SIST EN IEC 60773:2021

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.

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oSIST prEN IEC 60773:2020

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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.

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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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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
B
7.3.3 Brush contact voltage drop U . 52
c
7.4 Calculation . 53
7.4.1 Brush total voltage drop U . 53
B
7.4.2 Brush contact voltage drop U . 53
c
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
c
Figure 9 – Thermocouples insertion position . 30
Figure 10 – Evaluation of contact temperature θ by interpolation . 31
c
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
p
Figure 19 –Example of brush total voltage drop U graph as a function of current
B
. 55
density J
B
Figure 20 – Example of brush wear rate WR of brushes during the test for a test rig
i
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
lc
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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oSIST prEN IEC 60773:2020
– 6 – IEC CDV 60773  IEC 2019
1 INTERNATIONAL ELECTROTECHNICAL COMMISSION
2 ____________
3
4 ROTATING ELECTRICAL MACHINES –
5
6 TEST METHODS AND APPARATUS FOR THE MEASUREMENT
7 OF THE OPERATIONAL CHARACTERISTICS OF BRUSHES
8
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.
44
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.
68
69
70

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71 ROTATING ELECTRICAL MACHINES –
72
73 TEST METHODS AND APPARATUS FOR THE MEASUREMENT
74 OF THE OPERATIONAL CHARACTERISTICS OF BRUSHES
75
76
77
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
l
1
Ra= � |Z(x)| dx
l
0
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
...