prEN IEC 60034-8:2025
(Main)Rotating electrical machines - Part 8: Terminal markings and direction of rotation
Rotating electrical machines - Part 8: Terminal markings and direction of rotation
Drehende elektrische Maschinen - Teil 8: Anschlussbezeichnungen und Drehsinn
Machines électriques tournantes - Partie 8: Marquages d'extrémité et sens de rotation
Električni rotacijski stroji - 8. del: Oznake priključkov in smeri vrtenja (rotacije)
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Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2025
Električni rotacijski stroji - 8. del: Oznake priključkov in smeri vrtenja (rotacije)
Rotating electrical machines - Part 8: Terminal markings and direction of rotation
Drehende elektrische Maschinen - Teil 8: Anschlussbezeichnungen und Drehsinn
Machines électriques tournantes - Partie 8: Marquages d'extrémité et sens de rotation
Ta slovenski standard je istoveten z: prEN IEC 60034-8:2025
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
2/2246/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60034-8 ED4
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-06-20 2025-09-12
SUPERSEDES DOCUMENTS:
2/2202/CD, 2/2241A/CC
IEC TC 2 : ROTATING MACHINERY
SECRETARIAT: SECRETARY:
United Kingdom Mr Charles Whitlock
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
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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
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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.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Rotating electrical machines - Part 8: Terminal markings and direction of rotation
PROPOSED STABILITY DATE: 2027
NOTE FROM TC/SC OFFICERS:
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
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IEC 60034-8 ED4 © IEC 2025 2
1 CONTENTS
2 FOREWORD . 5
3 INTRODUCTION . 7
4 1 Scope . 8
5 2 Normative references . 8
6 3 Terms and definitions . 8
7 4 Symbols . 11
8 4.1 General . 11
9 4.2 DC and single-phase commutator machines . 11
10 4.3 AC machines without commutators . 11
11 4.4 Auxiliary devices . 11
12 5 Direction of rotation . 12
13 6 Rules for terminal markings . 12
14 6.1 General . 12
15 6.2 Suffixes . 14
16 6.3 Prefixes . 15
17 6.4 Winding identification for categories of machines . 15
18 6.5 Synchronous machines . 16
19 6.6 DC machines . Error! Bookmark not defined.
20 6.7 Relation between terminal markings and direction of rotation . 16
21 6.8 Terminal marking figures . 17
22 7 Auxiliary terminal marking rules . 23
23 7.1 General . 23
24 7.2 Marking . 23
26 Annex A (normative) Connection diagrams for common applications . 26
28 Figure 1 – Single three-phase winding, three elements, open connection, six terminals . 18
29 Figure 2 – Single three-phase winding, delta connection, three terminals . 19
30 Figure 3 – Single three-phase winding, internal star connection with neutral conductor,
31 four terminals . 19
32 Figure 4 – Single three-phase winding, two elements per phase, open connection,
33 twelve terminals . 19
34 Figure 5 – Single three-phase winding, four elements per phase, open connection,
35 twenty-four terminals . 19
36 Figure 6 – Single three-phase winding, two elements per phase with four tapping
37 points per element, open connection, thirty-six terminals . 20
38 Figure 7 – Two separate three-phase windings with two independent functions, two
39 elements per phase, open connection, twenty-four terminals . 20
40 Figure 8 – Two elements, internal connection, three terminals . 20
41 Figure 9 – Single three-phase winding, star connection, duplicate terminals for
42 alternate connection, six terminals . 20
43 Figure 10 – Single three-phase winding, star connection, parallel terminals for shared
44 current, six terminals . 21
IEC 60034-8 ED4 © IEC 2025 3
46 Figure 11 – Three-phase wound-rotor, star connections with neutral conductors, eight
47 terminals . 21
48 Figure 12 – Main and auxiliary winding, two elements . 21
49 Figure 13 – Single-phase auxiliary winding, integrally connected capacitor, one
50 element . 21
51 Figure 14 – Single-phase main winding, integrally connected thermal protector, one
52 element . 21
53 Figure 15 – Six-phase winding, open connection, six elements . 21
54 Figure 16 – Armature winding, one element . 22
55 Figure 17 – Commutating winding, one and two elements . 22
56 Figure 18 – Compensating winding, one and two elements . 22
57 Figure 19 – Series winding, one element, two tappings . 22
58 Figure 20 – Shunt excitation winding, one element . 22
59 Figure 21 – Separately excited excitation winding, one and two elements . 22
60 Figure 22 – Direct-axis auxiliary winding, one element . 22
61 Figure 23 – Quadrature-axis auxiliary winding, one element . 22
62 Figure 24 – Armature winding with commutating and compensating windings, one
63 element . 22
64 Figure 25 – Single-phase, single voltage . 23
65 Figure 26 – Single-phase, dual voltage . 24
66 Figure 27 – Three-phase, single voltage . 24
67 Figure 28 – Three-phase, dual voltage . 24
68 Figure 29 – Two-lead devices (except type R) . 24
69 Figure 31 – Three-lead devices of type R . 25
70 Figure 32 – Four-lead devices of type R . 25
71 Figure 33 – Switch connections . 25
72 Figure A.1 – Delta connection . 26
73 Figure A.2 – Star connection – with or without neutral . 26
74 Figure A.3 – Dual voltage, six terminals (1:√3) . 26
75 Figure A.4 – Star-connected, dual voltage, nine terminals (1:2) . 27
76 Figure A.5 – Delta-connected, dual voltage, nine terminals (1:2) . 27
77 Figure A.6 – Star-delta, single voltage, six terminals . 27
78 Figure A.7 – Star-delta, dual voltage, twelve terminals (1:2) . 28
79 Figure A.8 – Part-winding, single voltage, six terminals . 28
80 Figure A.9 – Part-winding, dual voltage, nine terminals (1:2). 29
81 Figure A.10 – Variable-torque, six terminals . 29
82 Figure A.11 – Variable-torque, dual-voltage (1:√3), nine terminals . 30
83 Figure A.12 – Constant-torque, six terminals . 31
84 Figure A.13 – Constant power, six terminals . 31
85 Figure A.14 – Variable-torque, six terminals . 32
86 Figure A.15 – Constant-torque, seven terminals . 32
87 Figure A.16 – Constant-power, seven terminals . 32
IEC 60034-8 ED4 © IEC 2025 4
89 Figure A.17 – Example of three-speed, constant torque motor using two separate
90 windings, ten terminals . 33
91 Figure A.18 – Example of three-speed motor using three separate windings, ten
92 terminals . 33
93 Figure A.19 – Example of four-speed, variable-torque motor using two separate
94 windings, twelve terminals . 34
95 Figure A.20 – Split-phase or capacitor-start reversible motor . 34
96 Figure A.21 – Reversible capacitor-start motor with four terminals with externally
97 connected capacitor . 35
98 Figure A.22 – Shunt motor or generator, four terminals . 35
99 Figure A.23 – Compound-motor or generator with compensating and commutating
100 windings, six terminals . 35
101 Figure A.24 – Series-wound motor, two terminals . 36
IEC 60034-8 ED4 © IEC 2025 5
103 INTERNATIONAL ELECTROTECHNICAL COMMISSION
104 ____________
106 ROTATING ELECTRICAL MACHINES –
108 Part 8: Terminal markings and direction of rotation
111 FOREWORD
112 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
113 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
114 co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
115 in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
116 Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
117 preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
118 may participate in this preparatory work. International, governmental and non-governmental organizations liaising
119 with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
120 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
121 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
122 consensus of opinion on the relevant subjects since each technical committee has representation from all
123 interested IEC National Committees.
124 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
125 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
126 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
127 misinterpretation by any end user.
128 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
129 transparently to the maximum extent possible in their national and regional publications. Any divergence between
130 any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
131 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
132 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
133 services carried out by independent certification bodies.
134 6) All users should ensure that they have the latest edition of this publication.
135 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
136 members of its technical committees and IEC National Committees for any personal injury, property damage or
137 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
138 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
139 Publications.
140 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
141 indispensable for the correct application of this publication.
142 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
143 rights. IEC shall not be held responsible for identifying any or all such patent rights.
145 This consolidated version of the official IEC Standard and its amendment has been
146 prepared for user convenience.
147 IEC 60034-8 edition 4 contains IEC 60034-8 edition 3.1 which contains the third edition
148 (2007-06) [documents 2/1434/FDIS and 2/1451/RVD] and its amendment 1 (2014-03)
149 [documents 2/1732/FDIS and 2/1743/RVD].
150 This Final version does not show where the technical content is modified by amendment
151 1. A separate Redline version with all changes highlighted is available in this publication.
IEC 60034-8 ED4 © IEC 2025 6
153 International Standard IEC 60034-8 has been prepared by IEC technical committee 2: Rotating
154 machinery.
155 The main change with respect to the previous edition is listed below:
156 - The inclusion of Turbine-type synchronous machines in the scope
157 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
158 A list of all the parts of the IEC 60034 series, under the general title Rotating electrical
159 machines, can be found on the IEC website.
160 The committee has decided that the contents of the base publication and its amendment will
161 remain unchanged until the stability date indicated on the IEC web site under
162 "http://webstore.iec.ch" in the data related to the specific publication. At this date, the
163 publication will be
164 • reconfirmed,
165 • withdrawn,
166 • replaced by a revised edition, or
167 • amended.
IEC 60034-8 ED4 © IEC 2025 7
172 INTRODUCTION
173 The revision of this part of IEC 60034 provides worldwide uniformity in the electrical
174 connections for rotating electrical machines and applies the recommendations of the basic
175 safety publication IEC 60445 in specifying marking requirements.
176 These standardized connections will then permit the safe interchange of electric machines with
177 their control and protective devices using standardized terminal markings.
178 Note: electrical connections of the machines are not the unique feature to be checked for safe
179 interchange.
IEC 60034-8 ED4 © IEC 2025 8
181 ROTATING ELECTRICAL MACHINES –
183 Part 8: Terminal markings and direction of rotation
187 1 Scope
188 This part of IEC 60034 applies to a.c. and d.c. machines and specifies
189 a) rules for the identification of winding connection points;
190 b) marking of winding terminals;
191 c) direction of rotation;
192 d) relationship between terminal markings and direction of rotation;
193 e) terminal marking of auxiliary devices;
194 f) connection diagrams of machines for common applications.
195 Turbine-type synchronous machines are excluded from this standard.
196 2 Normative references
197 The following referenced documents are indispensable for the application of this document. For
198 dated references, only the edition cited applies. For undated references, the latest edition of
199 the referenced document (including any amendments) applies.
200 IEC 60034-1, Rotating electrical machines – Part 1: Rating and performance
201 IEC 60034-3, Rotating electrical machines - Part 3: Specific requirements for synchronous
202 generators driven by steam turbines or combustion gas turbines and for synchronous
203 compensators
204 IEC 60034-33, Rotating electrical machines - Part 33: Synchronous hydrogenerators including
205 motor-generators - Specific requirements
206 IEC 60417-1, Graphical symbols for use on equipment – Part 1: Overview and application
207 IEC 60445, Basic and safety principles for man-machine interface, marking and identification –
208 Identification of equipment terminals and conductor terminations
209 3 Terms and definitions
210 For the purposes of this document, the terms and definitions given in IEC 60034-1 and the
211 following apply.
212 3.1
213 terminal marking
214 permanent identification of the external termination of winding leads or auxiliary leads at the
215 disposal of the user for connection of the machine to the supply or apparatus that indicates the
216 function of the termination
IEC 60034-8 ED4 © IEC 2025 9
217 3.2
218 connecting points
219 all current transfer points that are used to permanently interconnect winding or winding element
220 ends internally
IEC 60034-8 ED4 © IEC 2025 10
222 3.3
223 tapping points
224 intermediate connections to a portion of a winding element
225 3.4
226 winding leads
227 insulated conductors that make the electrical connection between a winding and its termination
228 3.5
229 winding
230 assembly of turns or coils having a defined function in an electrical rotating machine
231 [IEV 411-37-01]
232 3.6
233 winding phase
234 one or more winding elements associated with a particular phase
235 3.7
236 winding element
237 part of a winding, all the turns or coils in that part being permanently connected together
238 3.8
239 separate windings
240 two or more windings, each having a separate function, and not interconnected, used only
241 separately, whether fully or in part
242 3.9
243 multi-speed motor
244 motor, which can be operated at any one of two or more definite speeds
245 3.10
246 constant power
247 when a multi-speed motor provides approximately constant power over the speed range
248 3.11
249 constant torque
250 when a multi-speed motor provides approximately constant torque over the speed range
251 3.12
252 variable torque
253 when output torque of a multi-speed motor is proportional to approximately the square of the
254 speeds
255 3.13
256 phase sequence
257 order in which the voltages successively reach their maximum positive values between supply
258 conductors
IEC 60034-8 ED4 © IEC 2025 11
260 3.14
261 D-end
262 that end of the machine which accommodates the shaft end
263 [IEV 411-43-36]
264 NOTE For machines having two shaft ends, the D-end is the end
265 a) having the larger diameter;
266 b) opposite the external fan when the shaft ends are of the same diameter.
268 4 Symbols
269 4.1 General
L Supply conductor
PE Protective earthing terminal
User available terminal, marking mandatory
Internal connection point
(.) Internal terminal marking (showing element symbol), optional
[ . , . ] Grouping of user joined terminals
; Separation of terminals or groups of terminals
270 4.2 DC and single-phase commutator machines
A Armature winding
B Commutating winding
C Compensating winding
D Series excitation winding
E Shunt excitation winding
F Separately excited winding
H Direct-axis auxiliary winding
J Quadrature-axis auxiliary winding
271 4.3 AC machines without commutator
F DC excitation winding
K Secondary winding
L Secondary winding
M Secondary winding
N Star point (neutral conductor) of the primary winding
Q Star point (neutral conductor) of a secondary winding
U Primary winding
V Primary winding
W Primary winding
Z Auxiliary windings
272 NOTE The primary and secondary symbol allocations are irrespective of whether the primary winding is located in
273 the stator or rotor. Different symbols can be used as agreed between the Manufacturer and the Purchaser with special
274 attention to safety rules
275 4.4 .
IEC 60034-8 ED4 © IEC 2025 12
276 Auxiliary devices
BA AC brakes
BD DC brakes
BW Brush-wear detector
CA Capacitors
CT Current transformer
HE Heaters
LA Lightning arrestor
PT Potential transformer
R Resistance thermometers
SC Surge capacitor
SP Surge protectors
S Switches including plugging switches
TB Thermostats opening on increase of temperature
TC Thermocouples
TM Thermostats closing on increase of temperature
TN Thermistors, negative temperature coefficient
TP Thermistors, positive temperature coefficient
NOTE This table standardizes the most commonly used auxiliary devices. The
designation of other devices may be chosen by the manufacturer. Different symbols can
be used as agreed between the Manufacturer and the Purchaser, with special attention
to safety rules
277 5 Direction of rotation
278 The direction of rotation shall be that of the shaft observed when facing the D-end.
279 Synchronous generators and motor-generators in the scope of IEC 60034-3 or IEC 60034-33
280 shall have the direction of rotation as imposed by the prime mover being in turbine or motor
281 mode. For synchronous compensators the direction of rotation shall be agreed between
282 Manufacturer and Purchaser. This direction of rotation shall be marked as per 6.7.
283 If not otherwise specified, all Machines apart from Synchronous and Motor generators in the
284 scope of IEC 60034-3 or IEC 60034-33 shall have a clockwise direction of rotation.”
285 For other Machines configurations, including unidirectional machines, apart for Synchronous
286 generators and motor-generators in the scope of 60034-3 or 60034-33 shall have an arrow
287 located on the enclosure to show the direction of rotation.
288 6 Rules for terminal markings
289 6.1 General
290 6.1.1 Application
291 A terminal marking shall identify all winding and auxiliary device terminations accessible to the
292 user.
293 NOTE External line connections and winding arrangements used for common applications are shown in Annex A.
IEC 60034-8 ED4 © IEC 2025 13
294 6.1.2 Marking instructions
295 All three-phase a.c. machines with more than three terminals and all other machines (and
296 auxiliary devices) with more than two terminals shall have connecting instructions consistent
297 with this standard.
IEC 60034-8 ED4 © IEC 2025 14
299 6.1.3 Alphanumeric marking notation
300 The terminal marking comprises upper-case Latin characters and Arabic numerals. The
301 characters shall be arranged without spaces.
302 Each winding, winding phase or auxiliary circuit shall be assigned a letter symbol(s) in
303 accordance with Clause 4.
304 To prevent confusion with the numerals 1 and 0, the letters “I” and “O” shall not be used.
305 6.1.4 Duplicate winding terminals
306 Several leads of a machine can have the same marking only if each of them is capable of
307 completely fulfilling the same electrical function, so that either one of them can be used for the
308 connection. See Figure 9.
309 6.1.5 Shared terminals
310 When several leads or conductors are provided to share the current, the terminal markings shall
311 be identified by an additional numerical suffix separated by a hyphen. See Figure 10.
312 Some multi-speed motors having two or more independent windings may produce circulating
313 currents in the de-energized winding. In this case, the terminal markings for the open delta
314 connection shall be identified by an additional numerical suffix separated by a hyphen. See
315 Figure A.15.
316 6.1.6 Omission
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