IEC 60947-4-3:2014

Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - AC semiconductor controllers and contactors for non-motor loads

IEC 60947-4-3:2014 applies to a.c. semiconductor non-motor load controllers and contactors intended for performing electrical operations by changing the state of a.c. electric circuits between the ON-state and the OFF-state. Typical applications are classified by utilization categories given in Table 2. This second edition cancels and replaces the first edition published in 1999, Amendment 1:2006 and Amendment 2:2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) Update of the marking requirements (6.1);
b) Update of the EMC requirements (8.3.2); and
c) Update of the tests requirements (9.3.1, 9.4, 9.4.1.1, 9.4.1.2, 9.4.2.1, 9.4.2.2, 9.4.2.3, 9.4.2.4, 9.4.2.6).
This publication is to be read in conjunction with IEC 60947-1:2007.

Appareillage à basse tension - Partie 4-3: Contacteurs et démarreurs de moteurs - Gradateurs et contacteurs à semiconducteurs pour charges, autres que des moteurs, à courant alternatif

L'IEC 60947-4-3:2014 s'applique aux gradateurs et démarreurs à semiconducteurs à courant alternatif pour des charges autres que des moteurs prévus pour effectuer des man uvres électriques en changeant l'état des circuits électriques à courant alternatif entre l'état passant et l'état bloqué. Des applications typiques classées par catégorie d'emploi sont données au Tableau 2. Cette deuxième édition annule et remplace la première édition parue en 1999, l'Amendement 1:2006 et l'Amendement 2:2011. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) mise à jour des exigences de marquage (6.1);
b) mise à jour des exigences de CEM (8.3.2); et
c) mise à jour des exigences d'essais (9.3.1, 9.4, 9.4.1.1, 9.4.1.2, 9.4.2.1, 9.4.2.2, 9.4.2.3, 9.4.2.4, 9.4.2.6).
Cette publication doit être lue conjointement avec la CEI 60947-1:2007.

General Information

• Status: Published
• Publication Date: 06-May-2014
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• ICS: 31.180 - Printed circuits and boards
• Technical Committee: SC 121A - Low-voltage switchgear and controlgear
• Current Stage: DELPUB - Deleted Publication
• Start Date: 14-Jul-2020
• Completion Date: 13-Apr-2018

Relations

• Revised: IEC 60947-4-3:2020 - Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - Semiconductor controllers and semiconductor contactors for non-motor loads
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-4-3:1999 - Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - AC semiconductor controllers and contactors for non-motor loads
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-4-3:1999/AMD2:2011 - Amendment 2 - Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - AC semiconductor controllers and contactors for non-motor loads
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-4-3:1999/COR1:2000 - Corrigendum 1 - Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - AC semiconductor controllers and contactors for non-motor loads
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-4-3:1999/AMD1:2006 - Amendment 1 - Low-voltage switchgear and controlgear - Part 4-3: Contactors and motor-starters - AC semiconductor controllers and contactors for non-motor loads
• Effective Date: 05-Sep-2023

Overview

IEC 60947-4-3:2014 is an International Electrotechnical Commission (IEC) standard that specifies requirements for low-voltage switchgear and controlgear, specifically focusing on AC semiconductor controllers and contactors designed for non-motor loads. This standard covers devices used to perform electrical switching operations by changing the state of AC electric circuits between ON and OFF. Applicable primarily to non-motor applications, these controllers and contactors ensure reliable and safe management of electrical circuits in a wide range of industrial and commercial settings.

First published in 1999, the 2014 edition is a technical revision that updates marking, electromagnetic compatibility (EMC) requirements, and test procedures. It must be read in conjunction with IEC 60947-1:2007, which provides general rules for low-voltage switchgear and controlgear.

Key Topics

• Scope and Purpose: IEC 60947-4-3 is intended for AC semiconductor non-motor load controllers and contactors, applicable to tasks like switching resistive heating elements, lighting controls, transformers, and capacitor banks. It clarifies utilization categories and operational functions through detailed classifications.

• Classification and Characteristics: The standard defines device types including solid-state and hybrid controllers, rated voltages, current capacities, and duty cycles. It emphasizes performance characteristics such as overload handling, short-circuit current ratings, and coordination with protective devices.

• Marking and Product Information: Updated marking requirements improve traceability and ensure users receive accurate product data. This includes terminal identification for main, control, and auxiliary circuits, fostering proper installation and maintenance.

• Construction and Performance: Detailed constructional requirements specify materials, insulation clearances, actuator design, enclosures, and earthing provisions. Performance requirements cover operating conditions, temperature rise limits, dielectric properties, and operational reliability over normal and overload conditions.

• EMC Requirements: The 2014 edition enhances electromagnetic compatibility criteria, including emission and immunity tests, to ensure devices operate reliably without electromagnetic interference in complex electrical environments.

• Testing Procedures: Comprehensive test regimens validate construction compliance and performance, including type, routine, sampling, and special tests. Amendments have updated test sequences related to normal load, overload, and short-circuit conditions, ensuring safety and performance under real-world stresses.

Applications

IEC 60947-4-3 compliant AC semiconductor controllers and contactors for non-motor loads are widely used in:

• Heating Element Control: Managing resistive loads in industrial ovens, kilns, and heating systems with precision switching and reduced mechanical wear.

• Lighting Systems: Switching electric discharge lamps and incandescent lighting in commercial and industrial environments, offering enhanced reliability and reduced flicker.

• Transformers and Capacitors: Switching capacitor banks and transformers, pivotal for power factor correction and voltage regulation without disrupting power quality.

• Industrial Automation: Integration into control panels and machinery for streamlined power control of non-motor loads, contributing to increased productivity and safety.

• Energy Management Systems: Facilitating load switching in energy-efficient installations to optimize power consumption and reduce operational costs.

Related Standards

• IEC 60947-1:2007 - General rules for low-voltage switchgear and controlgear, complementing IEC 60947-4-3 with overarching principles and requirements.

• IEC 60947-4-1 - Covers contactors and motor-starters for motor loads, often used alongside 4-3 devices when motor and non-motor load switching is combined.

• IEC 61000 Series - Electromagnetic compatibility standards applicable for assessing EMC performance as per IEC 60947-4-3’s updated requirements.

• National and Regional Standards - Many countries harmonize their electrical equipment regulations with IEC standards, ensuring international interoperability and compliance.

---

IEC 60947-4-3:2014 serves as a vital standard for manufacturers, designers, and users of AC semiconductor controllers and contactors for non-motor loads, supporting safe, efficient, and standardized electrical control solutions. Adhering to this standard ensures devices meet rigorous performance, safety, and EMC criteria essential for modern low-voltage electrical systems.

Standards Content (Sample)

IEC 60947-4-3 ®
Edition 2.0 2014-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –
Part 4-3: Contactors and motor-starters – AC semiconductor controllers and
contactors for non-motor loads

Appareillage à basse tension –
Partie 4-3: Contacteurs et démarreurs de moteurs – Gradateurs et contacteurs à
semiconducteurs pour charges, autres que des moteurs, à courant alternatif

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IEC 60947-4-3 ®
Edition 2.0 2014-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –

Part 4-3: Contactors and motor-starters – AC semiconductor controllers and

contactors for non-motor loads

Appareillage à basse tension –

Partie 4-3: Contacteurs et démarreurs de moteurs – Gradateurs et contacteurs à

semiconducteurs pour charges, autres que des moteurs, à courant alternatif

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XC
ICS 29.130.20, 31.180 ISBN 978-2-8322-1567-8

– 2 – IEC 60947-4-3:2014 © IEC 2014
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms, definitions, symbols and abbreviations . 10
3.1 Terms and definitions concerning a.c. semiconductor (non-motor-load)
control devices . 11
3.1.1 AC semiconductor controllers and contactors (solid-state
contactors) (see Figure 1) . 11
3.1.2 Hybrid controllers and contactors (see Figure 1) . 14
3.2 Vacant . 18
3.3 Symbols and abbreviations . 18
4 Classification . 18
5 Characteristics of a.c. semiconductor controllers and contactors . 19
5.1 Summary of characteristics . 19
5.2 Type of equipment . 19
5.3 Rated and limiting values for main circuits . 22
5.3.1 Rated voltages . 22
5.3.2 Currents . 22
5.3.3 Rated frequency . 22
5.3.4 Rated duty . 22
5.3.5 Normal load and overload characteristics . 23
5.3.6 Rated conditional short-circuit current . 24
5.4 Utilization category . 24
5.4.1 Assignment of ratings based on the results of tests . 25
5.5 Control circuits . 26
5.6 Auxiliary circuits . 26
5.7 Vacant . 26
5.8 Coordination with short-circuit protective devices (SCPD) . 26
6 Product information . 26
6.1 Nature of information . 26
6.2 Marking . 28
6.3 Instructions for installation, operation and maintenance . 28
7 Normal service, mounting and transport conditions . 28
7.1 Normal service conditions . 28
7.1.1 Ambient air temperature . 28
7.1.2 Altitude . 28
7.1.3 Atmospheric conditions . 28
7.1.4 Shock and vibrations . 29
7.2 Conditions during transport and storage . 29
7.3 Mounting . 29
7.4 Electrical system disturbances and influences . 29
8 Constructional and performance requirements . 29
8.1 Constructional requirements . 29
8.1.1 General . 29

8.1.2 Materials . 29
8.1.3 Current-carrying parts and their connections . 29
8.1.4 Clearances and creepage distances . 29
8.1.5 Actuator . 30
8.1.6 Indication of the contact position . 30
8.1.7 Additional requirements for equipment suitable for isolation . 30
8.1.8 Terminals . 30
8.1.9 Additional requirements for equipment provided with a neutral
pole . 30
8.1.10 Provisions for protective earthing . 30
8.1.11 Enclosures for equipment . 30
8.1.12 Degrees of protection of enclosed equipment . 30
8.1.13 Conduit pull-out, torque and bending with metallic conduits . 30
8.2 Performance requirements . 30
8.2.1 Operating conditions . 30
8.2.2 Temperature rise . 32
8.2.3 Dielectric properties . 34
8.2.4 Normal load and overload performance requirements . 35
8.2.5 Coordination with short-circuit protective devices . 42
8.3 EMC requirements . 42
8.3.1 General . 42
8.3.2 Emission . 43
8.3.3 Immunity . 43
9 Tests . 45
9.1 Kinds of tests . 45
9.1.1 General . 45
9.1.2 Type tests . 45
9.1.3 Routine tests . 45
9.1.4 Sampling tests . 45
9.1.5 Special tests . 46
9.2 Compliance with constructional requirements . 46
9.3 Compliance with performance requirements . 46
9.3.1 Test sequences . 46
9.3.2 General test conditions . 47
9.3.3 Performance under no load, normal load and overload
conditions . 47
9.3.4 Performance under short-circuit conditions . 54
9.3.5 Disponible . 58
9.4 General . 58
9.4.1 EMC emission tests . 58
9.4.2 EMC immunity tests . 59
9.5 Routine and sampling tests . 61
9.5.1 General . 61
9.5.2 Operation and operating limits . 61
9.5.3 Dielectric tests . 61
Annex A (normative) Marking and identification of terminals . 62
A.1 General . 62
A.2 Marking and identification of terminals of controller and contactors . 62
A.2.1 Marking and identification of terminals of main circuits . 62

– 4 – IEC 60947-4-3:2014 © IEC 2014
A.2.2 Marking and identification of terminals of control circuits . 62
A.2.3 Marking and identification of auxiliary circuits . 62
Annex B (informative) Typical service conditions for controllers and contactors . 65
B.1 Control of resistive heating elements . 65
B.2 Switching of electric discharge lamp controls . 65
B.3 Switching of incandescent lamps . 66
B.4 Switching of transformers. 66
B.5 Switching of capacitor banks . 66
Annex C Vacant . 67
Annex D Vacant . 68
Annex E Vacant . 69
Annex F (informative) Operating capability. 70
Annex G Vacant . 73
Annex H Vacant . 74
Annex I (normative) Modified test circuit for short-circuit testing of semiconductor
contactors and controllers . 75
Annex J (informative) Flowchart for constructing bypassed semiconductor controllers
tests . 77
Bibliography . 78

Figure 1 – Graphical possibilities of controllers . 13
Figure 2 – Methods of connecting . 21
Figure F.1 – Thermal stability test profile . 70
Figure F.2 – Overload capability test profile . 71
Figure F.3 – Blocking and commutating capability test profile . 72
Figure I.1 – Modified circuit for short-circuit testing of semiconductor devices . 75
Figure I.2 – Time line for the short-circuit test of 9.3.4.1.6 . 76

Table 1 – Functional possibilities of controllers and contactors . 14
Table 2 – Utilization categories . 25
Table 3 – Relative levels of severity . 25
Table 4 – Temperature rise limits for insulated coils in air and in oil . 34
Table 5 – Intermittent duty test cycle data . 34
Table 6 – Minimum overload current withstand time (T ) in relation to overload current
x
ratio (X) . 36
Table 7 − Minimum requirements for thermal stability test conditions . 37
Table 8 – Minimum requirements for overload capability test conditions . 38
Table 9 – Minimum requirements and conditions for performance testing, including
blocking and commutating capability . 39
Table 10 – Making and breaking capacity test – Making and breaking conditions
according to utilization categories for the mechanical switching device of hybrid
semiconductor controller and contactor H4, H5 . 40
Table 11 – Conventional operational performance – Making and breaking conditions
according to utilization categories for the mechanical switching device of hybrid
controllers and contactors H4B, H5B . 41
Table 12 – Specific performance criteria when EM disturbances are present . 44

Table 13 – Thermal stability test specifications . 51
Table 14 – Initial case temperature requirements . 52
Table 15 – Terminal disturbance voltage limits for conducted radiofrequency emission . 59
Table 16 – Radiated emissions test limits . 59
Table A.1 – Main circuit terminal markings . 62

– 6 – IEC 60947-4-3:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-3: Contactors and motor-starters –
AC semiconductor controllers and
contactors for non-motor loads

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60947-4-3 has been prepared by subcommittee 17B: Low-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This second edition cancels and replaces the first edition published in 1999, Amendment
1:2006 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Update of the marking requirements (6.1);
b) Update of the EMC requirements (8.3.2); and
c) Update of the tests requirements (9.3.1, 9.4, 9.4.1.1, 9.4.1.2, 9.4.2.1, 9.4.2.2, 9.4.2.3,
9.4.2.4, 9.4.2.6).
The text of this standard is based on the following documents:
FDIS Report on voting
121A/2/FDIS 121A/14/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 parts in the IEC 60947 series, published under the general title Low-voltage
switchgear and controlgear, can be found on the IEC website.
This standard shall be read in conjunction with IEC 60947-1, 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 provisions of the general rules (IEC 60947-1) are applicable to this standard, where
specifically called for. Clauses and subclauses thus applicable, as well as tables, figures, and
annexes, are identified by reference to IEC 60947-1, for example 1.2.3 of IEC 60947-1:2007,
Amendment 1 (2010), Table 4 of IEC 60947-1:2007, Amendment 1 (2010) or Annex A of
IEC 60947-1:2007.
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 – IEC 60947-4-3:2014 © IEC 2014
INTRODUCTION
This part of IEC 60947 covers low-voltage a.c. semiconductor controllers and contactors
(solid-state contactors) intended for the use with non-motor loads. As controllers, they have
many capabilities beyond the simple switching on and off of non-motor loads. As contactors,
they perform the same functions as mechanical contactors, but utilize one or more
semiconductor switching devices in their main poles.
The devices may be single-pole or multi-pole (see 2.3.1 of IEC 60947-1:2007,). This standard
refers to complete devices rated as a unit incorporating all necessary heat-sinking material
and terminals. It includes devices with all necessary terminals, which are supplied with or
without heat-sink in knocked-down form for combination by the users, when the manufacturer
gives with the device detailed information about choosing the heat-sink and mounting the
device on the heat-sink.
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 "contactor" is used in this standard wherever the feature of simple switching on
and off is the most significant point of interest. Specific designations (for example, form 4,
form HxB, etc.) are used wherever the unique features of various configurations comprise
significant points of interest.

LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 4-3: Contactors and motor-starters –
AC semiconductor controllers and
contactors for non-motor loads

1 Scope
This part of IEC 60947 applies to a.c. semiconductor non-motor load controllers and
contactors intended for performing electrical operations by changing the state of a.c. electric
circuits between the ON-state and the OFF-state. Typical applications are classified by
utilization categories given in Table 2.
As controllers, they may be used to reduce the amplitude of the r.m.s. a.c. voltage on the load
terminals from that of the applied voltage – either continuously or for a specified period of
time. The half-wave period of the a.c. wave form remains unchanged from that of the applied
voltage.
They may include a series mechanical switching device and are intended to be connected to
circuits, the rated voltage of which does not exceed 1 000 V a.c.
This standard characterizes controllers and contactors for use with or without bypass
switching devices.
The semiconductor controllers and contactors dealt with in this standard are not normally
intended 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 controller itself.
In this context, this standard gives requirements for semiconductor controllers and contactors
associated with separate short-circuit protective devices.
This standard does not apply to:
− operation of a.c. and d.c. motors;
− low-voltage a.c. semiconductor motor controllers and starters covered by IEC 60947-4-2;
− electronic a.c. power controllers covered by the IEC 60146 series;
− all-or-nothing solid-state relays.
Contactors and control-circuit devices used in semiconductor controllers and contactors
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
a) the characteristics of semiconductor controllers and contactors and associated equipment;
b) the conditions with which semiconductor controllers and contactors should comply with
reference to:
− their operation and behaviour;
− their dielectric properties;
− the degrees of protection provided by their enclosures, where applicable;

– 10 – IEC 60947-4-3:2014 © IEC 2014
− their construction;
c) the tests intended for confirming that these conditions have been met, and the methods to
be adopted for these tests;
d) the information to be given with the equipment or in the manufacturer's literature.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60269-1:2006, Low-voltage fuses – Part 1: General requirements
IEC 60410:1973, Sampling plans and procedures for inspection by attributes
IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules
Amendment 1:2010
IEC 61000-4 (all parts), Electromagnetic compatibility (EMC) – Part 4:Testing and
measurement techniques
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
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
For the purposes of this document, the terms and definitions given in Clause 2 of IEC 60947-
1:2007, Amendment 1 (2010), as well as the following additional terms and definitions apply:
Reference
A
AC semiconductor controller . 3.1.1.1
B
Bypassed controller . 3.1.24
C
Current-limit function . 3.1.3
D
Defined-point switching (of a semiconductor controller) . 3.1.14.4.1
F
Full-on (state of controllers) . 3.1.10
H
Hybrid controllers or contactors, form HxA (where x = 4 or 5) . 3.1.2.1
Hybrid controllers or contactors, form HxB . 3.1.2.2
I
Instantaneous switching function . 3.1.14.3
L
Load control . 3.1.4
M
Minimum load current . 3.1.11
Minimum load current detection . 3.1.11.1
O
OFF-state . 3.1.12
OFF-state leakage current . 3.1.13
OFF-time . 3.1.23
ON-state . 3.1.9
ON-time . 3.1.22
OPEN position . 3.1.2.3
Operating capability . 3.1.16
Operating cycle (of a controller) . 3.1.15
Operation (of a controller) . 3.1.14
Overcurrent protective means OCPM . 3.1.21
Overload current profile . 3.1.17

R
Ramp-down . 3.1.6
Ramp-up . 3.1.5
Random point switching (of a semiconductor controller) . 3.1.14.4.3
Rating index . 3.1.18
S
Semiconductor controller (form 4) . 3.1.1.1.1
Semiconductor direct-on-line (DOL) controller (form 5) . 3.1.1.1.3
Switching function . 3.1.14.1
Switching point . 3.1.14.4
T
Trip-free controller . 3.1.20
Tripping operation (of a controller) . 3.1.19
Z
Zero-point switching (of a semiconductor controller) . 3.1.14.4.2

3.1 Terms and definitions concerning a.c. semiconductor (non-motor-load) control
devices
3.1.1 AC semiconductor controllers and contactors (solid-state contactors) (see
Figure 1)
3.1.1.1
a.c. semiconductor controller
semiconductor switching device that provides a switching function for an a.c. electrical load
(non-motor load) and an OFF-state
Note 1 to entry: Because dangerous levels of leakage currents (see 3.1.13) can exist in a semiconductor
controller in the OFF-state, the load terminals should be considered to be live at all times.
Note 2 to entry: In a circuit where the current passes through zero (alternately or otherwise), the effect of "not
making" the current following such a zero value is equivalent to breaking the current.
Note 3 to entry: See 2.2.3 of IEC 60947-1:2007 for the definition of semiconductor switching device.
3.1.1.1.1
semiconductor controller (form 4)
a.c. semiconductor controller in which the switching function may comprise any method
specified by the manufacturer. It provides control functions which may include any
combination of ramp-up, load control or ramp-down. A full-on state may also be provided
3.1.1.1.2
Vacant
– 12 – IEC 60947-4-3:2014 © IEC 2014
3.1.1.1.3
semiconductor direct-on-line controller (form 5)
semiconductor DOL controller (form 5)
special form of a.c. semiconductor controller in which the switching function is limited to the
full-voltage, unramped method only and where the additional control function is limited to
providing FULL-ON (also known as a semiconductor contactor or solid-state contactor)
Note 1 to entry: It is a device (see 2.2.13 of IEC 60947-1:2007) which performs the function of a contactor by
utilizing a semiconductor switching device (see 2.2.3 of IEC 60947-1:2007). It has only one position of rest (OFF-
state or Open state in the case of an HxB hybrid controller) and is operated by the application of a control signal. It
is capable of carrying load currents as well as changing the state of the said load (electrical circuit) between the
FULL-ON and the OFF-states (Open) under normal circuit conditions including operating overload conditions.

3.1.1.2
Vacant
Device
L T
Controller
U
(all forms) e
U
c
IEC  1408/14
L T
a
Hybrid controller HxA
U
e
where x = 4 or 5
U
c2
U
c1
IEC  1409/14
L T
b
Hybrid controller HxB
U
e
where x = 4 or 5
U
c1
IEC  1410/14
Parallel mechanical
contact
L
T
Semiconductor controller
(Forms 4,5)
IEC  1411/14
Bypassed controller
Parallel mechanical
contact
Hybrid controller
c
Series
Bypassed hybrid controller
L T
Semiconductor
mechanical
controller
contact
(Forms H × A, H × B)
IEC  1412/14
a
Two separate controls for the controller and the series mechanical switching device respectively.
b
One control only for the series mechanical switching device.
c
For other configurations, tests can be suitably adapted by agreement between the user and the manufacturer.
Figure 1 – Graphical possibilities of controllers

– 14 – IEC 60947-4-3:2014 © IEC 2014
Table 1 – Functional possibilities of controllers and contactors
Device Form 4 Form 5
Semiconductor OFF-state Not available
controller
Ramp-up
Load control
FULL-ON state
Ramp-down
Semiconductor Not available OFF-state
DOL contactor
Switch-on function
FULL-ON state
Hybrid H4A: H5A:
a
controller HxA
– open state – open state
where x = 4 or 5
– OFF-state – OFF-state
– ramp-up – switch-on function
– load control – FULL-ON state
– FULL-ON state
– ramp-down
Hybrid H4B: H5B:
b
controller HxB
– open state – open state
where x = 4 or 5
– ramp-up – switch-on function
– load control – FULL-ON state
– FULL-ON state
– ramp-down
a
Two separate controls for the controller and the series mechanical switching device, respectively.
b
One control only for the series mechanical switching device.

3.1.2 Hybrid controllers and contactors (see Figure 1)
3.1.2.1
hybrid controllers form HxA (where x = 4 or 5)
hybrid contactors form HxA (where x = 4 or 5)
form 4, or form 5 semiconductor controller in series with a mechanical switching device all
rated as a unit
Note 1 to entry: Separate control commands are provided for the series mechanical switching device and the
semiconductor controller or contactor. All the control functions appropriate to the form of controller specified are
provided together with an OPEN position.
3.1.2.2
hybrid controllers form HxB (where x = 4 or 5)
hybrid contactors form HxB (where x = 4 or 5)
form 4 or form 5 semiconductor controller in series with a mechanical switching device all
rated as a unit
Note 1 to entry: A single control command is provided for both the series mechanical switching device and the
semiconductor controller or contactor. All the control functions appropriate to the form of controller specified are
provided with the exception of an OFF-state.
3.1.2.3
OPEN position
condition of a hybrid semiconductor controller when the series mechanical switching device is
in the OPEN position
Note 1 to entry: See 2.4.21 of IEC 60947-1:2007 for the definition of open position.
3.1.3
current-limit function
ability of the controller to limit the load current to a specified value
Note 1 to entry: It does not include the ability to limit the instantaneous current under conditions of short circuit.
3.1.4
load control
any deliberate operation which causes changes in the effective power available to the load
through variation of either
− an imposed operating cycle (i.e. variation of the cyclic duration factor F and/or the number
of operating cycles per hour S, see 5.3.4.6)
or
− the load terminal voltage (for example, through phase-angle control)
or
− a combination of these
Note 1 to entry: Switch-on is a mandatory form of load control that is recognized separately.
Note 2 to entry: Load control can be performed by a form 5 controller, if an external switching device or contr
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