overload proof reactor
in which the temperature does not exceed the specified limits when the is
reactor reactor
overloaded and which continues to meet all requirements of this standard after the removal of
the overload
3.1.105.1
non-inherently overload proof reactor
overload proof reactor equipped with a protective device which opens the circuit, or reduces
the current in the circuit when the reactor is overloaded, and which continues to meet all
requirements of this standard after the removal of the overload and resetting or replacing of the
protective device
NOTE 1 Examples of protective devices are fuses, overload releases, thermal fuses, thermal links, thermal cut-
outs, PTC resistors and automatic circuit-breakers.
NOTE 2 In case of protection by a device which cannot be replaced nor re-set, the wording "continues to meet all
requirements of this standard after removal of the overload" does not imply that the reactor continues to operate.

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61558-2-20  IEC:2000 – 13 –
3.1.105.2
inherently overload proof reactor
overload proof reactor not equipped with a device to protect the reactor and in which the
temperature in the case of overload, by construction, does not exceed the specified limits and
which continues to operate and meet all the requirements of this standard after the removal of
the overload
3.1.106
non-overload proof reactor
reactor which is intended to be protected against excessive temperature by means of a
protective device not provided with the reactor and which continues to meet all the
requirements of this standard after the removal of the overload and resetting or replacing of the
protective device
3.1.107
fail-safe reactor
reactor which, after abnormal use, permanently fails to function by an interruption of the failing
circuit but presents no danger
...