SIST EN IEC 60947-4-2:2023

Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - Semiconductor motor controllers, starters and soft-starters (IEC 60947-4-2:2020)

IEC 60947-4-2:2020 applies to semiconductor motor controllers, starters and soft-starters which can include a series mechanical switching device, intended to be connected to circuits the rated voltage of which does not exceed 1 000 V AC.
This fourth edition cancels and replaces the third edition published in 2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- scope exclusions;
- editorial correction of notes and hanging paragraphs;
- reference to IEC 62683-1;
- safety aspects related to:
- general aspects;
- limited energy circuits;
- electronic circuits;
- mention of dedicated wiring accessories;
- power consumption measurement;
- alignment to IEC 60947-1:2020.

Niederspannungsschaltgeräte - Teil 4-2: Schütze und Motorstarter - Halbleiter-Motor-Steuergeräte und -Starter für Wechselspannungen (IEC 60947-4-2:2020)

Appareillage à basse tension - Partie 4-2: Contacteurs et démarreurs de moteurs - Gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif (IEC 60947-4-2:2020)

L’IEC 60947-4-2:2020 s’applique aux gradateurs, démarreurs et démarreurs progressifs à semiconducteurs de moteurs qui peuvent comprendre un appareil mécanique de connexion en série, destiné à être relié à des circuits dont la tension assignée ne dépasse pas 1 000 V en courant alternatif.
Cette quatrième édition annule et remplace la troisième édition parue en 2011. Cette édition constitue une révision technique.
La présente édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
- exclusions du domaine d’application;
- correction rédactionnelle des notes et des alinéas en suspens;
- référence à l’IEC 62683-1;
- aspects de sécurité relatifs aux points suivants:
- aspects généraux;
- circuits à énergie limitée;
- circuits électroniques;
- mention des accessoires de câblage dédiés;
- mesure de la puissance consommée;
- alignement sur l’IEC 60947-1:2020.
La version française de la norme n’a pas été soumise au vote.

Nizkonapetostne stikalne in krmilne naprave - 4-2. del: Kontaktorji in motorski zaganjalniki - Polprevodniški krmilniki motorjev, zaganjalniki motorjev in mehki zaganjalniki na izmenični tok (IEC 60947-4-2:2020)

Ta del standarda IEC 60947 se uporablja za polprevodniške krmilnike motorjev, zaganjalnike motorjev in mehke zaganjalnike na izmenični tok, ki lahko vključujejo serijsko mehansko stikalno napravo in so namenjeni priključitvi na tokokroge z nazivno izmenično napetostjo, ki ne presega 1000 V.
Ta dokument opisuje lastnosti polprevodniških krmilnikov in zaganjalnikov motorjev z možnostjo obvoda in brez nje.
Ta dokument se ne uporablja za:
– polprevodniške krmilnike in zaganjalnike motorjev, ki se uporabljajo za stalno delovanje motorjev na izmenični tok pri hitrostih motorjev, ki niso običajne1;
– elektromehanske kontaktorje in zunanje preobremenitvene releje (glej standard IEC 60947-4-1);
– napravo za zaščito pred kratkim stikom, ki je povezana s polprevodniškimi krmilniki ali zaganjalniki motorjev (glej standarde IEC 60947-4-1 (MPSD), IEC 60947-2 in IEC 60947-3);
– polprevodniško opremo, vključno s polprevodniškimi kontaktorji (glej točko 3.4.13 standarda IEC 60947-1:2020), ki krmilijo nemotorske obremenitve (glej standard IEC 60947-4-3);
– polprevodniške krmilnike in zaganjalnike motorjev, ki se uporabljajo za tokokroge rotorjev1;
– električne pogonske sisteme z nastavljivo hitrostjo (glej skupino standardov IEC 61800);
– uporabo izdelka v eksplozivnih atmosferah (glej skupino standardov IEC 60079);
– zahteve za programsko in vdelano programsko opremo1;
OPOMBA 1: Smernice o vgrajeni programski opremi so navedene v standardu IEC TR 63201.
– vidike kibernetske varnosti (glej standard IEC TS 63208).
Za kontaktorje, preobremenitvene releje in naprave s krmilnimi tokokrogi, ki se uporabljajo v polprevodniških krmilnikih in zaganjalnikih motorjev na izmenični tok, se šteje, da izpolnjujejo zahteve ustreznega standarda za izdelek. Kadar se uporabljajo mehanske stikalne naprave, se šteje, da izpolnjujejo zahteve svojega standarda za izdelek IEC in dodatne zahteve tega dokumenta.
Cilj tega dokumenta je navesti:
– lastnosti polprevodniških krmilnikov, zaganjalnikov in mehkih zaganjalnikov na izmenični tok ter povezane opreme;
– pogoje, ki jih morajo izpolnjevati polprevodniški krmilniki, zaganjalniki in mehki zaganjalniki na izmenični tok v zvezi z naslednjim:
a) njihovim delovanjem in obnašanjem v normalnih in nenormalnim delovnih razmerah, vključno z delovanjem pri presežnem toku;
b) njihovimi dielektričnimi lastnostmi;
c) stopnjami zaščite, doseženimi z okrovi, kjer je primerno;
d) njihovo konstrukcijo, vključno z zaščito pred električnim udarom, požarno ogroženostjo in mehaničnim tveganjem;
– preskuse, katerih cilj je potrditi, da so bili ti pogoji in metode izvajanja teh preskusov izpolnjeni;
– informacije, ki jih je treba predložiti z opremo ali navesti v navodilih proizvajalca.
OPOMBA 2: V tem dokumentu se namesto izraza »polprevodniški krmilnik motorja« uporablja izraz »krmilnik«.

General Information

• Status: Published
• Publication Date: 28-Mar-2023
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SKA - Switchgear and control gear
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Mar-2023
• Due Date: 12-May-2023
• Completion Date: 29-Mar-2023
• Directive: 2014/30/EU - Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility (recast)
• Directive: 2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
• Mandate: M/511 - Mandate to CEN, CENELEC and ETSI relating to harmonised standards in the field of the Low Voltage Directive
• Mandate: M/552 - [C(2016) 7641 final] Standardisation request as regards harmonised standards in support of Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility
• Ref Project: EN IEC 60947-4-2:2023 - Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - Semiconductor motor controllers, starters and soft-starters

Relations

• Replaces: SIST EN 60947-4-2:2012 - Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - AC semiconductor motor controllers and starters (IEC 60947-4-2:2011)
• Effective Date: 01-May-2023
• Amended By: SIST EN IEC 60947-4-2:2023/A1:2025 - Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters - Semiconductor motor controllers, starters and soft-starters (IEC 60947-4-2:2020/AMD1:2024)
• Effective Date: 01-Feb-2025

Overview

EN IEC 60947-4-2:2023 (CLC adoption of IEC 60947-4-2:2020) is the fourth edition of the low‑voltage switchgear and controlgear standard that specifies requirements for semiconductor motor controllers, starters and soft‑starters (which may include a series mechanical switching device) intended for connection to AC circuits with rated voltage up to 1 000 V AC. This edition replaces the 2011 edition and constitutes a technical revision aligned with IEC 60947‑1:2020.

Key topics and technical requirements

The standard addresses product design, testing, marking and safe use. Important technical topics include:

• Scope and exclusions - clarified limits of applicability for semiconductor motor controllers, starters and soft‑starters.
• Terms, classification and symbols - definitions specific to semiconductor motor control and starters.
• Rated and limiting values - rated voltages, currents, frequency, duty cycles and conditional short‑circuit currents.
• Utilization categories and coordination - assignment of ratings and coordination with short‑circuit protective devices (SCPD).
• Control, auxiliary and overload protection - requirements for control circuits, auxiliary circuits and relays/releases (overload relays).
• Constructional requirements - materials, current‑carrying parts, terminals, clearances and creepage distances, enclosures and grounding provisions.
• Safety aspects - enhanced treatment of general safety, limited energy circuits, electronic circuits and dedicated wiring accessories.
• Performance tests - temperature‑rise, dielectric properties, normal load/overload performance, fault and abnormal condition assessments.
• Energy and power considerations - stored charge energy circuits, limited energy sources and power consumption measurement requirements.
• Product information - marking, installation/operation/maintenance instructions and environmental information.

The 2023 edition also adds a reference to IEC 62683‑1 and includes editorial corrections and changes to notes and paragraph handling.

Applications and users

EN IEC 60947‑4‑2:2023 is essential for:

• Manufacturers and designers of semiconductor motor controllers, soft‑starters and motor‑starters
• Panel builders and OEMs integrating soft‑starters into motor drives and control panels
• Electrical engineers specifying motor control equipment for industrial, commercial and infrastructure projects
• Test laboratories and certification bodies performing compliance and type testing
• Installation, maintenance and safety personnel responsible for correct selection, wiring and servicing

Typical applications include motor starting and soft starting of pumps, fans, conveyors and other AC induction motor loads where reduced inrush, torque control and electrical protection are required.

Related standards

• EN IEC 60947‑1:2020 - General rules for low‑voltage switchgear and controlgear
• IEC 62683‑1 - referenced in the 2023 edition
• Other referenced EMC, machine and safety standards (listed in the normative references) for coordinated compliance.

For specification or compliance checks, consult the full text of EN IEC 60947‑4‑2:2023 and associated normative references.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2023
Nizkonapetostne stikalne in krmilne naprave - 4-2. del: Kontaktorji in motorski
zaganjalniki - Polprevodniški krmilniki motorjev, zaganjalniki motorjev in mehki
zaganjalniki na izmenični tok (IEC 60947-4-2:2020)
Low-voltage switchgear and controlgear - Part 4-2: Contactors and motor-starters -
Semiconductor motor controllers, starters and soft-starters (IEC 60947-4-2:2020)
Niederspannungsschaltgeräte - Teil 4-2: Schütze und Motorstarter - Halbleiter-Motor-
Steuergeräte und -Starter für Wechselspannungen (IEC 60947-4-2:2020)
Appareillage à basse tension - Partie 4-2: Contacteurs et démarreurs de moteurs -
Gradateurs et démarreurs à semiconducteurs de moteurs à courant alternatif (IEC 60947
-4-2:2020)
Ta slovenski standard je istoveten z: EN IEC 60947-4-2:2023
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 IEC 60947-4-2

NORME EUROPÉENNE
EUROPÄISCHE NORM March 2023
ICS 29.130.20 Supersedes EN 60947-4-2:2012
English Version
Low-voltage switchgear and controlgear - Part 4-2: Contactors
and motor-starters - Semiconductor motor controllers, starters
and soft-starters
(IEC 60947-4-2:2020)
Appareillage à basse tension - Partie 4-2: Contacteurs et Niederspannungsschaltgeräte - Teil 4-2: Schütze und
démarreurs de moteurs - Gradateurs, démarreurs et Motorstarter - Halbleiter-Motor-Steuergeräte, Starter und
démarreurs progressifs à semiconducteurs de moteurs Sanftstarter
(IEC 60947-4-2:2020) (IEC 60947-4-2:2020)
This European Standard was approved by CENELEC on 2023-01-11. 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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60947-4-2:2023 E

European foreword
The text of document 121A/353/FDIS, future edition 4 of IEC 60947-4-2, prepared by SC 121A "Low-
voltage switchgear and controlgear" of IEC/TC 121 "Switchgear and controlgear and their assemblies
for low voltage" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-10-11
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-01-11
document have to be withdrawn
This document supersedes EN 60947-4-2:2012 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a Standardization Request given to CENELEC by the
European Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60947-4-2:2020 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 standard indicated:
IEC 60034-30-1 NOTE Approved as EN 60034-30-1
IEC 60068-2-2:2007 NOTE Approved as EN 60068-2-2:2007 (not modified)
IEC 60079 (series) NOTE Approved as EN IEC 60079-7 (series)
IEC 60085:2007 NOTE Approved as EN 60085:2008 (not modified)
IEC 60269-1:2006 NOTE Approved as EN 60269-1:2007 (not modified)
IEC 60364-1 NOTE Approved as HD 60364-1
IEC 60664 (series) NOTE Approved as EN 60664 (series)
IEC 60947-2 NOTE Approved as EN 60947-2
IEC 60947-3 NOTE Approved as EN IEC 60947-3
IEC 60947-4-1 NOTE Approved as EN IEC 60947-4-1
IEC 60947-4-3 NOTE Approved as EN 60947-4-3
IEC 60990:2016 NOTE Approved as EN 60990:2016 (not modified)
IEC 61000-4 (series) NOTE Approved as EN 61000-4 (series)
IEC 61032 NOTE Approved as EN 61032
IEC 61800 (series) NOTE Approved as EN 61800 (series)
IEC 62443 (series) NOTE Approved as EN IEC 62443 (series)
IEC 62477-1:2012 NOTE Approved as EN 62477-1:2012 (not modified) +A11:2014
IEC 62683-1 NOTE Approved as EN 62683-1
IEC/TR 63201 NOTE Approved as CLC IEC/TR 63201
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60034-1 2017 Rotating electrical machines - Part 1: - -
Rating and performance
IEC 60445 - Basic and safety principles for man- EN IEC 60445 -
machine interface, marking and
identification - Identification of equipment
terminals, conductor terminations and
conductors
IEC 60715 - Dimensions of low-voltage switchgear and EN 60715 -
controlgear - Standardized mounting on
rails for mechanical support of switchgear,
controlgear and accessories
IEC 60730-1 - Automatic electrical controls - Part 1: - -
General requirements
IEC 60947-1 2020 Low-voltage switchgear and controlgear - EN IEC 60947-1 2021
Part 1: General rules
IEC 61000-3-2 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-3-2 -
3-2: Limits - Limits for harmonic current
emissions (equipment input current 16 ≤ A
per phase)
IEC 61000-3-3 - Electromagnetic compatibility (EMC) - Part EN 61000-3-3 -
3-3: Limits - Limitation of voltage changes,
voltage fluctuations and flicker in public
low-voltage supply systems, for equipment
with rated current ≤ 16 A per phase and
not subject to conditional connection
IEC 61000-3-11 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-3-11 -
3-12: Limits - Limitation of voltage
changes, voltage fluctuations and flicker in
public low-voltage supply systems -
Equipment with rated current ≤ 75 A and
subject to conditional connection
IEC 61000-3-12 - Electromagnetic compatibility (EMC) - Part EN 61000-3-12 -
3-12: Limits - Limits for harmonic currents
produced by equipment connected to
public low-voltage systems with input
current >16 A and ≤ 75 A per phase
IEC 61140 2016 Protection against electric shock - EN 61140 2016
Common aspects for installation and
equipment
CISPR 11 2015 Industrial, scientific and medical equipment EN 55011 2016
- Radio-frequency disturbance
characteristics - Limits and methods of
measurement
+ A1 2016  + A1 2017
- -  + A11 2020
ISO 2859-1 1999 Sampling procedures for inspection by - -
attributes - Part 1: Sampling schemes
indexed by acceptance quality limit (AQL)
for lot-by-lot inspection
IEC 60947-4-2 ®
Edition 4.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –

Part 4-2: Contactors and motor-starters – Semiconductor motor controllers,

starters and soft-starters
Appareillage à basse tension –

Partie 4-2: Contacteurs et démarreurs de moteurs – Gradateurs, démarreurs et

démarreurs progressifs à semiconducteurs de moteurs

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-8451-3

– 2 – IEC 60947-4-2:2020 © IEC 2020
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 11
3 Terms, definitions, symbols and abbreviated terms . 12
3.1 Terms and definitions . 12
3.1.1 Terms and definitions concerning the types of semiconductor motor
controllers and starters . 12
3.1.2 Terms and definitions concerning semiconductor motor controllers and
starters . 14
3.1.3 Terms and definitions concerning safety aspects . 17
3.1.4 Alphabetical index of terms . 18
3.2 Symbols and abbreviated terms . 20
4 Classification . 20
5 Characteristics of semiconductor motor controllers and starters . 20
5.1 Summary of characteristics . 20
5.2 Type of equipment . 21
5.2.1 Kind of equipment . 21
5.2.2 Number of poles . 21
5.2.3 Kind of current . 21
5.2.4 Interrupting medium (air, vacuum, etc.) . 21
5.2.5 Operating conditions of the equipment . 21
5.3 Rated and limiting values for main circuits . 22
5.3.1 Rated voltages . 22
5.3.2 Currents. 24
5.3.3 Rated frequency . 25
5.3.4 Duty cycle values and sequences . 25
5.3.5 Normal load and overload characteristics . 25
5.3.6 Rated conditional short-circuit current . 27
5.3.7 Semiconductor motor controller power losses . 27
5.4 Utilization category . 28
5.4.1 General. 28
5.4.2 Assignment of ratings based on the results of tests . 28
5.5 Control circuits . 29
5.6 Auxiliary circuits . 29
5.7 Characteristics of relays and releases (overload relays). 29
5.7.1 Summary of characteristics . 29
5.7.2 Types of relay or release . 30
5.7.3 Characteristic values . 30
5.7.4 Designation and current settings of overload relays . 31
5.7.5 Time-current characteristics of overload relays . 31
5.7.6 Influence of ambient air temperature . 32
5.8 Coordination with short-circuit protective devices (SCPD) . 32
6 Product information . 32
6.1 Nature of information . 32
6.2 Marking . 34

IEC 60947-4-2:2020 © IEC 2020 – 3 –
6.3 Instructions for installation, operation, maintenance, decommissioning and
dismantling . 34
6.4 Environmental information . 34
7 Normal service, mounting and transport conditions . 35
7.1 Normal service conditions . 35
7.1.1 Ambient air temperature . 35
7.1.2 Altitude . 35
7.1.3 Atmospheric conditions . 35
7.1.4 Shock and vibrations. 35
7.2 Conditions during transport and storage . 35
7.3 Mounting . 35
7.4 Electrical system disturbances and influences . 35
8 Constructional and performance requirements . 36
8.1 Constructional requirements . 36
8.1.1 General. 36
8.1.2 Materials . 36
8.1.3 Current-carrying parts and their connections . 37
8.1.4 Clearances and creepage distances . 37
8.1.5 Actuator . 37
8.1.6 Indication of the contact position . 37
8.1.7 Additional requirements for equipment suitable for isolation . 37
8.1.8 Terminals . 37
8.1.9 Additional requirements for equipment provided with a neutral pole . 38
8.1.10 Provisions for protective earthing . 38
8.1.11 Enclosures for equipment . 38
8.1.12 Degrees of protection of enclosed equipment. 38
8.1.13 Conduit pull-out, torque and bending with metallic conduits . 38
8.1.14 Limited energy source . 38
8.1.15 Stored charge energy circuit . 40
8.1.16 Fault and abnormal conditions . 40
8.1.17 Short-circuit and overload protection of ports . 41
8.2 Performance requirements . 41
8.2.1 Operating conditions . 41
8.2.2 Temperature-rise . 46
8.2.3 Dielectric properties . 47
8.2.4 Normal load and overload performance requirements . 48
8.2.5 Coordination with short-circuit protective devices . 53
8.3 EMC requirements . 54
8.3.1 General. 54
8.3.2 Immunity . 54
8.3.3 Emission . 56
9 Tests . 56
9.1 Kinds of tests . 56
9.1.1 General. 56
9.1.2 Type tests . 56
9.1.3 Routine tests . 57
9.1.4 Sampling tests . 57
9.1.5 Special tests . 57
9.2 Compliance with constructional requirements . 58

– 4 – IEC 60947-4-2:2020 © IEC 2020
9.2.1 General. 58
9.2.2 Electrical performance of screwless-type clamping units . 58
9.2.3 Ageing test for screwless-type clamping units . 59
9.2.4 Limited energy source test . 59
9.2.5 Breakdown of components . 59
9.2.6 Wire flexing test . 60
9.3 Compliance with performance requirements . 60
9.3.1 Test sequences . 60
9.3.2 General test conditions . 61
9.3.3 Performance under no load, normal load, and overload conditions . 61
9.3.4 Performance under short-circuit conditions . 72
9.4 EMC tests . 75
9.4.1 General. 75
9.4.2 EMC immunity tests . 76
9.4.3 EMC emission tests . 76
9.5 Routine and sampling tests . 79
9.5.1 General. 79
9.5.2 Operation and operating limits . 79
9.5.3 Dielectric tests . 79
Annex A (normative) Marking and identification of terminals . 81
A.1 General . 81
A.2 Marking and identification of terminals of semiconductor controllers and
starters . 81
A.2.1 Marking and identification of terminals of main circuits . 81
A.2.2 Marking and identification of terminals of control circuits. 81
A.3 Marking and identification of terminals of overload relays . 81
Annex B (xxx) . 82
Annex C (normative) Coordination at the crossover current between the starter and
associated SCPD . 83
C.1 General and definitions . 83
C.1.1 General. 83
C.1.2 Terms and definitions . 83
C.2 Condition for the test for the verification of coordination at the crossover
current by a direct method . 83
C.3 Test currents and test circuits . 83
C.4 Test procedure and results to be obtained . 84
C.4.1 Test procedure . 84
C.4.2 Results to be obtained . 84
C.5 Verification of coordination at the crossover current by an indirect method . 84
C.5.1 General. 84
C.5.2 Test for I . 84
cd
C.5.3 Time-current characteristic withstand capability of controllers/starters . 85
Annex D (xxx) . 87
Annex E (xxx) . 88
Annex F (informative) Operating capability . 89
Annex G (informative) Rated operational currents and rated operational powers of
switching devices for electrical motors . 93
G.1 General . 93
G.2 Rated operational powers and rated operational currents . 93

IEC 60947-4-2:2020 © IEC 2020 – 5 –
Annex H (xxx) . 97
Annex I (normative) Modified test circuit for short-circuit testing of semiconductor
motor controllers and starters . 98
Annex J (xxx) . 100
Annex K (xxx) . 101
Annex L (normative) Examples of overvoltage category reduction . 102
L.1 General . 102
L.2 Insulation to the surroundings . 102
L.2.1 Circuits connected directly to the supply mains . 102
L.2.2 Insulation between circuits . 103
Annex M (xxx) . 107
Annex N (normative) Additional requirements and tests for equipment with protective
separation . 108
N.1 General . 108
N.2 Definitions. 108
N.3 Requirements . 108
N.3.1 Test method for implementing protective impedance . 108
N.3.2 Touch current measurement . 109
Bibliography . 111

Figure 1 – Semiconductor motor control devices . 13
Figure 2 – Connecting methods . 24
Figure 3 – Thermal memory test . 44
Figure 4 – Multiple of current setting limits for ambient air temperature compensated
time-delay overload relays . 71
Figure C.1 – Examples of time-current withstand characteristic. 86
Figure F.1 – Thermal stability test profile . 90
Figure F.2 – Overload capability test profile . 91
Figure F.3 – Blocking and commutating capability test profile . 92
Figure I.1 – Modified circuit for short-circuit testing of semiconductor devices . 98
Figure I.2 – Time line for the short-circuit test of 9.3.4.1.6 . 99
Figure L.1 – Basic insulation evaluation for circuits connected directly to the origin of
the installation mains supply . 102
Figure L.2 – Basic insulation evaluation for circuits connected directly to the mains
supply . 103
Figure L.3 – Basic insulation evaluation for equipment not permanently connected to
the mains supply . 103
Figure L.4 – Basic insulation evaluation for insulation between circuits connected
directly to the origin of the installation mains supply and that are declared galvanically
separated . 104
Figure L.5 – Basic insulation evaluation for insulation between circuits connected
directly to the mains supply and that are declared galvanically separated . 104
Figure L.6 – Basic insulation evaluation for insulation between circuits not permanently
connected directly to the mains supply and that are declared galvanically separated . 105
Figure L.7 – Basic insulation evaluation for insulation between circuits connected
directly to the origin of the installation mains supply and that are declared galvanically
separated where internal SPDs are used . 105

– 6 – IEC 60947-4-2:2020 © IEC 2020
Figure L.8 – Basic insulation evaluation for insulation between circuits connected
directly to the mains supply and that are declared galvanically separated where
internal SPDs are used . 106
Figure L.9 – Basic insulation evaluation for insulation between circuits connected
directly to the mains supply and that are declared galvanically separated . 106
Figure N.1 – Protection by means of protective impedance . 109
Figure N.2 – Measuring instrument . 110

Table 1 – Utilization categories . 28
Table 2 – Relative levels of severity . 29
Table 3 – Trip classes of overload relays . 31
Table 19 – Limits for limited energy sources without an over-current protective device . 39
Table 20 – Limits for limited energy sources with an over-current protective device . 39
Table 21 – Limits for limited energy source with current limiting impedance . 40
Table 4 – Limits of operation of time-delay overload relays when energized on all poles . 43
Table 5 – Limits of operation of three-pole time-delay overload relays when energized
on two poles only . 45
Table 6 – Temperature-rise limits for insulated coils in air and in oil . 47
Table 7 – Minimum overload current withstand time (T ) in relation to overload current
x
ratio (X) and corresponding to overload relay trip class (see Table 3) . 49
Table 8 – Minimum requirements for thermal stability test conditions . 50
Table 9 – Prospective locked rotor current by utilization categories . 50
Table 10 – Minimum requirements for overload capability test conditions . 51
Table 11 – Making and breaking capacity test; making and breaking conditions
according to utilization categories for the mechanical switching device . 52
Table 12 – Conventional operational performance making and breaking conditions
according to utilization categories for the mechanical switching device . 53
Table 13 – Specific performance criteria when EM disturbances are present . 55
Table 14 – Thermal stability test specifications . 66
Table 15 – Initial case temperature requirements . 66
Table 16 – Minimum requirements and conditions for performance testing with an
induction motor load . 68
Table 17 – Terminal disturbance voltage limits for conducted radio-frequency emission
(AC mains power port) . 78
Table 18 – Radiated emissions test limits . 79
Table A.1 – Main circuit terminal markings . 81
Table C.1 – Test conditions . 85
Table G.1 – Rated operational powers and rated operational currents of motors . 94
Table L.1 – Drawing keys . 102

IEC 60947-4-2:2020 © IEC 2020 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-2: Contactors and motor-starters –
Semiconductor motor controllers, starters and soft-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,
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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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 121A: Low-voltage
switchgear and controlgear, of IEC technical committee 121: Switchgear and controlgear and
their assemblies for low voltage.
This fourth edition cancels and replaces the third edition published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• scope exclusions;
• editorial correction of notes and hanging paragraphs;
• reference to IEC 62683-1;
– 8 – IEC 60947-4-2:2020 © IEC 2020
• safety aspects related to:
– general aspects;
– limited energy circuits;
– electronic circuits;
• mention of dedicated wiring accessories;
• power consumption measurement;
• alignment to IEC 60947-1:2020.
The provisions of the general rules dealt with IEC 60947-1 are applicable to this part of
IEC 60947 series where specifically called for. Clauses and subclauses, tables, figures and
annexes of the general rules thus applicable are identified by reference to IEC 60947-1:2020.
The text of this standard is based on the following documents:
FDIS Report on voting
121A/353/FDIS 121A/360/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.
IEC 60947-4-2:2020 © IEC 2020 – 9 –
INTRODUCTION
This document covers low-voltage semiconductor motor controllers, starters and soft-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 document wherever reference is made to
elements of power semiconductor switching devices.
The generic term “starter” is used in this document wherever reference is made to the
elements of power semiconductor switching devices together with suitable overload protective
devices.
– 10 – IEC 60947-4-2:2020 © IEC 2020
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-2: Contactors and motor-starters –
Semiconductor motor controllers, starters and soft-starters

1 Scope
This part of IEC 60947 applies to semiconductor motor controllers, starters and soft-starters
which can include a series mechanical switching device, intended to be connected to circuits
the rated voltage of which does not exceed 1 000 V AC.
This document characterizes semiconductor motor controllers and starters with and without
bypass means.
This document does not apply to:
– semiconductor motor controllers and starters used for continuous operation of AC motors
at motor speeds other than the normal speed ;
– electromechanical contactors and external overload relays (see IEC 60947-4-1);
– short-circuit protective device associated with semiconductor motor controllers and
starters (see IEC 60947-4-1 (MPSD), IEC 60947-2 and IEC 60947-3);
– semiconductor equipment, including semiconductor contactors (3.4.13 of
IEC 60947-1:2020) controlling non-motor loads (see IEC 60947-4-3);
– semiconductor motor controllers and starters used for rotor circuits ;
– adjustable speed electrical power drive systems (see IEC 61800 series);
– use of the product within explosive atmospheres (see IEC 60079 series);
– software and firmware requirements ;
NOTE 1 Guidance on embedded software is given in IEC TR 63201.
– cyber security aspects (see IEC TS 63208).
Contactors, overload relays and control circuit devices used in semiconductor motor
controllers and starters are considered compliant with the requirements of their relevant
product standard.
...