Rotating electrical machines - Test methods and apparatus for the measurement of the operational characteristics of brushes (IEC 60773:2021)

This document applies to test methods for the measurement of the operational characteristics of brushes designed to operate on commutating and slip ring machines under specified test conditions. By extension some tests may be relevant for other kinds of sliding electrical contacts for electrical appliances.

Drehende elektrische Maschinen - Prüfverfahren und -einrichtungen für die Messung der Betriebseigenschaften von Kohlebürsten (IEC 60773:2021)

Machines électriques tournantes - Méthodes d'essai et appareils pour le mesurage des caractéristiques opérationnelles des balais (IEC 60773:2021)

IEC 60773:2021 s'applique aux méthodes d'essai pour le mesurage des caractéristiques opérationnelles des balais conçus pour fonctionner sur des machines avec commutation et sur des machines à bagues, dans des conditions d'essai spécifiées. Par extension, certains essais peuvent être pertinents pour d’autres types de contacts électriques glissants pour appareils électriques. Cette deuxième édition annule et remplace la première édition parue en 1983. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - La structure des articles a été modifiée du point de vue d’une procédure d’essai en laboratoire. La nouvelle séquence est la suivante: spécification du banc d’essai , procédure générale d’essai, et procédure spécifique relative à chaque caractéristique opérationnelle. - Un nouvel article a été ajouté pour présenter l’essai de bande noire pour la caractérisation des nuances de balais pour machines à courant continu.

Električni rotacijski stroji - Preskusne metode in aparati za merjenje obratovalnih lastnosti ščetk (IEC 60773:2021)

General Information

Status
Published
Public Enquiry End Date
19-Jan-2020
Publication Date
07-Sep-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Jun-2021
Due Date
06-Aug-2021
Completion Date
08-Sep-2021

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SLOVENSKI STANDARD
SIST EN IEC 60773:2021
01-oktober-2021

Električni rotacijski stroji - Preskusne metode in aparati za merjenje obratovalnih

lastnosti ščetk (IEC 60773:2021)

Rotating electrical machines - Test methods and apparatus for the measurement of the

operational characteristics of brushes (IEC 60773:2021)

Drehende elektrische Maschinen - Prüfverfahren und -einrichtungen für die Messung der

Betriebseigenschaften von Kohlebürsten (IEC 60773:2021)

Machines électriques tournantes - Méthodes d'essai et appareils pour le mesurage des

caractéristiques opérationnelles des balais (IEC 60773:2021)
Ta slovenski standard je istoveten z: EN IEC 60773:2021
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
SIST EN IEC 60773:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 60773:2021
---------------------- Page: 2 ----------------------
SIST EN IEC 60773:2021
EUROPEAN STANDARD EN IEC 60773
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2021
ICS 29.160.10
English Version
Rotating electrical machines - Test methods and apparatus for
the measurement of the operational characteristics of brushes
(IEC 60773:2021)

Machines électriques tournantes - Méthodes d'essai et Drehende elektrische Maschinen - Prüfverfahren und -

appareils pour le mesurage des caractéristiques einrichtungen für die Messung der Betriebseigenschaften

opérationnelles des balais von Kohlebürsten
(IEC 60773:2021) (IEC 60773:2021)

This European Standard was approved by CENELEC on 2021-05-12. 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,

Turkey 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

© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60773:2021 E
---------------------- Page: 3 ----------------------
SIST EN IEC 60773:2021
EN IEC 60773:2021 (E)
European foreword

The text of document 2/2045/FDIS, future edition 2 of IEC 60773, prepared by IEC/TC 2 "Rotating

machinery" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN IEC 60773:2021.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2022-02-12

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2024-05-12

document have to be withdrawn

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.

Endorsement notice

The text of the International Standard IEC 60773:2021 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 60027-4:2006 NOTE Harmonized as EN 60027-4:2007 (not modified)
IEC 60034-1:2017 NOTE Harmonized as EN 60034-1:— (modified)
ISO 4287:1997 NOTE Harmonized as EN ISO 4287:1998 (not modified)
ISO 4287:1997/A1:2009 NOTE Harmonized as EN ISO 4287:1998/A1:2009 (not modified)
To be published. Stage at the time of publication: FprEN 60034-1:2017/prAA.
---------------------- Page: 4 ----------------------
SIST EN IEC 60773:2021
EN IEC 60773:2021 (E)
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 60034-19 2014 Rotating electrical machines - Part 19: EN 60034-19 2014
Specific test methods for d.c. machines on
conventional and rectifier-fed supplies
IEC 60136 - Dimensions of brushes and brush-holders - -
for electrical machinery
IEC 60276 2018 Carbon brushes, brush holders, EN IEC 60276 2019
commutators and slip-rings - Definitions and
nomenclature
IEC 60356 - Dimensions for commutators and slip-rings - -
IEC 60584-1 2013 Thermocouples - Part 1: EMF specifications EN 60584-1 2013
and tolerances
IEC 60751 2008 Industrial platinum resistance thermometers EN 60751 2008
and platinum temperature sensors
IEC/TR 61015 - Brush-holders for electrical machines. - -
Guide to the measurement of the static
thrust applied to brushes
ISO 1190-1 1982 Copper and copper alloys; Code of - -
designation; Part 1: Designation of
materials
ISO 3274 1996 Geometrical Product Specifications (GPS) - EN ISO 3274 1997
Surface texture: Profile method - Nominal
characteristics of contact (stylus)
instruments
ISO 15510 2014 Stainless steels - Chemical composition - -
---------------------- Page: 5 ----------------------
SIST EN IEC 60773:2021
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SIST EN IEC 60773:2021
IEC 60773
Edition 2.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Rotating electrical machines – Test methods and apparatus for the
measurement of the operational characteristics of brushes
Machines électriques tournantes – Méthodes d'essai et appareils pour le
mesurage des caractéristiques opérationnelles des balais
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.160.10 ISBN 978-2-8322-9656-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN IEC 60773:2021
– 2 – IEC 60773:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 6

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms, definitions, symbols and abbreviated terms .......................................................... 8

3.1 Terms and definitions .............................................................................................. 9

3.2 Symbols ................................................................................................................ 15

3.2.1 Symbols and units ......................................................................................... 15

3.2.2 Subscripts ..................................................................................................... 16

3.3 Abbreviated terms ................................................................................................. 17

4 Test rig specification...................................................................................................... 18

4.1 Common specification ........................................................................................... 18

4.1.1 General ......................................................................................................... 18

4.1.2 Rings ............................................................................................................. 18

4.1.3 Brushes ......................................................................................................... 19

4.1.4 Brush holders ................................................................................................ 19

4.1.5 Power supply ................................................................................................. 21

4.1.6 Instrumentation .............................................................................................. 21

4.2 Test rig specification for commutators ................................................................... 31

4.2.1 General ......................................................................................................... 31

4.2.2 Test rings ...................................................................................................... 31

4.2.3 Brushes arrangement .................................................................................... 34

4.2.4 Special brush for voltage drop measurement ................................................. 35

4.3 Test rig specification for slip rings ......................................................................... 36

4.3.1 General ......................................................................................................... 36

4.3.2 Ring............................................................................................................... 36

4.3.3 Brushes ......................................................................................................... 38

4.3.4 Configuration for DC and AC operation .......................................................... 38

5 Test schedule and operating conditions ......................................................................... 40

5.1 General ................................................................................................................. 40

5.2 Environmental conditions ...................................................................................... 41

5.2.1 Laboratory environment ................................................................................. 41

5.2.2 Ambient air temperature and ring surface temperature ................................... 41

5.2.3 Ambient humidity ........................................................................................... 41

5.3 Operating conditions ............................................................................................. 41

5.4 Test preparation and inspection ............................................................................ 42

5.4.1 General ......................................................................................................... 42

5.4.2 Test rig .......................................................................................................... 42

5.4.3 Brush-holders ................................................................................................ 42

5.4.4 Test brushes .................................................................................................. 42

5.4.5 Ring roughness ............................................................................................. 42

5.4.6 Brush bedding ............................................................................................... 43

5.4.7 Brushes measurement ................................................................................... 43

5.5 Test sequence ...................................................................................................... 43

5.5.1 Test starting .................................................................................................. 43

5.5.2 Test duration ................................................................................................. 43

5.6 Measurements and observations ........................................................................... 43

5.6.1 General ......................................................................................................... 43

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SIST EN IEC 60773:2021
IEC 60773:2021 © IEC 2021 – 3 –

5.6.2 Interval between measurements .................................................................... 44

5.6.3 Before starting a test sequence ..................................................................... 44

5.6.4 Measurements during a test sequence ........................................................... 45

5.6.5 Measurements after a test sequence ............................................................. 45

6 Determination of friction coefficient ................................................................................ 45

6.1 General ................................................................................................................. 45

6.2 Test conditions ..................................................................................................... 46

6.3 Measurements ...................................................................................................... 46

6.3.1 General ......................................................................................................... 46

6.3.2 Test rig arrangement of Method a) ................................................................. 46

6.3.3 Test rig arrangement of Method b) ................................................................. 46

6.4 Calculation of friction coefficient ........................................................................... 46

6.4.1 Test rig arrangement of Method a) ................................................................. 46

6.4.2 Test rig arrangement of Method b) ................................................................. 47

6.5 Report................................................................................................................... 47

7 Determination of voltage drop ........................................................................................ 48

7.1 General ................................................................................................................. 48

7.2 Test conditions ..................................................................................................... 49

7.3 Measurements ...................................................................................................... 49

7.3.1 General ......................................................................................................... 49

7.3.2 Brush total voltage drop U ........................................................................... 49

7.3.3 Brush contact voltage drop U ....................................................................... 49

7.4 Calculation ............................................................................................................ 50

7.4.1 Brush total voltage drop U ........................................................................... 50

7.4.2 Brush contact voltage drop U ....................................................................... 50

7.5 Report................................................................................................................... 51

8 Determination of brush wear .......................................................................................... 52

8.1 General ................................................................................................................. 52

8.2 Test conditions ..................................................................................................... 52

8.3 Measurements ...................................................................................................... 52

8.4 Calculation of brush wear...................................................................................... 53

8.5 Report................................................................................................................... 54

9 Determination of commutation ability of brush grades by a specific black-band test

on a DC machine ........................................................................................................... 54

9.1 General ................................................................................................................. 54

9.2 Set-up ................................................................................................................... 55

9.3 Test procedure ...................................................................................................... 58

9.3.1 Preparation of the test ................................................................................... 58

9.3.2 Operating conditions and test sequence ........................................................ 58

9.4 Black-band graph .................................................................................................. 59

9.5 Interpretation ........................................................................................................ 60

9.5.1 General ......................................................................................................... 60

9.5.2 Influence of commutator skin thickness on the black-band zone .................... 61

9.5.3 Influence of brush contact resistance ............................................................. 62

9.5.4 Estimation of mechanical contact stability deviation by comparing the

black-band figures before and after longtime critical operation ....................... 64

Annex A (informative) Additional information for friction coefficient measurement ................ 67

A.1 Details of calculation of friction coefficient by using method a) of 4.1.6.1.2 ........... 67

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SIST EN IEC 60773:2021
– 4 – IEC 60773:2021 © IEC 2021
A.2 Adjustment of strain sensor for calculation of friction coefficient by using

method b) of 4.1.6.1.3 ........................................................................................... 68

A.2.1 General ......................................................................................................... 68

A.2.2 Correlation between output voltage and load ................................................. 68

A.2.3 Correlation between friction coefficient and load ............................................ 68

Annex B (informative) Black-band zone deviation cases ...................................................... 71

B.1 Black-band zone in case of limited contact area .................................................... 71

B.2 Influence of brush mechanical contact instability of brush chattering on the

black-band zone ................................................................................................... 72

B.3 Black-band zone hysteresis between increased I and decreased I .................... 73

a a

Annex C (informative) Test report example .......................................................................... 75

Bibliography .......................................................................................................................... 77

Figure 1 – Profile and determination of height of profile elements ........................................... 9

Figure 2 – Forces acting on a brush ...................................................................................... 12

Figure 3 – Voltage drops in a brush when in operation .......................................................... 12

Figure 4 – Brush holder configuration ................................................................................... 20

Figure 5 – Measurement of the mechanical torque by Method a) ........................................... 22

Figure 6 – Brush test machine for Method b) ......................................................................... 23

Figure 7 – Test rig arrangement with a load cell .................................................................... 24

Figure 8 – Brush contact probe application point for U ........................................................ 27

Figure 9 – Thermocouples insertion position ......................................................................... 28

Figure 10 – Evaluation of contact temperature θ by interpolation ......................................... 29

Figure 11 – Illustration of bar grooves dimensions and preparation ....................................... 32

Figure 12 – Brush covering ................................................................................................... 34

Figure 13 – Brushes configuration ........................................................................................ 35

Figure 14 – Control brush arrangement ................................................................................. 36

Figure 15 – Characteristics of grooves .................................................................................. 37

Figure 16 – Test rig arrangement for DC operation with 2 brushes per polarity ..................... 39

Figure 17 – Test rig arrangement for AC operation with 2 brushes ........................................ 40

Figure 18 – Example of friction coefficient µ graph as a function of peripheral speed ν ....... 48

Figure 19 – Example of brush total voltage drop U graph as a function of

current density J ................................................................................................................. 52

Figure 20 – Example of brush wear rate WR of brushes during the test for a test rig

with 4 brushes ...................................................................................................................... 53

Figure 21 – Black-band test circuit configuration using DC generator and resistance

load 56

Figure 22 – Black-band test circuit configuration for Brondell’s loading-back method ............ 57

Figure 23 – Determination of black-band zone for a specified constant speed of

rotation ................................................................................................................................. 60

Figure 24 – Influence of commutator film thickness on the black-band zone .......................... 62

Figure 25 – Comparison of black-bands for a high contact resistance brush and a low

contact resistance brush in case of a motor .......................................................................... 63

Figure 26 – Comparison of black-bands for a high contact resistance brush and a low

contact resistance brush in case of a generator .................................................................... 64

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SIST EN IEC 60773:2021
IEC 60773:2021 © IEC 2021 – 5 –

Figure 27 – Black-band figure deviation of before and after the critical operation of

repetitive peak load application of 225 %, for a "strong" grade .............................................. 65

Figure 28 – Black-band figure deviation of before and after the critical operation of

repetitive peak load application of 225 %, for a "weak" grade ............................................... 66

Figure A.1 – Correlation of load cell output voltage U with mass m ..................................... 68

Figure A.2 – Example of correlation between load and friction coefficient µ .......................... 69

Figure B.1 – Limited contact area and reduction of tangential dimension at contact .............. 71

Figure B.2 – Black-band zone in case of a limited contact area ............................................. 72

Figure B.3 – Influence of brush mechanical contact instability of brush chattering on

the black-band zone.............................................................................................................. 73

Figure B.4 – Black-band zone hysteresis between increasing I and decreasing I ....... 74

arm arm

Table 1 – Dimensions of test brushes ................................................................................... 19

Table 2 – Test conditions ...................................................................................................... 42

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SIST EN IEC 60773:2021
– 6 – IEC 60773:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –
TEST METHODS AND APPARATUS FOR THE MEASUREMENT
OF THE OPERATIONAL CHARACTERISTICS OF BRUSHES
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

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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

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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 60773 has been prepared by IEC technical committee 2: Rotating

machinery.

This second edition cancels and replaces the first edition published in 1983. It constitutes a

technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

– The clause structure has been modified on the view point of a laboratory testing procedure.

The new sequence is as follows: test rig specification (Clause 4), general testing procedure

(Clause 5), and specific procedure for each operational characteristic (Clauses 6 to 8).

– A new Clause 9 has been added to introduce the black-band test for the characterisation of

the brush grades for DC machine
...

SLOVENSKI STANDARD
oSIST prEN IEC 60773:2020
01-januar-2020

Rotacijski stroji - Preskusne metode in aparati za merjenje obratovalnih lastnosti

ščetk
Rotating machinery - Test methods and apparatus for the measurement of the
operational characteristics of brushes

Méthodes d'essais et appareils pour la mesure des propriétés opérationnelles des balais

Ta slovenski standard je istoveten z: prEN IEC 60773:2019
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
oSIST prEN IEC 60773:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN IEC 60773:2020
---------------------- Page: 2 ----------------------
oSIST prEN IEC 60773:2020
2/1967/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60773 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2019-11-01 2020-01-24
SUPERSEDES DOCUMENTS:
2/1921/CD, 2/1946/CC
IEC TC 2 : ROTATING MACHINERY
SECRETARIAT: SECRETARY:
United Kingdom Mr Charles Whitlock
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if any, in
this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.
TITLE:

Rotating machinery – Test methods and apparatus for the measurement of the operational characteristics of

brushes
PROPOSED STABILITY DATE: 2022
NOTE FROM TC/SC OFFICERS:

Copyright © 2019 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to download this

electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.

You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without

permission in writing from IEC.
---------------------- Page: 3 ----------------------
oSIST prEN IEC 60773:2020
– 2 – IEC CDV 60773  IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 6

PREFACE ............................................................................................................................... 6

1 Scope .............................................................................................................................. 8

2 Normative References ..................................................................................................... 8

3 Terms, definitions, symbols and abbreviated terms .......................................................... 9

3.1 Terms and definitions.............................................................................................. 9

3.2 Symbols ................................................................................................................ 15

3.2.1 Symbols and units ......................................................................................... 15

3.2.2 Subscripts ..................................................................................................... 17

3.3 Abbreviated terms ................................................................................................. 18

4 Test rig specification ..................................................................................................... 19

4.1 Common specification ........................................................................................... 19

4.1.1 General ......................................................................................................... 19

4.1.2 Rings ............................................................................................................. 19

4.1.3 Brushes ......................................................................................................... 20

4.1.4 Brush holders ................................................................................................ 21

4.1.5 Power supply ................................................................................................. 22

4.1.6 Instrumentation .............................................................................................. 23

4.2 Test rig specification for Commutators .................................................................. 33

4.2.1 General ......................................................................................................... 33

4.2.2 Test rings ...................................................................................................... 33

4.2.3 Brushes arrangement .................................................................................... 37

4.2.4 Special brush for voltage drop measurement ................................................. 38

4.3 Test rig specification for slip rings ......................................................................... 39

4.3.1 General ......................................................................................................... 39

4.3.2 Ring .............................................................................................................. 39

4.3.3 Brushes ......................................................................................................... 41

4.3.4 Configuration for DC and AC operation .......................................................... 41

5 Test schedule and operating conditions ......................................................................... 43

5.1 General ................................................................................................................. 43

5.2 Environmental conditions ...................................................................................... 44

5.2.1 Laboratory environment ................................................................................. 44

5.2.2 Ambient air temperature and ring surface temperature................................... 44

5.2.3 Ambient humidity ........................................................................................... 44

5.3 Operating conditions ............................................................................................. 44

5.4 Test preparation and inspection ............................................................................ 45

5.4.1 Test rig .......................................................................................................... 45

5.4.2 Brush-holders ................................................................................................ 45

5.4.3 Test brushes.................................................................................................. 45

5.4.4 Test ring roughness ....................................................................................... 45

5.4.5 Brush bedding ............................................................................................... 46

5.4.6 Brushes measurement ................................................................................... 46

5.5 Test sequence ...................................................................................................... 46

5.5.1 Test starting .................................................................................................. 46

5.5.2 Test duration ................................................................................................. 46

5.6 Measurements and observations ........................................................................... 47

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oSIST prEN IEC 60773:2020
IEC CDV 60773  IEC 2019 – 3 –

5.6.1 General ......................................................................................................... 47

5.6.2 Interval between measurements .................................................................... 47

5.6.3 Before starting a test sequence ..................................................................... 47

5.6.4 Measurements during a test sequence ........................................................... 48

5.6.5 Measurements after a test sequence ............................................................. 48

6 Determination of friction coefficient ................................................................................ 48

6.1 General ................................................................................................................. 48

6.2 Test conditions ..................................................................................................... 49

6.3 Measurements ...................................................................................................... 49

6.3.1 General ......................................................................................................... 49

6.3.2 Test rig arrangement of Method a) ................................................................. 49

6.3.3 Test rig arrangement of Method b) ................................................................. 49

6.4 Calculation of friction coefficient ........................................................................... 49

6.4.1 Test rig arrangement of Method a) ................................................................. 49

6.4.2 Test rig arrangement of Method b) ................................................................. 50

6.5 Report .................................................................................................................. 50

7 Determination of voltage drop ........................................................................................ 51

7.1 General ................................................................................................................. 51

7.2 Test conditions ..................................................................................................... 52

7.3 Measurements ...................................................................................................... 52

7.3.1 General ......................................................................................................... 52

7.3.2 Brush total voltage drop U ........................................................................... 52

7.3.3 Brush contact voltage drop U ....................................................................... 52

7.4 Calculation ............................................................................................................ 53

7.4.1 Brush total voltage drop U ........................................................................... 53

7.4.2 Brush contact voltage drop U ....................................................................... 53

7.5 Report .................................................................................................................. 54

8 Determination of brush wear .......................................................................................... 55

8.1 General ................................................................................................................. 55

8.2 Test conditions ..................................................................................................... 55

8.3 Measurements ...................................................................................................... 55

8.4 Calculation of brush wear ..................................................................................... 56

8.5 Report .................................................................................................................. 57

9 Determination of commutation ability of brush grades by a specific black band test

on a D.C. machine ......................................................................................................... 57

9.1 General ................................................................................................................. 57

9.2 Set-up ................................................................................................................... 58

9.3 Test procedure...................................................................................................... 60

9.3.1 Preparation of the test ................................................................................... 60

9.3.2 Operating conditions and test sequence ........................................................ 60

9.4 Black band graph .................................................................................................. 61

9.5 Interpretation ........................................................................................................ 62

9.5.1 General ......................................................................................................... 62

9.5.2 Influence of commutator skin thickness on the black-band zone .................... 63

9.5.3 Influence of brush contact resistance ............................................................. 64

9.5.4 Estimation of mechanical contact stability deviation by comparing the

black band figures before and after long time critical operation ...................... 66

Annex A (Informative) Additives for friction coefficient measurement .................................. 68

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A.1 Details of calculation of friction coefficient by using method a) .............................. 68

A.2 Adjustment of strain sensor for calculation of friction coefficient by using

method b) ............................................................................................................. 68

A.2.1 Correlation between output voltage and load: ................................................ 69

A.2.2 Correlation between friction coefficient and load: ........................................... 69

Annex B (Informative) Black band zone deviation cases ...................................................... 72

B.1 Black-band zone in case of limited contact area .................................................... 72

B.2 Influence of brush mechanical contact instability of brush chattering on the

black-band zone ................................................................................................... 73

B.3 Black-band zone hysteresis between increased I and decreased I .................... 74

a a

Annex C (informative) Test report example .......................................................................... 76

Figure 1 – Profile and determination of height of profile elements ......................................... 10

Figure 2 – Forces acting on a brush ...................................................................................... 12

Figure 3 – Voltage drops in a brush when in operation .......................................................... 13

Figure 4 –Brush holder configuration .................................................................................... 22

Figure 5 – Measurement of the mechanical torque by Method a) ........................................... 24

Figure 6 – Brush test machine for Method b) ......................................................................... 25

Figure 7 – Test rig arrangement with a load cell .................................................................... 26

Figure 8 – Brush contact probe application point for U ........................................................ 29

Figure 9 – Thermocouples insertion position ......................................................................... 30

Figure 10 – Evaluation of contact temperature θ by interpolation ......................................... 31

Figure 11 – Illustration of bar grooves dimensions and preparation ....................................... 34

Figure 12 – Brush covering ................................................................................................... 37

Figure 13 – Brushes configuration ........................................................................................ 38

Figure 14 – Control brush arrangement ................................................................................. 39

Figure 15 – Characteritics of grooves ................................................................................... 40

Figure 16 – Test rig arrangement for DC operation with 2 brushes per polarity ..................... 42

Figure 17 – Test rig arrangement for AC operation with 2 brushes ........................................ 43

Figure 18 – Example of friction coefficient µ graph as a function of peripheral speed ν ........ 51

Figure 19 –Example of brush total voltage drop U graph as a function of current

.............................................................................................................................. 55

density J

Figure 20 – Example of brush wear rate WR of brushes during the test for a test rig

with 4 brushes ...................................................................................................................... 56

Figure 21 – Black-band test circuit configuration with using dc generator and

resistance load ..................................................................................................................... 58

Figure 22 – Black-band test circuit configuration for Brondell’s loading-back method ............ 59

Figure 23 – Determination of Black band zone for a specified constant speed of

rotation ................................................................................................................................. 62

Figure 24 – Influence of commutator film thickness on the black-band zone .......................... 64

Figure 25 – Comparison of black bands for a high contact resistance brush and a low

contact resistance brush in case of a motor .......................................................................... 65

Figure 26 – Comparison of black bands for a high contact resistance brush and a low

contact resistance brush in case of a generator .................................................................... 65

Figure 27 – Black-band figure deviation of before and after the critical operation of

repetitive peak load application of 225 %, for a "strong" grade .............................................. 66

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Figure 28 –Black-band figure deviation of before and after the critical operation of

repetitive peak load application of 225 %, for a "week" grade ............................................... 67

Figure A.1 – Correlation of load cell output voltage U with mass m ..................................... 69

Figure A.2 – Example of correlation between load and friction coefficient µ .......................... 70

Figure B.1 – Limited contact area and reduction of tangential dimension at contact .............. 72

Figure B.2 – Black-band zone in case of a limited contact area ............................................. 73

Figure B.3 – Influence of brush mechanical contact instability of brush chattering on

the black-band zone ............................................................................................................. 74

Figure B.4 – Black-band zone hysteresis between increasing I and decreasing I ....... 75

arm arm

Table 1 – Subscripts ............................................................................................................. 17

Table 2 – Dimensions of test brushes ................................................................................... 21

Table 3 – Test conditions ...................................................................................................... 45

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1 INTERNATIONAL ELECTROTECHNICAL COMMISSION
2 ____________
4 ROTATING ELECTRICAL MACHINES –
6 TEST METHODS AND APPARATUS FOR THE MEASUREMENT
7 OF THE OPERATIONAL CHARACTERISTICS OF BRUSHES
9 FOREWORD

10 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

11 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

12 international co-operation on all questions concerning standardization in the electrical and electronic fields. To

13 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

14 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

15 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

16 in the subject dealt with may participate in this preparatory work. International, governmental and non-

17 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

18 with the International Organization for Standardization (ISO) in accordance with conditions determined by

19 agreement between the two organizations.

20 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

21 consensus of opinion on the relevant subjects since each technical committee has representation from all

22 interested IEC National Committees.

23 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

24 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

25 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

26 misinterpretation by any end user.

27 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

28 transparently to the maximum extent possible in their national and regional publications. Any divergence

29 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

30 the latter.

31 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

32 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

33 services carried out by independent certification bodies.

34 6) All users should ensure that they have the latest edition of this publication.

35 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

36 members of its technical committees and IEC National Committees for any personal injury, property damage or

37 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

38 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

39 Publications.

40 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

41 indispensable for the correct application of this publication.

42 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

43 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

45 PREFACE

46 International standard IEC 60773:XXX has been prepared by IEC subcommittee MT14:

47 Brushes and Brush-Holders for electrical machinery, under the responsibility of IEC technical

48 committee 2:Rotating Machinery.

49 This second edition cancels and replaces the first edition published in 1983. It constitutes a

50 technical revision.

51 All changes and additions are too numerous to be listed. However main changes can be

52 summarized as follow:

53 – The layout has been updated and adjusted to comply with the ISO/IEC Directives, Part 2.

54 – The clause structure has been modified on the view point of a laboratory testing

55 procedure. The new sequence is as follows: test rig specification (clause 4), general

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56 testing procedure (clause 5), and each operational characteristic procedure (clauses 6 to

57 8).

58 – A new clause 9 has been added to introduce the black band test for the characterisation of

59 the brush grades for DC machines.
60 The text of this standard is based on the following documents:
FDIS Report on voting
1/####/FDIS 1/####/RVD

61 Full information on the voting for the approval of this standard can be found in the report on

62 voting indicated in the above table.

63 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

64 The National Committees are requested to note that for this document the stability date

65 is 2029.

66 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE

67 DELETED AT THE PUBLICATION STAGE.
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71 ROTATING ELECTRICAL MACHINES –
73 TEST METHODS AND APPARATUS FOR THE MEASUREMENT
74 OF THE OPERATIONAL CHARACTERISTICS OF BRUSHES
78 1 Scope

79 This standard applies to test methods for the measurement of the operational characteristics

80 of brushes designed to operate on commutating and slip ring machines under specified test

81 conditions.

82 By extension some tests may be relevant for other kind of sliding electrical contacts for

83 electrical appliances.
84 2 Normative References

85 The following documents are referred to in the text in such a way that some or all of their

86 content constitutes requirements of this document. For dated references, only the edition

87 cited applies. For undated references, the latest edition of the referenced document (including

88 any amendments) applies.

89 IEC 60027-1, Letter symbols to be used in electrical technology − Part 1: General

90 IEC 60027-4, Letter symbols to be used in electrical technology − Part 4: Rotating electrical

91 machines

92 IEC 60034-19:2014, Rotating electrical machines - Part 19: Specific test methods for d.c.

93 machines on conventional and rectifier-fed supplies

94 IEC 60050-411, International Electrotechnical Vocabulary - Chapter 411: Rotating machinery

95 IEC 60136, Dimensions of Brushes and Brush-holders for Electrical Machinery

96 IEC 60276:2018, Definitions and nomenclature for brushes, brush-holders, commutators and

97 slip rings

98 IEC 60560, Definitions and terminology of brush-holders for electrical machines

99 IEC 60584-1:2013, Thermocouples – Part 1: EMF specifications and tolerances

100 IEC 60751:2008, Industrial platinum resistance thermometers and platinum temperature

101 sensors

102 IEC/TR 61015, Brush-holders for electrical machines. Guide to the measurement of the static

103 thrust applied to brushes

104 ISO 1190-1:1982, Copper and copper alloys – code of designation – Part 1: Designation of

105 materials

106 ISO 3274:1996, Geometrical Product Specifications (GPS) - Surface texture: Profile method -

107 Nominal characteristics of contact (stylus) instruments
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108 ISO 4287:1997/Amd 1:2009, Geometrical Product Specifications (GPS) - Surface texture:

109 Profile method - Terms, definitions and surface texture parameters - AMENDMENT 1: Peak

110 count number
111 ISO 15510, Stainless steel – Chemical composition
112 3 Terms, definitions, symbols and abbreviated terms

113 For the purposes of this document, the terms and definitions given in standards specified in

114 clause 2, some of which are repeated here for convenience, and the following apply.

115 ISO and IEC maintain terminological databases for use in standardization at the following

116 addresses:
117 • IEC Electropedia: available at http://www.electropedia.org/
118 • ISO Online browsing platform: available at http://www.iso.org/obp
119 3.1 Terms and definitions
120 3.1.1
121 run-out
122 runout

123 an inaccuracy of the rotating system, measured on the surface of the ring while turning

124 Note 1 to entry: This includes out-of-round (that is, lacking sufficient roundness); eccentricity (that is, lacking

125 sufficient concentricity); or axial bending (regardless of whether the surfaces are perfectly round and concentric at

126 every cross-sectional point).
127 3.1.2
128 roughness
129 Ra

130 arithmetic mean of the absolute ordinate value Z(x) of a profile within a sampling length l

Ra= � |Z(x)| dx
131 Example: Figure 1 below shows an example of profile.
132
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133
134
135 Key:

editorial note 1 for IEC: figure, key and title are expected to be only on one page

136 Zt profile ele
...

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