IEC 60947-8:2003+AMD1:2006+AMD2:2011 CSV

Low-voltage switchgear and controlgear - Part 8: Control units for built-in thermal protection (PTC) for rotating electrical machines

IEC 60947-8:2003+A1:2006+A2:2011 specifies rules for control units, which perform the switching functions in response to the thermal detectors incorporated in rotating electrical machines according to IEC 60034-11, and the industrial application. It specifies rules for that type of system comprising a positive temperature coefficient (PTC) thermistor detector having particular characteristics, and its associated control unit. The PT100 detectors are covered by IEC 60751, where the resistor values are given according to the temperatures of the detector. The present rules lay down the characteristics of association of this particular positive temperature coefficient thermistor detector and its associated control unit (designated "Mark A detector" and "Mark A control unit"), when they are used in thermal protection systems. The technical content is therefore identical to the base edition and its amendments and has been prepared for user convenience. It bears the edition number 1.2. A vertical line in the margin shows where the base publication has been modified by amendments 1 and 2.
This publication is to be read in conjunction with  IEC 60947-1:2007
This consolidated version consists of the first edition (2003), its amendment 1 (2006) and its amendment 2 (2011). Therefore, no need to order amendments in addition to this publication.

Appareillage à basse tension - Partie 8: Unités de commande pour la protection thermique incorporée (CTP) aux machines électriques tournantes

La CEI 60947-8:2003+A1:2006+A2:2011 spécifie les règles pour les unités de commande, qui réalisent les fonctions de commutation en réponse aux détecteurs thermiques incorporés aux machines électriques tournantes selon la CEI 60034-11, et l'application industrielle. Elle spécifie les règles pour ce type de dispositif comprenant un détecteur à thermistance à coefficient de température positif (CTP) ayant des caractéristiques particulières, et son unité de commande associée. Les détecteurs PT100 sont couverts par la CEI 60751, où les valeurs de résistance sont données selon les températures du détecteur. Les présentes règles fixent les caractéristiques de l'association de ce détecteur à thermistance à coefficient de température positif particulier et de son unité de commande associée (désignés par "Détecteur A" et "Unité de commande A"), lorsqu'ils sont utilisés dans des dispositifs de protection thermique. Le contenu technique de cette version consolidée est donc identique à celui de l'édition de base et à ses amendements; cette version a été préparée par commodité pour l'utilisateur. Elle porte le numéro d'édition 1.2. Une ligne verticale dans la marge indique où la publication de base a été modifiée par les amendements 1 et 2.
Cette publication doit être lue conjointement avec la  CEI 60947-1:2007
Cette version consolidée comprend la première édition (2003), son amendement 1 (2006) et son amendement 2 (2011). Il n'est donc pas nécessaire de commander les amendements avec cette publication.

General Information

• Status: Published
• Publication Date: 17-Oct-2011
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SC 121A - Low-voltage switchgear and controlgear
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 28-Jul-2021

Standards Content (Sample)

IEC 60947-8
®

Edition 1.2 2011-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 8: Control units for built-in thermal protection (PTC) for rotating electrical
machines

Appareillage à basse tension –
Partie 8: Unités de commande pour la protection thermique incorporée (CTP)
aux machines électriques tournantes

IEC 60947-8:2003+A1:2006+A2:2011

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
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---------------------- Page: 2 ----------------------
IEC 60947-8
®

Edition 1.2 2011-10

INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 8: Control units for built-in thermal protection (PTC) for rotating electrical
machines

Appareillage à basse tension –
Partie 8: Unités de commande pour la protection thermique incorporée (CTP)
aux machines électriques tournantes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX CP
ICS 29.130.20 ISBN 978-2-88912-722-1

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – 60947-8  IEC:2003+A1:2006+A2:2011
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, symbols and abbreviations . 8
3.1 Terms and definitions . 8
3.2 Symbols and abbreviations . 11
4 Classification . 12
5 Characteristics . 12
5.1 General . 12
5.2 Type of equipment . 12
5.3 Rated electrical values of protection systems . 14
5.4 Rated electrical values of characteristic variation thermal detectors . 15
5.5 Rated voltage of the detector circuit of the control unit . 15
6 Product information . 15
6.1 Nature of information . 15
6.2 Marking . 16
6.3 Instructions for installation, operation and maintenance . 16
7 Normal service, mounting and transport conditions . 16
8 Constructional and performance requirements . 16
8.1 Constructional requirements . 16
8.2 Performance requirements . 17
8.3 Electromagnetic compatibility (EMC) . 19
8.3.1 General . 19
8.3.2 Immunity . 19
8.3.3 Emission . 20
9 Tests . 21
9.1 Kinds of tests . 21
9.2 Compliance with constructional requirements . 22
9.3 Compliance with performance requirements . 22
9.4 EMC tests . 28
9.5 Routine and sampling tests . 30

Annex A (normative) Thermal detectors used in thermal protection systems . 31
Annex B (normative) Special tests . 33

Figure A.1 – Characteristic curve of a typical Mark A detector . 32

Table 1 – Tests for EMC – Immunity . 29
Table 2 – Vibration test parameters . 19

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60947-8  IEC:2003+A1:2006+A2:2011 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 8: Control units for built-in thermal protection (PTC)
for rotating electrical machines



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 60947-8 has been prepared by subcommittee 17B: Low-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This consolidated version of IEC 60947-8 consists of the first edition (2003) [documents
17B/1276/FDIS and 17B/1282/RVD], its amendment 1 (2006) [documents 17B/1477/FDIS and
17B/1504/RVD] and its amendment 2 (2011) [documents 17B/1732/FDIS and 17B/1739/RVD].
The technical content is therefore identical to the base edition and its amendments and has
been prepared for user convenience.
It bears the edition number 1.2.
A vertical line in the margin shows where the base publication has been modified by
amendments 1 and 2.
This standard shall be used in conjunction with IEC 60947-1: General rules.

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– 4 – 60947-8  IEC:2003+A1:2006+A2:2011
The provisions of the general rules dealt with in IEC 60947-1 are applicable to this standard,
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 (e.g. 1.2.3 of
IEC 60947-1, Table 4 of IEC 60947-1 or Annex A of IEC 60947-1, etc.).
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of the base publication and its amendments 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.

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

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60947-8  IEC:2003+A1:2006+A2:2011 – 5 –
INTRODUCTION
Thermal protection systems which are based on the principle of monitoring the temperature of
the protected parts constitute a simple and effective means of protecting rotating electrical
machines against excessive temperature rises, including those caused by faults in the cooling
system, or excessively high ambient temperature, whereas systems of protection based only
on monitoring the current absorbed may not ensure this type of protection.
Since the operating temperature and response times of thermal protection systems are fixed
in advance, they may not be adjusted in relation to the conditions of use of the machine and
they may not be completely effective for all fault conditions or improper use of the machine.
A thermal protection system in accordance with this standard may consist of a characteristic
change thermal detector which has an associated control unit to convert a point on the
characteristic of the detector to a switching function. A very large number of thermal
protection systems are in use and, in all cases, the machine manufacturer will fit the detectors
in the machine. The machine manufacturer will either supply the control unit with the machine
or specify particulars of the control unit to be used.
It is also customary for the control units to be considered as part of the control system and not
necessarily supplied with the machine. For this reason it is considered necessary to have an
interchangeable system, where the characteristics of association between the detector and
the control unit are specified. This particular system is not considered superior in any way to
other systems complying with the requirements of this standard, but in some fields the
practice is likely to be that this interchangeable system will be used, as indicated by
the designation “Mark A”.

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– 6 – 60947-8  IEC:2003+A1:2006+A2:2011
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 8: Control units for built-in thermal protection (PTC)
for rotating electrical machines



1 Scope
This part of IEC 60947 specifies rules for control units, which perform the switching functions
in response to the thermal detectors incorporated in rotating electrical machines according to
IEC 60034-11, and the industrial application.
It specifies rules for that type of system comprising a positive temperature coefficient (PTC)
thermistor detector having particular characteristics, and its associated control unit.
The PT100 detectors are covered by IEC 60751, where the resistor values are given
according to the temperatures of the detector.
The present rules lay down the characteristics of association of this particular positive
temperature coefficient thermistor detector and its associated control unit (designated “Mark A
detector” and “Mark A control unit”), when they are used in thermal protection systems.
NOTE It is not possible to specify all the requirements for the operating characteristics of a control unit, as they
are dependent on some aspects of the thermal detectors. Some aspects of the requirements of the thermal
protector system can only be specified when account is taken of the characteristics of the rotating machine to be
protected and the method of installation of the detector within the machine.
For these reasons, for each characteristic it is necessary to specify who is responsible for stating the required
values and who is responsible for compliance with the requirement and for carrying out any confirmatory test.
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 60034-11:2004, Rotating electrical machines – Part 11: Thermal protection
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-6:1995, Environmental testing – Part 2: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-27:1987, Environmental testing – Part 2: Tests – Test Ea and guidance: Shock
IEC 60410:1973, Sampling plans and procedures for inspection by attributes
IEC 60417:2002, Graphical symbols for use on equipment
IEC 60738-1:1998, Thermistors – Directly heated positive step-function temperature
coefficient – Part 1: Generic specification

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60947-8  IEC:2003+A1:2006+A2:2011 – 7 –
IEC 60751:1983, Industrial platinum resistance thermometer sensors
Amendment 1 (1986)
Amendment 2 (1995)
IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules
IEC 60947-5-1:2003, Low-voltage switchgear and controlgear – Part 5-1: Control circuit
devices and switching elements – Electromechanical control circuit devices
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) - Part 4-3: Testing and
measurement techniques - Radiated, radio-frequency, electromagnetic field immunity test
Amendment 1 (2007)
Amendment 2 (2010)
IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
Amendment 1 (2010)
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
Corrigendum 1 (2009)
IEC 61000-4-6:2008, Electromagnetic compatibility (EMC) – Part 4-6: Testing and
measurement techniques – Immunity to conducted disturbances, induced by radio-frequency
fields
IEC 61000-4-8:2009, Electromagnetic compatibility (EMC) – Part 4-8: Testing and
measurement techniques – Power frequency magnetic field immunity test
IEC 61000-4-11:2004, Electromagnetic compatibility (EMC) – Part 4-11: Testing and
measurement techniques – Voltage dips, short interruptions and voltage variations immunity
tests
IEC 61000-4-13:2002, Electromagnetic compatibility (EMC) – Part 4-13: Testing and
measurement techniques – Harmonics and interharmonics including mains signalling at a.c.
power port, low-frequency immunity tests
Amendment 1 (2009)
CISPR 11:2009, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
Amendment 1 (2010)
CISPR 22:2008, Information technology equipment – Radio disturbance characteristics –
Limits and methods of measurement

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– 8 – 60947-8  IEC:2003+A1:2006+A2:2011
3 Terms, definitions, symbols and abbreviations
For the purposes of this document, relevant definitions of IEC 60947-1, together with the
following definitions, apply.
3.1 Terms and definitions
Reference
A
Abrupt characteristic change thermal detector . 3.1.14

B
Built-in thermal protection . 3.1.1

C
Category of thermal protection . 3.1.12
Characteristic variation thermal detector . 3.1.13
Control circuit . 3.1.16
Control system . 3.1.5
Control unit . 3.1.15
Control unit with dynamic wire break detection. 3.1.25
Control unit with short-circuit detection within the thermal detector circuit . 3.1.24

D
Detector operating temperature (TNF) . 3.1.17

E
Electrically separated contact elements . 3.1.20

M
Mark A control unit . 3.1.23
Mark A detector . 3.1.22
Maximum temperature after tripping . 3.1.11

P
Protected part . 3.1.6
PTC thermistor detector . 3.1.21

R
Reset temperature . 3.1.19

S
Switching type thermal detector . 3.1.4
System operating temperature (TFS) . 3.1.18

T
Thermal detector. 3.1.3
Thermal overload with rapid variation . 3.1.8
Thermal overload with slow variation . 3.1.7
Thermal protection system . 3.1.2
Thermal protection with detector . 3.1.10
Thermally critical part of a machine . 3.1.9
3.1.1
built-in thermal protection
protection of certain parts (called protected parts) of a rotating electrical machine against
excessive temperatures resulting from certain conditions of thermal overload, achieved by
means of a thermal protection system, the whole or part of which is a thermally sensitive
device incorporated within the machine

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60947-8  IEC:2003+A1:2006+A2:2011 – 9 –
3.1.2
thermal protection system
system intended to ensure the thermal protection of a rotating electrical machine by means of
a built-in thermal detector together with a control unit
3.1.3
thermal detector
electrical insulated device (component), sensitive to temperature only, which will initiate a
switching function in the control system when its temperature reaches a predetermined level
3.1.4
switching type thermal detector
thermal detector which causes a direct operation of a switching element
NOTE The combination of the thermal detector and the switching element is rated as a unit and mounted in the
rotating electrical machine.
3.1.5
control system
system to translate a particular point on the characteristic of a thermal detector to a switching
function on the supply to the rotating electrical machine
NOTE The system is capable of being reset (either manually or automatically) when the temperature falls to the
reset value.
3.1.6
protected part
part of a rotating electrical machine, the temperature of which is limited to a predetermined
value by the action of the thermal protection system
3.1.7
thermal overload with slow variation
slow temperature rise above the normal operating temperature
NOTE 1 The variation of the temperature of the protected part is sufficiently slow for the temperature of the
thermal detector to follow without appreciable delay.
NOTE 2 A thermal overload with slow variation may be caused, for instance, by:
− defects in ventilation or in the ventilation system, for example partial blocking of the ventilation ducts,
excessive dust, dirt on the windings or on the cooling ribs of the frame;
− an excessive rise in the ambient temperature or in the temperature of the cooling medium;
− gradually increasing mechanical overload;
− prolonged voltage drop or over-voltage in the machine supply;
− excessive duty in a machine.
3.1.8
thermal overload with rapid variation
rapid rise of temperature above the normal operating temperature
NOTE 1 The variation of the temperature of the protected part may be too rapid for the temperature of the thermal
detector to follow without delay. This may result in a significant temperature difference between the thermal
detector and the protected part.
NOTE 2 A thermal overload with rapid variation may be caused, for instance, by stalling the machine or in certain
circumstances, by phase failure or by starting under abnormal conditions (inertia too high, voltage too low, load
torque abnormally high).
3.1.9
thermally critical part of a machine
part of a machine in which the temperature most rapidly reaches its dangerous value
NOTE A part of a machine which is thermally critical in the case of thermal overload with slow variation may not
be so for a thermal overload with rapid variation.

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– 10 – 60947-8  IEC:2003+A1:2006+A2:2011
3.1.10
thermal protection with detector
form of protection where the part of the machine in which the thermal detector(s) is (are)
incorporated is the thermally critical part
3.1.11
maximum temperature after tripping
maximum value of the temperature which is reached by the protected part of the machine
during the period which follows tripping by the thermal protection system, for thermal overload
with rapid variation
3.1.12
category of thermal protection
indication of the permissible temperature levels on the windings of a machine when subjected
to the thermal overload
3.1.13
characteristic variation thermal detector
thermal detector which has a characteristic the variation of which, related
...