Safety of power transformers, power supplies, reactors and similar products -- Part 2-2: Particular requirements and tests for control transformers and power supplies incorporating control transformers

This part of IEC 61558 deals with safety aspects of control transformers and power supplies incorporating control transformers such as electrical, thermal and mechanical safety. This Part 2-2 is applicable to control transformers and power supplies incorporating both control transformers and electronic circuits. This Part 2-2 is not applicable to external circuits and their components intended to be connected to the input terminals, output terminals or socket-outlets of the transformer and power supplies. This Part 2-2 does not apply to transformers covered by IEC 60076-11. This Part 2-2 applies to stationary or portable, single-phase or poly-phase, air-cooled (natural or forced), independent or associated control transformers and power supplies incorporating a control transformer, having a rated supply voltage not exceeding 1 000 V a.c. and rated supply and internal operating frequency not exceeding 500 Hz. The rated thermal output does not exceed: - 25 kVA for single-phase control transformers and power supplies incorporating control transformers; - 40 kVA for poly-phase control transformers and power supplies incorporating control transformers. This Part 2-2 is applicable to control transformers and power supplies incorporating control transformers without limitation of the rated output subject to an agreement between the purchaser and the manufacturer. This Part 2-2 is applicable to dry-type transformers. The windings may be encapsulated or non-encapsulated. 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 control transformers and independent power supplies incorporating control transformers, the no-load output voltage and / or the rated output voltage is not less than 50 V a.c., or 120 V ripple free d.c.

Sicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-2: Besondere Anforderungen und Prüfungen an Steuertransformatoren und Netzgeräten, die Steuertransformatoren enthalten

Sécurité des transformateurs, alimentations, bobines d'inductance et produits analogues -- Partie 2-2: Règles particulières et essais pour les transformateurs de commande et les alimentations incorporant les transformateurs de commande

La présente partie de la CEI 61558 traite des aspects relatifs à la sécurité des transformateurs de commande et des alimentations incorporant des transformateurs de commande tels que les aspects de sécurité électrique, thermique et mécanique Cette deuxième édition annule et remplace la première édition publiée en 1997. Elle constitue une révision technique. Les principales modifications consistent en la mise à jour de cette Partie 2-2 conformément à la Partie 1 édition 2, et en l'ajout des alimentations dans le domaine d'application. Cette Partie 2-2 a le statut de publication groupée de sécurité conformément au guide CEI 104.

Varnost močnostnih transformatorjev, napajalnikov, reaktorjev in podobnih izdelkov - 2-2. del: Posebne zahteve za kontrolne transformatorje in napajalnike s kontrolnimi transformatorji (IEC 61558-2-2:2007)

General Information

Status
Published
Publication Date
04-Nov-2007
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
24-Oct-2007
Due Date
29-Dec-2007
Completion Date
05-Nov-2007

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Safety of power transformers, power supplies, reactors and similar products - Part 2-2: Particular requirements and tests for control transformers and power supplies incorporating control transformersSRGREQLKSécurité des transformateurs, alimentations, bobines d'inductance et produits analogues - Partie 2-2: Regles particulieres et essais pour les transformateurs de commande et les alimentations incorporant les transformateurs de commandeSicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-2: Besondere Anforderungen und Prüfungen an Steuertransformatoren und Netzgeräten, die Steuertransformatoren enthaltenTa slovenski standard je istoveten z:EN 61558-2-2:2007SIST EN 61558-2-2:2007en,fr,de29.180Transformatorji. DušilkeTransformers. ReactorsICS:SIST EN 61558-2-2:19991DGRPHãþDSLOVENSKI
STANDARDSIST EN 61558-2-2:200701-december-2007







EUROPEAN STANDARD EN 61558-2-2 NORME EUROPÉENNE
EUROPÄISCHE NORM March 2007
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61558-2-2:2007 E
ICS 29.180 Supersedes EN 61558-2-2:1998
English version
Safety of power transformers, power supplies,
reactors and similar products -
Part 2-2: Particular requirements and tests for control transformers
and power supplies incorporating control transformers (IEC 61558-2-2:2007)
Sécurité des transformateurs, alimentations, bobines d'inductance
et produits analogues -
Partie 2-2: Règles particulières
et essais pour les transformateurs
de commande et les alimentations incorporant les transformateurs
de commande (CEI 61558-2-2:2007)
Sicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-2: Besondere Anforderungen
und Prüfungen an Steuertransformatoren und Netzgeräten,
die Steuertransformatoren enthalten (IEC 61558-2-2:2007)
This European Standard was approved by CENELEC on 2007-02-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.



EN 61558-2-2:2007
- 2 - Foreword The text of document 96/253/FDIS, future edition 2 of IEC 61558-2-2, prepared by IEC TC 96, Small power transformers, reactors, power supply units and similar products, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61558-2-2 on 2007-02-01. This European Standard supersedes EN 61558-2-2:1998 + corrigendum February 1998. The main changes consist of updating this Part 2-2 in accordance with EN 61558-1:2005, and adding power supplies to the scope. This Part 2-2 is intended to be used in conjunction with the latest edition of EN 61558-1 and its amendments. It is based on EN 61558-1:2005. This Part 2-2 supplements or modifies the corresponding clauses in EN 61558-1, so as to convert that publication into the European standard: Particular requirements and tests for control transformers and power supplies incorporating control transformers. Where a particular subclause of Part 1 is not mentioned in this Part 2-2, that subclause applies as far as is reasonable. Where this Part 2-2 states "addition", "modification" or "replacement", the relevant text of Part 1 is to be adapted accordingly. The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop)
2007-11-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow)
2010-02-01 In this Part 2-2, 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 2-2, the words in bold are defined in Clause 3. Subclauses additional to those in Part 1 are numbered starting from 101; supplementary annexes are entitled AA, BB, etc. Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 61558-2-2:2007 was approved by CENELEC as a European Standard without any modification. __________



- 3 - EN 61558-2-2:2007
Annex ZA (normative)
Normative references to international publications with their corresponding European publications
Addition: Publication Year Title EN/HD Year IEC 60076-11 - 1) Power transformers -
Part 11: Dry-type transformers EN 60076-11 2004 2)
1) Undated reference.
2) Valid edition at date of issue.







NORME INTERNATIONALE CEIIEC INTERNATIONAL STANDARD 61558-2-2Deuxième éditionSecond edition2007-01 Sécurité des transformateurs, alimentations, bobines d'inductance et produits analogues – Partie 2-2: Règles particulières et essais
pour les transformateurs de commande
et les alimentations incorporant
les transformateurs de commande
Safety of power transformers, power supplies, reactors and similar products – Part 2-2: Particular requirements and tests for
control transformers and power supplies incorporating control transformers
Pour prix, voir catalogue en vigueur For price, see current catalogue© IEC 2007
Droits de reproduction réservés

Copyright - all rights reserved Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photo-copie et les microfilms, sans l'accord écrit de l'éditeur. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission,
3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, SwitzerlandTelephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch
Web: www.iec.ch Commission Electrotechnique InternationaleInternational Electrotechnical CommissionN CODE PRIX PRICE CODE PUBLICATION GROUPÉE DE SÉCURITÉ
GROUP SAFETY PUBLICATION



61558-2-2 © IEC:2007 – 3 –
CONTENTS FOREWORD.5
1 Scope.9 2 Normative references.11 3 Terms and definitions.11 4 General requirements.13 5 General notes on tests.13 6 Ratings.13 7 Classification.15 8 Marking and other information.15 9 Protection against electric shock.17 10 Change of input voltage setting.17 11 Output voltage and output current under load.17 12 No-load output voltage.19 13 Short-circuit voltage.19 14 Heating.19 15 Short-circuit and overload protection.21 16 Mechanical strength.21 17 Protection against harmful ingress of dust, solid objects and moisture.21 18 Insulation resistance, dielectric strength and leakage current.21 19 Construction.21 20 Components.23 21 Internal wiring.23 22 Supply connection and other external flexible cables or cords.23 23 Terminals for external conductors.25 24 Provisions for protective earthing.25 25 Screws and connections.25 26 Creepage distances, clearances and distances through insulation.25 27 Resistance to heat, fire and tracking.25 28 Resistance to rusting.25
Annexes.27



61558-2-2 © IEC:2007 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ___________
SAFETY OF POWER TRANSFORMERS, POWER SUPPLIES,
REACTORS AND SIMILAR PRODUCTS –
Part 2-2: Particular requirements and tests
for control transformers and power supplies
incorporating control 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-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by 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 interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
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 61558-2-1 has been prepared by IEC technical committee 96: Small power transformers, reactors, power supply units and similar products. This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this Part 2-2 in accordance with Part 1, edition 2, and adding power supplies to the scope. This Part 2-2 has the status of a group safety publication in accordance with IEC Guide 104: The preparation of safety publications and the use of basic safety publications and group safety publications (1997).



61558-2-2 © IEC:2007 – 7 –
The text of this standard is based on the following documents: FDIS Report on voting 96/253/FDIS 96/266/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 2-2 is intended to be used in conjunction with the last edition of IEC 61558-1 and its amendments. It is based on the second edition (2005) of that standard. This Part 2-2 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 control transformers and power supplies incorporating control transformers. A list of all parts of the IEC 61558 series, under the general title: Safety of power transformers, power supplies, reactors and similar products, can be found on the IEC website. Where a particular subclause of Part 1 is not mentioned in this Part 2-2, that subclause applies as far as is reasonable. Where this Part 2-2 states "addition", "modification" or "replacement", the relevant text of Part 1 is to be adapted accordingly. In this Part 2-2, the following print types are used: – requirements proper: in roman type; – test specifications: in italic type; – explanatory matter: in
...

SLOVENSKI oSIST prEN 61558-2-2:2005

PREDSTANDARD
julij 2005
Varnost močnostnih transformatorjev, napajalnikov, reaktorjev in podobnih
izdelkov – 2-2. del: Posebne zahteve za kontrolne transformatorje in
napajalnike s kontrolnimi transformatorji
Safety of power transformers, power supplies, reactors and similar products – Part
2-2: Particular requirements for control transformers and power supplies
incorporating control transformers
ICS 29.180 Referenčna številka
oSIST prEN 61558-2-2:2005(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------
96/223/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJET DE COMITÉ POUR VOTE (CDV)
Project number IEC 61558-2-2 Ed.2
Numéro de projet

IEC/TC or SC: Date of circulation
TC 96
Closing date for voting (Voting
Date de diffusion 2005-05-13
CEI/CE ou SC: mandatory for P-members)

Date de clôture du vote (Vote

obligatoire pour les membres (P))
2005-10-14
Titre du CE/SC:    TC/SC Title: Safety of power transformers, power
supplies, reactors and similar products
Secretary: Wolfgang Reichelt /DE
Secrétaire:
Also of interest to the following committees Supersedes document
Intéresse également les comités suivants Remplace le document
   96/222/MCR
Functions concerned
Fonctions concernées
Safety EMC Environment Quality assurance
Sécurité
CEM Environnement Assurance qualité
CE DOCUMENT EST TOUJOURS À L'ÉTUDE ET SUSCEPTIBLE DE THIS DOCUMENT IS STILL UNDER STUDY AND SUBJECT TO CHANGE. IT
MODIFICATION. IL NE PEUT SERVIR DE RÉFÉRENCE. SHOULD NOT BE USED FOR REFERENCE PURPOSES.
LES RÉCIPIENDAIRES DU PRÉSENT DOCUMENT SONT INVITÉS À RECIPIENTS OF THIS DOCUMENT ARE INVITED TO SUBMIT, WITH THEIR
PRÉSENTER, AVEC LEURS OBSERVATIONS, LA NOTIFICATION DES COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF
DROITS DE PROPRIÉTÉ DONT ILS AURAIENT ÉVENTUELLEMENT WHICH THEY ARE AWARE AND TO PROVIDE SUPPORTING
CONNAISSANCE ET À FOURNIR UNE DOCUMENTATION EXPLICATIVE. DOCUMENTATION.

Titre :    Title : IEC 61558-2-2 Ed.2 SAFETY OF POWER
TRANSFORMERS, POWER SUPPLIES,

REACTORS AND SIMILAR PRODUCTS
Part 2-2: Particular requirements for control
transformers and power supplies incorporating
control transformers:


Note d'introduction Introductory note
This part 2-2 of IEC 61558 applies to stationary

or portable, single-phase or poly-phases, air-
cooled (natural or forced), independent or
associated control transformers and power
supplies incorporating control transformer,
having a rated supply voltage not exceeding
1000 V a.c. and rated supply and internal
operating frequency not exceeding 500 Hz.
ATTENTION ATTENTION

CDV soumis en parallèle au vote (CEI) Parallel IEC CDV/CENELEC Enquiry
et à l’enquête (CENELEC)

Copyright © 2005 International Electrotechnical Commission, IEC. All rights reserved. It is

permitted to download this electronic file, to make a copy and to print out the content for the sole
purpose of preparing National Committee positions. You may not copy or "mirror" the file or
printed version of the document, or any part of it, for any other purpose without permission in
writing from IEC.
FORM CDV (IEC) 2002-08-09

---------------------- Page: 2 ----------------------
61558-2-2 Ed. 2/CDV © IEC – 2 –


INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________

SAFETY OF POWER TRANSFORMERS, POWER SUPPLIES,
REACTORS AND SIMILAR PRODUCTS
Part 2-2: Particular requirements for control transformers and power
supplies incorporating control 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-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
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
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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.

This International standard IEC 61558-2-2 has been prepared by technical committee 96: Small
power transformers, reactors and power supply units and similar products.

It has the status of a group safety publication in accordance with IEC Guide 104.

The text of this standard is based on the following documents:



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.

---------------------- Page: 3 ----------------------
61558-2-2 Ed. 2/CDV © IEC – 3 –


This part 2 is intended to be used in conjunction with the latest Edition of IEC 60558-1 and its
amendments. It is based on the second edition of that standard.
This part 2 supplements or modifies the corresponding clauses in IEC 61558-1, so as to
convert that publication into the IEC standard “Particular requirements for control transformers
and power supplies incorporating control transformers”

This standard replaces Edition 1

Where a specific subclause of part 1 is not mentioned in this part 2, 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 the
)
1
maintenance result 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.





)
1
The National Committees are requested to note that for this publication the maintenance result date is
.2009.

---------------------- Page: 4 ----------------------
61558-2-2 Ed. 2/CDV © IEC – 4 –


SAFETY OF POWER TRANSFORMERS, POWER SUPPLIES,
REACTORS AND SIMILAR PRODUCTS
Part 2-2: Particular requirements for control transformers and power
supplies incorporating control transformers

1 Scope
Replacement:
This International standard deals with safety aspects such as electrical, thermal and
mechanical safety of control transformers and power supplies incorporating control
transformers.
This standard is applicable to transformers and power supplies incorporating electronic circuits.
This standard is not applicable to external circuits and their components intended to be
connected to the input and output terminals or socket- outlets of the transformer and power
supplies
This part 2-2 of IEC 61558 applies to stationary or portable, single-phase or poly-phases, air-
cooled (natural or forced), independent or associated control transformers and power
supplies incorporating control transformer, having a rated supply voltage not exceeding 1
000 V a.c. and rated supply and internal operating frequency not exceeding 500 Hz.
The rated output does not exceed:

-25 kVA for single-phase control transformers; and power supplies incorporating
control transformer
-40 kVA for poly-phase control transformers; and power supplies incorporating control
transformer
This standard is also applicable to control transformers and power supplies incorporating
control transformer without limitation of the rated output subject to an agreement between
the purchaser and the supplier.
This standard is applicable to dry-type transformers. The windings may be encapsulated or
non-encapsulated.
The no-load output voltage and the rated output voltage do not exceed 1 000 V a.c. or
1 415 V ripple free d.c.
For independent control transformers the no-load output voltage is not less than 50 V a.c.,
Small power transformers, reactors, power suppl units and similar products and for
independent power supplies incorporating control transformer the no load output voltage not
less than 50 V a.c or 120 V ripple free d.c.
Transformers covered by this standard are used only in applications where double or
reinforced insulation between circuits is not required by the installation rules or by the
appliance specification.
NOTE 1 – Normally, the transformers are intended to be associated with the equipment to provide voltages
different from the supply voltage for the functional requirement of the equipment. T
...

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