Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - AC semiconductor motor controllers and starters (IEC 60947-4-2:2011)

IEC 60947-4-2:2011 applies to a.c. semiconductor motor controllers and starters, which may include a series mechanical switching device, intended to be connected to circuits, the rated voltage of which does not exceed  1 000 V a.c. This standard characterizes a.c. semiconductor motor controllers and starters with and without bypass means. This third edition replaces the second edition published in 1999 and its Amendments 1 (2001) and 2 (2006). It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition and its amendments:  - updated EMC normative references and associated requirements,  - new references to IEC 60947-1,  - marking of electronic relays without thermal memory,  - marking of tripping time at 0 °C ambient or below,  - new test requirements for limits of operation of time-delay overload relays,  - new classes of overload current withstand time,  - damp heat, salt mist, vibration and shock tests,  - short-circuit test in the smallest enclosure,  - update of the routine and sampling tests.   This publication is to be read in conjunction with IEC 60947-1:2007.

Niederspannungsschaltgeräte - Teil 4-2: Schütze und Motorstarter - Halbleiter-Motor-Steuergeräte und -Starter für Wechselspannungen (IEC 60947-4-2:2011)

Appareillage à basse tension - Partie 4-2: Contacteurs et démarreurs de moteurs - Gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif (CEI 60947-4-2:2011)

La CEI 60947-4-2:2011 est applicable aux gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif, qui peuvent comprendre en série des appareils mécaniques de connexion, destinés à être reliés à des circuits dont la tension assignée ne dépasse pas 1 000 V en courant alternatif. La présente norme définit les caractéristiques des gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif, avec ou sans dispositif de court-circuitage. Cette troisième édition annule et remplace la deuxième édition parue en 1999 et ses Amendements 1 (2001) et 2 (2006). Elle constitue une révision technique. La présente édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente et ses amendements:  - références normatives CEM mises à jour et leurs exigences associées,  - nouvelles références à la CEI 60947-1,  - marquage des relais électroniques sans mémoire thermique,  - marquage de la durée de déclenchement à une température ambiante inférieure ou égale à 0 °C,  - nouvelles exigences d'essai concernant les limites de fonctionnement des relais de surchage temporisés,  - nouvelles classes de durée de tenue au courant de surcharge,  - essais de chaleur humide, brouillard salin, vibrations et chocs,  - essai de court-circuit dans l'enveloppe la plus petite,  - mise à jour des essais individuels et d'échantillonnage.   Cette publication doit être lue conjointement avec la CEI 60947-1:2007.

Nizkonapetostne stikalne in krmilne naprave - 4-2. del: Kontaktorji in motorski zaganjalniki - Polprevodniški krmilniki in zaganjalniki motorjev na izmenični tok (IEC 60947-4-2:2011)

Ta standard se uporablja za polprevodniške krmilnike in zaganjalnike motorjev na izmenični tok, ki lahko vključujejo serijsko mehansko stikalno napravo, namenjeno priključku na tokokroge z nazivno izmenično napetostjo, ki ne presega 1000 V. Ta standard opisuje polprevodniške krmilnike in zaganjalnike motorjev na izmenični tok z možnostjo obvoda in brez nje. Polprevodniški krmilniki in zaganjalniki motorjev na izmenični tok, obravnavani v tem standardu, običajno niso namenjeni prekinitvi kratkostičnih tokov. Zato naj bi bila ustrezna zaščita pred kratkim stikom (glej točko 8.2.5) del inštalacije, vendar ne nujno tudi del polprevodniškega krmilnika ali zaganjalnika motorjev na izmenični tok. V tem okviru ta standard določa zahteve za polprevodniške krmilnike in zaganjalnike motorjev na izmenični tok, povezane z ločenimi napravami za zaščito pred kratkim stikom. Ta standard se ne uporablja za: – stalno delovanje motorjev na izmenični tok pri hitrostih motorjev, ki niso običajne; – polprevodniško opremo, vključno s polprevodniškimi kontaktorji (glej točko 2.2.13 standarda IEC 60947-1:2007), ki krmilijo nemotorske obremenitve; – elektronske krmilnike moči na izmenični tok, ki so zajeti v skupini standardov IEC 60146. Kontaktorji, releji za preobremenitev in naprave s krmilnimi tokokrogi, ki se uporabljajo pri polprevodniških krmilnikih in zaganjalnikih motorjev na izmenični tok, morajo izpolnjevati zahteve ustreznega standarda za proizvod. Kadar se uporabljajo mehanske stikalne naprave, morajo izpolnjevati zahteve svojega standarda za proizvod IEC in dodatne zahteve tega standarda, Cilj tega standarda je navesti: – značilnosti polprevodniških krmilnikov in zaganjalnikov motorjev na izmenični tok ter povezane opreme; – pogoje, ki jih polprevodniški krmilniki in zaganjalniki motorjev na izmenični tok izpolnjujejo v zvezi z a) njihovim delovanjem in vedenjem, b) njihovimi dielektričnimi lastnostmi, c) stopnjami zaščite, ki jo zagotavljajo njihova ohišja, kadar je to primerno, d) njihovo izvedbo; – preskuse za potrditev izpolnjevanja teh pogojev in metode, ki bodo sprejete v zvezi s temi preskusi; – informacije, ki se predložijo opremi ali navedejo v navodilih proizvajalca.

General Information

Status
Published
Publication Date
16-Jul-2012
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
23-Aug-2021
Due Date
15-Sep-2021

Relations

Standard
SIST EN 60947-4-2:2012
English language
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SLOVENSKI STANDARD
01-september-2012
1DGRPHãþD
SIST EN 60947-4-2:2000
SIST EN 60947-4-2:2000/A1:2002
SIST EN 60947-4-2:2000/A2:2007
1L]NRQDSHWRVWQHVWLNDOQHLQNUPLOQHQDSUDYHGHO.RQWDNWRUMLLQPRWRUVNL
]DJDQMDOQLNL3ROSUHYRGQLãNLNUPLOQLNLLQ]DJDQMDOQLNLPRWRUMHYQDL]PHQLþQLWRN
,(&
Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - AC
semiconductor motor controllers and starters (IEC 60947-4-2:2011)
Niederspannungsschaltgeräte - Teil 4-2: Schütze und Motorstarter - Halbleiter-Motor-
Steuergeräte und -Starter für Wechselspannungen (IEC 60947-4-2:2011)
Appareillage à basse tension - Partie 4-2: Contacteurs et démarreurs de moteurs -
Gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif (CEI 60947
-4-2:2011)
Ta slovenski standard je istoveten z: EN 60947-4-2:2012
ICS:
29.130.20 Nizkonapetostne stikalne in Low voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 60947-4-2
NORME EUROPÉENNE
June 2012
EUROPÄISCHE NORM
ICS 29.130.20 Supersedes EN 60947-4-2:2000 + A1:2002 + A2:2006

English version
Low-voltage switchgear and controlgear -
Part 4-2: Contactors and motor-starters -
AC semiconductor motor controllers and starters
(IEC 60947-4-2:2011)
Appareillage à basse tension -  Niederspannungsschaltgeräte -
Partie 4-2: Contacteurs et démarreurs de Teil 4-2: Schütze und Motorstarter -
moteurs - Halbleiter-Motor-Steuergeräte und -Starter
Gradateurs et démarreurs à für Wechselspannungen
semiconducteurs de moteurs à courant (IEC 60947-4-2:2011)
alternatif
(CEI 60947-4-2:2011)
This European Standard was approved by CENELEC on 2011-06-22. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, 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, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60947-4-2:2012 E
Foreword
The text of document (17B/1734/FDIS), future edition 3 of IEC 60947-4-2, prepared by SC 17B, "Low-
voltage switchgear and controlgear", of IEC TC 17, "Switchgear and controlgear", was submitted to the
IEC-CENELEC parallel vote and approved by CENELEC as EN 60947-4-2:2012.
The following dates are fixed:
• latest date by which the document has
(dop) 2012-12-29
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national
(dow) 2014-06-22
standards conflicting with the

document have to be withdrawn
This European Standard supersedes EN 60947-4-2:2000 + A1:2002 + A2:2006.
EN 60947-4-2:2000 + A1:2002 + A2:2006:
• updated EMC normative references and associated requirements,
• new references to EN 60947-1,
• marking of electronic relays without thermal memory,
• marking of tripping time at 0 °C ambient or below,
• new test requirements for limits of operation of time-delay overload relays,
• new classes of overload current withstand time,
• damp heat, salt mist, vibration and shock tests,
• short-circuit test in the smallest enclosure,
• update of the routine and sampling tests.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
This standard shall be read in conjunction with EN 60947-1:2007, Low-voltage switchgear and
controlgear – Part 1: General rules. The provisions of the general rules are applicable to this standard,
where specifically called for.
This standard covers the Principle Elements of the Safety Objectives for Electrical Equipment Designed
for Use within Certain Voltage Limits (LVD - 2006/95/EC).

This document has been prepared under a mandate given to CENELEC by the European Commission
and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this
document.
__________
- 3 - EN 60947-4-2:2012
Endorsement notice
The text of the International Standard IEC 60947-4-2:2011 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60146 series NOTE  Harmonized in EN 60146 series (not modified).
IEC 60255 series NOTE  Harmonized in EN 60255 series (partially modified).
IEC 60947-5 series NOTE  Harmonized in EN 60947-5 series (partially modified).
IEC 61000-3-2:2005 NOTE  Harmonized as EN 61000-3-2:2006 + A1:2009 + A2:2009 (not modified).
+ A1: 2008
+ A2: 2009
IEC 61000-4-2:2008
NOTE  Harmonized as EN 61000-4-2:2009 (not modified).
IEC 61000-4-3:2006
NOTE  Harmonized as EN 61000-4-3:2006 + A1:2008 + A2:2010 (not modified).
+ A1: 2007
+ A2: 2010
IEC 61000-4-4:2004
NOTE  Harmonized as EN 61000-4-4:2004 + A1:2010 (not modified).
+ A1: 2010
IEC 61000-4-5:2005
NOTE  Harmonized as EN 61000-4-5:2006 (not modified).
IEC 61000-4-6:2008
NOTE  Harmonized as EN 61000-4-6:2009 (not modified).
IEC 61000-4-11:2004
NOTE  Harmonized as EN 61000-4-11:2004 (not modified).
IEC 61131-2:2007
NOTE  Harmonized as EN 61131-2:2007 (not modified).
__________
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60034-1 (mod) 2010 Rotating electrical machines - EN 60034-1 2010
Part 1: Rating and performance + corr. October 2010

IEC 60085 2007 Electrical insulation - Thermal evaluation and EN 60085 2008
designation
IEC 60269-1 2006 Low-voltage fuses - EN 60269-1 2007
+ A1 2009 Part 1: General requirements + A1 2009

IEC 60410 1973 Sampling plans and procedures for inspection - -
by attributes
IEC 60664 Series Insulation coordination for equipment within EN 60664 Series
low-voltage systems
IEC 60947-1 2007 Low-voltage switchgear and controlgear - EN 60947-1 2007
Part 1: General rules
IEC 61000-4 Series Electromagnetic compatibility (EMC) - EN 61000-4 Series
Part 4: Testing and measurement techniques -

CISPR 11 (mod) 2009 Industrial, scientific and medical equipment - EN 55011 2009
+ A1 2010 Radio-frequency disturbance characteristics - + A1 2010
Limits and methods of measurement

- 5 - EN 60947-4-2:2012
Annex ZZ
(informative)
Coverage of Essential Requirements of EU Directives

This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers all
relevant essential requirements as given in Article 1 of Annex I of the Directive 2004/108/EC.
Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive concerned.
WARNING - Other requirements and other EU Directives may be applicable to the products falling within
the scope of this standard.
IEC 60947-4-2 ®
Edition 3.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –
Part 4-2: Contactors and motor-starters – AC semiconductor motor controllers
and starters
Appareillage à basse tension –
Partie 4-2: Contacteurs et démarreurs de moteurs – Gradateurs et démarreurs à
semiconducteurs de moteurs à courant alternatif

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XD
ICS 29.130.20 ISBN 978-2-88912-505-0

– 2 – 60947-4-2 © IEC:2011
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms, definitions, symbols and abbreviations . 10
3.1 General . 10
3.2 Alphabetical index of terms . 10
3.3 Terms and definitions concerning a.c. semiconductor motor controllers and
starters . 12
3.4 Terms and definitions concerning hybrid motor controllers and starters . 14
3.5 Terms and definitions concerning EMC definitions . 18
3.6 Symbols and abbreviations . 19
4 Classification . 19
5 Characteristics of a.c. semiconductor motor controllers and starters . 20
5.1 Summary of characteristics . 20
5.2 Type of equipment . 20
5.2.1 Form of equipment . 20
5.2.2 Number of poles . 20
5.2.3 Kind of current . 20
5.2.4 Interrupting medium (air, vacuum, etc.) . 20
5.2.5 Operating conditions of the equipment . 20
5.3 Rated and limiting values for main circuits . 21
5.3.1 Rated voltages . 21
5.3.2 Currents . 23
5.3.3 Rated frequency . 23
5.3.4 Rated duty . 23
5.3.5 Normal load and overload characteristics . 24
5.3.6 Rated conditional short-circuit current . 25
5.4 Utilization category . 25
5.4.1 General . 25
5.4.2 Assignment of ratings based on the results of tests . 26
5.5 Control circuits . 27
5.6 Auxiliary circuits . 27
5.7 Characteristics of relays and releases (overload relays) . 27
5.7.1 Summary of characteristics. 28
5.7.2 Types of relay or release . 28
5.7.3 Characteristic values . 28
5.7.4 Designation and current settings of overload relays . 29
5.7.5 Time-current characteristics of overload relays . 29
5.7.6 Influence of ambient air temperature . 30
5.8 Co-ordination with short-circuit protective devices (SCPD) . 30
6 Product information . 30
6.1 Nature of information . 30
6.2 Marking . 31
6.3 Instructions for installation, operation, and maintenance . 31
7 Normal service, mounting and transport conditions . 32

60947-4-2 © IEC:2011 – 3 –
7.1 Normal service conditions . 32
7.1.1 Ambient air temperature . 32
7.1.2 Altitude . 32
7.1.3 Atmospheric conditions . 32
7.1.4 Shock and vibrations . 32
7.2 Conditions during transport and storage . 32
7.3 Mounting . 32
7.4 Electrical system disturbances and influences . 32
8 Constructional and performance requirements . 33
8.1 Constructional requirements . 33
8.1.1 General . 33
8.1.2 Materials . 33
8.1.3 Current-carrying parts and their connections . 33
8.1.4 Clearances and creepage distances . 33
8.1.5 Actuator . 33
8.1.6 Indication of the contact position . 33
8.1.7 Additional requirements for equipment suitable for isolation . 33
8.1.8 Terminals . 33
8.1.9 Additional requirements for equipment provided with a neutral pole . 34
8.1.10 Provisions for protective earthing . 34
8.1.11 Enclosures for equipment . 34
8.1.12 Degrees of protection of enclosed equipment . 34
8.1.13 Conduit pull-out, torque and bending with metallic conduits . 34
8.2 Performance requirements . 34
8.2.1 Operating conditions . 34
8.2.2 Temperature rise . 38
8.2.3 Dielectric properties. 41
8.2.4 Normal load and overload performance requirements . 42
8.2.5 Co-ordination with short-circuit protective devices . 47
8.3 EMC requirements . 47
8.3.1 General . 47
8.3.2 Emission . 48
8.3.3 Immunity . 48
9 Tests . 50
9.1 Kinds of tests . 50
9.1.1 General . 50
9.1.2 Type tests . 50
9.1.3 Routine tests . 50
9.1.4 Sampling tests . 50
9.1.5 Special tests . 51
9.2 Compliance with constructional requirements . 51
9.3 Compliance with performance requirements . 51
9.3.1 Test sequences . 51
9.3.2 General test conditions . 52
9.3.3 Performance under no load, normal load, and overload conditions . 52
9.3.4 Performance under short-circuit conditions . 62
9.3.5 EMC tests . 65
9.3.6 Routine and sampling tests . 68
Annex A (normative) Marking and identification of terminals . 70

– 4 – 60947-4-2 © IEC:2011
Annex B Vacant . 73
Annex C (normative) Co-ordination at the crossover current between the starter and
associated SCPD . 74
Annex D Vacant . 78
Annex E Vacant . 79
Annex F (informative) Operating capability. 80
Annex G (informative) Examples of control circuit configurations . 83
Annex H Vacant . 85
Annex I (normative) Modified test circuit for short-circuit testing of semiconductor

motor controllers and starters . 86
Annex J (informative) Flowchart for constructing bypassed semiconductor controllers
tests . 88
Annex K (normative) Extended functions within electronic overload relays . 89
Bibliography . 94

Figure 1 – Semiconductor motor control devices . 13
Figure 2 – Connecting methods . 22
Figure 3 – Thermal memory test . 36
Figure 4 – Multiple of current setting limits for ambient air temperature compensated
time-delay overload relays . 62
Figure C.1 – Examples of time-current withstand characteristic . 77
Figure F.1 – Thermal stability test profile . 80
Figure F.2 – Overload capability test profile . 81
Figure F.3 – Blocking and commutating capability test profile . 82
Figure G.1 – Diagrammatic representation of an ECD . 83
Figure G.2 – Single supply and control input . 83
Figure G.3 – Single supply and control input . 84
Figure G.4 – Controllers with an internal control supply and control input only . 84
Figure I.1 − Modified circuit for short-circuit testing of semiconductor devices . 86
Figure I.2 − Time line for the short-circuit test of 9.3.4.1.6 . 87
Figure K.1 – Test circuit for the verification of the operating characteristic of a residual

current electronic overload relay . 93

Table 1 – Functional possibilities of semiconductor motor control devices . 14
Table 2 – Utilization categories . 26
Table 3 – Relative levels of severity . 27
Table 4 – Trip classes of overload relays . 29
Table 5 – Limits of operation of time-delay overload relays when energized on all poles . 35
Table 6 – Limits of operation of three-pole time-delay overload relays when energized
on two poles only . 37
Table 7 – Temperature rise limits for insulated coils in air and in oil . 40
Table 8 – Intermittent duty test cycle data . 40
Table 9 – Minimum overload current withstand time (T ) in relation to overload current
x
ratio (X) and corresponding to overload relay trip class (see Table 19) . 43
a
Table 10 – Minimum requirements for thermal stability test conditions . 43

60947-4-2 © IEC:2011 – 5 –
Table 11 – Minimum requirements for overload capability test conditions . 44
Table 12 – Minimum requirements and conditions for performance testing with an
induction motor load . 44
Table 13 – Making and breaking capacity test; making and breaking conditions
according to utilization categories for the mechanical switching device of hybrid motor
controllers H1, H2, H3 and for certain forms of bypassed controllers . 46
Table 14 – Conventional operational performance making and breaking conditions
according to utilization categories for the mechanical switching device of hybrid motor
controllers H1B, H2B, H3B and for certain forms of bypassed controllers . 46
Table 15 – Specific acceptance or performance criteria when EM disturbances are
present . 49
Table 16 – Thermal stability test specifications . 57
Table 17 – Initial case temperature requirements . 57
Table 18 – Blocking and commutating capability test specifications . 59
Table 19 – Terminal disturbance voltage limits for conducted radio-frequency emission . 67
Table 20 – Radiated emissions test limits . 67
Table A.1 – Main circuit terminal markings . 70
Table C.1 – Test conditions . 76
Table K.1 – Operating time of residual current electronic overload relays . 90

– 6 – 60947-4-2 © IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-2: Contactors and motor-starters –
AC semiconductor motor controllers and starters

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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 60947-4-2 has been prepared by subcommittee 17B: Low-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This third edition replaces the second edition published in 1999 and its Amendments 1 (2001)
and 2 (2006). It is a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition and its amendments:
• updated EMC normative references and associated requirements,
• new references to IEC 60947-1,
• marking of electronic relays without thermal memory,
• marking of tripping time at 0 °C ambient or below,
• new test requirements for limits of operation of time-delay overload relays,

60947-4-2 © IEC:2011 – 7 –
• new classes of overload current withstand time,
• damp heat, salt mist, vibration and shock tests,
• short-circuit test in the smallest enclosure,
• update of the routine and sampling tests.
This standard shall be read in conjunction with IEC 60947-1:2007, Low-voltage switchgear
and controlgear – Part 1: General rules. The provisions of the general rules are applicable to
this standard, where specifically called for.
The text of this standard is based on the following documents:
FDIS Report on voting
17B/1734/FDIS 17B/1741/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.
A list of all the parts in the IEC 60947 series, under the general title Low-voltage switchgear
and controlgear, can be found on the IEC website.
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.
– 8 – 60947-4-2 © IEC:2011
INTRODUCTION
This standard covers low-voltage a.c. semiconductor motor controllers and starters that have
many capabilities and features beyond the simple starting and stopping of an induction motor,
such as controlled starting and stopping, manoeuvring and controlled running.
The generic term “controller” is used in this standard wherever the unique features of the
power semiconductor switching elements are the most significant points of interest. The
generic term “starter” is used wherever the consequences of operating the power semi-
conductor switching elements, together with suitable overload protective means, are the most
significant points of interest. Specific designations (for example form 1, form HxB, etc.) are
used wherever the unique features of various configurations comprise significant points of
interest.
60947-4-2 © IEC:2011 – 9 –
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-2: Contactors and motor-starters –
AC semiconductor motor controllers and starters

1 Scope
This standard applies to a.c. semiconductor motor controllers and starters, which may include
a series mechanical switching device, intended to be connected to circuits, the rated voltage
of which does not exceed 1 000 V a.c.
This standard characterizes a.c. semiconductor motor controllers and starters with and
without bypass means.
AC semiconductor motor controllers and starters dealt with in this standard are not normally
designed to interrupt short-circuit currents. Therefore, suitable short-circuit protection (see
8.2.5) should form part of the installation, but not necessarily of the a.c. semiconductor motor
controller or starter.
In this context, this standard gives requirements for a.c. semiconductor motor controllers and
starters associated with separate short-circuit protective devices.
This standard does not apply to
– continuous operation of a.c. motors at motor speeds other than the normal speed;
– semiconductor equipment, including semiconductor contactors (see 2.2.13 of
IEC 60947-1:2007) controlling non-motor loads;
– electronic a.c. power controllers covered by IEC 60146 series.
Contactors, overload relays and control circuit devices used in a.c. semiconductor motor
controllers and starters should comply with the requirements of their relevant product
standard. Where mechanical switching devices are used, they should meet the requirements
of their own IEC product standard, and the additional requirements of this standard.
The object of this standard is to state as follows:
– the characteristics of a.c. semiconductor motor controllers and starters and associated
equipment;
– the conditions with which a.c. semiconductor motor controllers and starters comply with
reference to
a) their operation and behaviour;
b) their dielectric properties;
c) the degrees of protection provided by their enclosures where applicable;
d) their construction;
– the tests intended for confirming that these conditions have been met, and the methods to
be adopted for these tests;
– the information to be given with the equipment, or in the manufacturer's literature.
NOTE For the purpose of this standard, the term "controller" may be used instead of
"a.c. semiconductor motor controller".

– 10 – 60947-4-2 © IEC:2011
2 Normative references
The following referenced documents are indispensable for the application 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 60034-1:2010, Rotating electrical machines – Part 1: Rating and performance
IEC 60085:2007, Electrical insulation – Thermal evaluation and designation
IEC 60269-1:2006, Low-voltage fuses – Part 1: General requirements
Amendment 1 (2009)
IEC 60410:1973, Sampling plans and procedures for inspection by attributes
IEC 60664 (all parts), Insulation coordination for equipment within low-voltage systems
IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules
IEC 61000-4 (all parts), Electromagnetic compatibility (EMC) – Part 4: Testing and
measurement techniques
CISPR 11:2009, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
Amendment 1 (2010)
3 Terms, definitions, symbols and abbreviations
3.1 General
For the purposes of this document, the terms and definitions of Clause 2 of IEC 60947-
1:2007, as well as the following terms, definitions, symbol and abbreviations apply.
3.2 Alphabetical index of terms
Reference
A
a.c. semiconductor motor controller . 3.3.2
B
burst (of pulses or oscillations) . 3.5.7
bypassed controller . 3.4.31
C
CO operation . 3.4.32
controlled acceleration . 3.4.6
controlled deceleration . 3.4.7
controlled running . 3.4.8
current-limit function . 3.4.4
E
electromagnetic compatibility [EMC] . 3.5.1
electromagnetic disturbance . 3.5.3
electromagnetic emission . 3.5.2

60947-4-2 © IEC:2011 – 11 –
F
FULL-ON (state of controllers) . 3.4.12
H
hybrid motor controller or starter, form HxA (where x = 1, 2 or 3) . 3.4.1
hybrid motor controller or starter, form HxB . 3.4.2
I
inhibit time . 3.4.28
J
jam sensitive electronic overload relay . 3.4.27
M
manoeuvre . 3.4.5
minimum load current . 3.4.13
O
O operation . 3.4.33
OFF-state . 3.4.14
OFF-state leakage current [I ]. 3.4.15
L
OFF-time . 3.4.30
ON-state . 3.4.11
ON-time . 3.4.29
OPEN position . 3.4.3
operating capability . 3.4.18
operating cycle (of a controller) . 3.4.17
operation (of a controller). 3.4.16
overload current profile . 3.4.19
P
phase loss sensitive overload relay or release . 3.4.23
prospective current (of a circuit and with respect to a switching device or a fuse) . 3.4.9
prospective locked rotor current [I ] . 3.4.10
LRP
R
radio (frequency) disturbance . 3.5.4
radio frequency interference [RFI] . 3.5.5
rating index . 3.4.20
S
semiconductor direct on line (DOL) motor controller (form 3) . 3.3.5
semiconductor motor controller (form 1) . 3.3.3
semiconductor motor starter (form 1, form 2, form 3) . 3.3.6
semiconductor soft-start motor controller (form 2) . 3.3.4
semiconductor switching device . 3.3.1
stall sensitive electronic overload relay . 3.4.26
T
transient (adjective and noun) . 3.5.6
trip-free controller or starter . 3.4.22
tripping operation (of a controller or starter) . 3.4.21
U
under-current relay or release .
...

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