oSIST prEN IEC 60034-12:2023

SLOVENSKI STANDARD
oSIST prEN IEC 60034-12:2023
01-junij-2023
Električni rotacijski stroji - 12. del: Zagonska zmogljivost indukcijskih motorjev s
trifazno kletko z eno hitrostjo
Rotating electrical machines - Part 12: Starting performance of single-speed three-phase
cage induction motors
Drehende elektrische Maschinen - Teil 12: Anlaufverhalten von Drehstrommotoren mit
Käfigläufer ausgenommen polumschaltbare Motoren
Machines électriques tournantes - Partie 12: Caractéristiques de démarrage des moteurs
triphasés à induction à cage à une seule vitesse
Ta slovenski standard je istoveten z: prEN IEC 60034-12:2023
ICS:
29.160.30 Motorji Motors
oSIST prEN IEC 60034-12:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60034-12:2023

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oSIST prEN IEC 60034-12:2023
2/2132/CDV

COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60034-12 ED4
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2023-04-28 2023-07-21
SUPERSEDES DOCUMENTS:
2/2107/CD, 2/2130/CC

IEC TC 2 : ROTATING MACHINERY
SECRETARIAT: SECRETARY:
United Kingdom Mr Charles Whitlock
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

TC 9
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,
• any relevant “in some countries” clauses to be included should this proposal proceed. Recipients are reminded that the
enquiry stage is the final stage for submitting "in some countries" clauses. See AC/22/2007.

TITLE:
Rotating electrical machines – Part 12: Starting performance of single-speed three-phase cage induction motors

PROPOSED STABILITY DATE: 2026

NOTE FROM TC/SC OFFICERS:


Copyright © 2023 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 . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Symbols . 7
5 Designation . 7
5.1 General . 7
5.2 Design N . 7
5.3 Design NE . 8
5.4 Designs NY and NEY . 8
5.5 Design H . 8
5.6 Design HE . 8
5.7 Designs HY and HEY . 8
6 Design N requirements . 8
6.1 Torque characteristics . 8
6.2 Locked rotor current and apparent power . 8
6.3 Starting requirements . 9
7 Design NE starting requirements . 9
8 Designs NY and NEY starting requirements . 9
9 Design H requirements . 9
9.1 Starting torque . 9
9.2 Locked rotor current and apparent power . 9
9.3 Starting requirements . 10
10 Design HE starting requirements . 10
11 Designs HY and HEY starting requirements . 10
12 Determination of current and torque from measurement. 10
12.1 Locked-rotor current and locked-rotor torque . 10
12.2 Breakdown torque . 10
12.3 Torque-speed curve and current-speed curve . 11
12.3.1 Torque-speed and current-speed curves from direct measurement
(method a) . 11
12.3.2 Torque-speed and current-speed curves from acceleration (method b) . 11
12.3.3 Torque-speed and current-speed curves from measured input power
(method c) . 12
12.4 Correction of data for tests performed at reduced voltage and/or other than
rated frequency . 12
Annex A Current and torque characteristics with locked rotor (informative) . 17
Annex B Correction method for test done on reduced voltage (informative) . 20

Table 1 – Minimum values of torques for design N . 13
Table 2 – Maximum values of locked rotor apparent power for designs N and H . 13
Table 3 – Maximum values of locked rotor apparent power for designs NE and HE . 13
Table 4 – External moment of inertia (J) . 14
Table 5 – Minimum values of torques for design H . 15
Table 6 – Minimum values of torques for design N motors with type of protection 'Ex eb –
increased safety' . 15
Table 7 – External moment of inertia (J) for motors with type of protection 'Ex eb –
increased safety' . 16

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oSIST prEN IEC 60034-12:2023
IEC CDV 60034-12 © IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ROTATING ELECTRICAL MACHINES –

Part 12: Starting performance of single-speed
three-phase cage induction motors

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60034-12 has been prepared by IEC technical committee 2:
Rotating machinery.
This fourth edition cancels and replaces the second edition, published in 2016. It constitutes a
technical revision.

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The main technical changes with regard to the previous edition are as follows:
Clause or
Change
subclause
Table 6 Aligned with the requirements for explosion protected motors from TC31 WG27
12 New clause on methods for measuring locked-rotor current and torque
Annex A New informative annex on the general current and torque characteristics with locked rotor
Annex B New informative annex on correction of voltage and frequency

The text of this standard is based on the following documents:
CDV Report on voting
2/1789/CDV 2/1821A/RVC

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60034 series, published under the general title Rotating electrical
machines, can be found on the IEC website.
NOTE A table of cross-references of all IEC TC 2 publications can be found in the IEC TC 2 dashboard on the
IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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oSIST prEN IEC 60034-12:2023
IEC CDV 60034-12 © IEC 2023 – 5 –
1 ROTATING ELECTRICAL MACHINES –
2
3 Part 12: Starting performance of single-speed
4 three-phase cage induction motors
5
6
7
8 1 Scope
9 This part of IEC 60034 specifies the parameters for eight designs of starting performance of
10 single-speed three-phase 50 Hz or 60 Hz cage induction motors in accordance with
11 IEC 60034-1 that:
12 – have a rated voltage up to 1 000 V;
13 – are intended for direct-on-line or star-delta starting;
14 – are rated on the basis of duty type S1;
15 – are constructed to any degree of protection as defined in IEC 60034-5 and explosion
16 protection.
17 This document also applies to dual voltage motors provided that the flux saturation level is the
18 same for both voltages.
19 The values of torque, apparent power and current given in this document are limiting values
20 (that is, minimum or maximum without tolerance).
21 NOTE 1 It is not expected that all manufacturers will produce machines for all eight designs. The selection of any
22 specific design in accordance with this document will be a matter of agreement between the manufacturer and the
23 purchaser.
24 NOTE 2 Designs other than the eight specified may be necessary for particular applications.
25 NOTE 3 It should be noted that values given in manufacturers' catalogues may include tolerances in accordance
26 with IEC 60034-1.
27 NOTE 4 The values tabled for locked rotor apparent power are based on r.m.s. symmetrical steady state locked
28 rotor currents. The start of the motor leads to transient asymmetrical currents in the whole supply, so called inrush
29 currents, which may range from 1,8 to 2,8 times the steady state locked rotor value. The current peak and decay
30 time are a function of the motor design and switching angle. Similar effects can occur during the switchover from
31 star to delta operation. A more detailed description is provided in Annex A.
32 NOTE 5 The application of the test methods described in clause 12 of this standard may be applied to cage
33 induction motors outside the scope of this standard, as well. However, special care must be taken in such cases to
34 prevent overheating of the stator or the rotor winding depending on the concrete method and parameters chosen.
35 2 Normative references
36 The following documents are referred to in the text in such a way that some or all of their
37 content constitutes requirements of this document. For dated references, only the edition
38 cited applies. For undated references, the latest edition of the referenced document (including
39 any amendments) applies.
40 IEC 60034-30-1, Rotating electrical machines – Part 30-1: Efficiency classes of line-operated
41 AC motors (IE-code)
42 IEC 60079-7:2015, Explosive atmospheres – Part 7: Equipment protection by increased safety
43 "e"

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44 3 Terms and definitions
45 For the purposes of this document, the following terms and definitions apply.
46 ISO and IEC maintain terminological databases for use in standardization at the following
47 addresses:
48 • IEC Electropedia: available at http://www.electropedia.org/
49 • ISO Online browsing platform: available at http://www.iso.org/obp
50 3.1
51 rated torque
52 T
N
53 torque the motor develops at its shaft end at rated output and speed
54 [SOURCE: IEC 60050-411:1996, 411-48-05]
55 3.2
56 locked-rotor torque
57 T
l
58 smallest measured torque the motor develops at its shaft end with the rotor locked, over all its
59 angular positions, at rated voltage and frequency
60 [SOURCE: IEC 60050-411:1996, 411-48-06]
61 3.3
62 pull-up torque
63 T
u
64 smallest steady-state asynchronous torque which the motor develops between zero speed
65 and the speed which corresponds to the breakdown torque, when the motor is supplied at the
66 rated voltage and frequency
67 Note 1 to entry: This definition does not apply to those motors whose torque continually decreases with increase
68 in speed.
69 Note 2 to entry: In addition to the steady-state asynchronous torques, harmonic synchronous torques, which are a
70 function of rotor load angle, will be present at specific speeds. At such speeds, the accelerating torque may be
71 negative for some rotor load angles. Experience and calculation show this to be an unstable operating condition
72 and therefore harmonic synchronous torques do not prevent motor acceleration and are excluded from this
73 definition.
74 3.4
75 breakdown torque
76 T
b
77 maximum steady-state asynchronous torque which the motor develops without an abrupt drop
78 in speed, when the motor is supplied at the rated voltage and frequency
79 Note 1 to entry: This definition does not apply to those motors whose torque continually decreases with increase
80 in speed.
81 3.5
82 rated output
83 P
N
84 value of the output included in the rating
85 3.6
86 rated voltage
87 U
N
88 value of the voltage included in the rating

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89 3.7
90 locked rotor apparent power
91 S
l
92 apparent power input with the motor held at rest at rated voltage and frequency after the
93 inrush currents have decayed to a symmetrical system of current
94 3.8
95 locked rotor current
96 I
l
97 current with the motor held at rest at rated voltage and frequency after the inrush currents
98 have decayed to a symmetrical system of current

99 4 Symbols
Symbol Quantity
I Locked rotor current

l
J External moment of inertia
J Moment of inertia of motor under test
M
n Rotational speed
p Number of pole pairs
P Power at the motor terminals during test method c)

1
P Power at the generator terminals during test method a)

1,g
P Motor iron losses during test method c)

Fe
P
Motor I²R losses during test method c)
L
P Total losses of the generator during test method a)

T,g
P Rated output

N
S
Locked rotor apparent power
l
T Rated torque
N
T Locked rotor torque

l
T Pull-up torque
u
T Breakdown torque
b
T Motor friction and windage torque during test method c)
fw
U Rated voltage
N
100
101 5 Designation
102 5.1 General
103 Motors designed according to this document are classified according to 5.2 to 5.7. The letters
104 used to specify the different designs stand for:
105 N: normal starting torque
106 H: high starting torque
107 Y: star-delta starting
108 E: motors utilizing extended / higher locked rotor apparent power and current to achieve
109 efficiency classes of IE3 or higher according to IEC 60034-30-1
110 5.2 Design N
111 Normal starting torque three-phase cage induction motors, intended for direct-on-line starting,
112 having 2, 4, 6 or 8 poles, rated from 0,12 kW to 1 600 kW.

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113 5.3 Design NE
114 Normal starting torque three-phase cage induction motors having higher locked rotor apparent
115 power than design N, intended for direct-on-line starting, having 2, 4, 6 or 8 poles, rated from
116 0,12 kW to 1 600 kW. ‘
117
118 5.4 Designs NY and NEY
119 Motors similar to designs N or NE, respectively, but intended for star-delta starting. For these
120 motors in star-connection, minimum values for T and T are 25 % of the values of design N or
l u
121 NE, respectively, see Table 1.
122 5.5 Design H
123 High starting torque three-phase cage induction motors with 4, 6 or 8 poles, intended for
124 direct-online starting, rated from 0,12 kW to 160 kW at a frequency of 60 Hz.
125 5.6 Design HE
126 High starting torque three-phase cage induction motors having higher locked rotor apparent
127 power than design H, with 4, 6 or 8 poles, intended for direct-online starting, rated from
128 0,12 kW to 160 kW at a frequency of 60 Hz.
129 5.7 Designs HY and HEY
130 Motors similar to designs H or HE, respectively, but intended for star-delta starting. For these
131 motors in star-connection, minimum values for T and T are 25 % of the values of design H or
l u
132 HE, respectively, see Table 5.
133 6 Design N requirements
134 6.1 Torque characteristics
135 The starting torque is represented by three characteristic features. These features shall be in
136 accordance with the appropriate values given in Table 1 or Table 6. The values in Table 1 and
137 Table 6 are minimum values at rated voltage. Higher values are allowed.
138 The motor torque at any speed between zero and that at which breakdown torque occurs shall
139 be not less than 1,3 times the torque obtained from a curve varying as the square of the
140 speed and being equal to rated torque at rated speed. However, for 2-pole motors with type of
141 protection 'Ex eb – increased safety' having a rated output greater than 100 kW, the motor
142 torque at any speed between zero and that at which breakdown torque occurs shall not be
143 less than 1,3 times the torque obtained from a curve varying as the square of the speed and
144 being equal to 70 % rated torque at rated speed. For motors with type of protection 'Ex eb',
145 the three characteristic torques shall be in accordance with the appropriate values given in
146 Table 6.
147 NOTE The factor 1,3 has been chosen with regard to an undervoltage of 10 % in relation to the rated voltage at
148 the motor terminals during the acceleration period.
149 6.2 Locked rotor current and apparent power
150 The locked rotor apparent power shall be not greater than the appropriate value given in
151 Table 2. The values given in Table 2 are independent of the number of poles and are
152 maximum values at rated voltage. For motors with type of protection 'e', locked rotor apparent
153 power shall be in accordance with the appropriate values specified in IEC 60079-7.

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154 The locked rotor current is calculated from the locked rotor apparent power according to:
S P
l N
155 I = ×                                  (1)
l
P
3U
N
N
156 NOTE The advantage of specifying S /P instead of I /I is that the locked rotor current can be calculated from
l N l N
157 rated power and rated voltage only, not requiring to know the rated current which depends on quantities such as
158 power factor and efficiency that are usually not known in early stages of a project.
159 6.3 Starting requirements
160 Motors shall be capable of withstanding two starts in succession (coasting to rest between
161 starts) from cold conditions and one start from hot after running at rated conditions. The
162 retarding torque due to the driven load will be in each case proportional to the square of the
163 speed and equal to the rated torque at rated speed with the external moment of inertia given
164 in Table 4 or Table 7.
165 In each case, a further start is permissible only if the motor temperature before starting does
166 not exceed the steady temperature at rated load. However, for 2-pole motors with type of
167 protection 'Ex eb – increased safety' having a rated output greater than 100 kW, the retarding
168 torque due to the driven load is proportional to the square of the speed and equal to 70 %
169 rated torque at rated speed, with the external moment of inertia given in Table 7. After this
170 starting, load with rated torque is possible.
171 NOTE It should be recognized that the number of starts should be minimized since these affect the life of the
172 motor.
173 7 Design NE starting requirements
174 The starting requirements are as for design N, except that the limits for locked rotor apparent
175 power in Table 3 apply, as increasing efficiency values require physically increasing values
176 for locked rotor apparent power.
177 8 Designs NY and NEY starting requirements
178 The starting requirements are as for designs N or NE, respectively. In addition, however, a
179 reduced retarding torque is necessary as the starting torque in ‘star connection’ may be
180 insufficient to accelerate some loads to an acceptable speed.
181 NOTE It should be recognized that the number of starts should be minimized since these affect the life of the
182 motor.
183 9 Design H requirements
184 9.1 Starting torque
185 The starting torque is represented by three characteristic features. These features shall be in
186 accordance with the appropriate values given in Table 5. These values are minimum values at
187 rated voltage. Higher values are allowed.
188 9.2 Locked rotor current and apparent power
189 The locked rotor apparent power shall be not greater than the appropriate value given in
190 Table 2. The values in Table 2 are independent of the number of poles and are maximum
191 values at rated voltage.

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192 The locked rotor current is calculated from the locked rotor apparent power according to the
193 formula given in 6.2.
194 9.3 Starting requirements
195 Motors shall be capable of withstanding two starts in succession (coasting to rest between
196 starts) from cold conditions, and one start from hot after running at rated conditions. The
197 retarding torque due to the driven load is assumed to be constant and equal to rated torque,
198 independent of speed, with an external moment of inertia of 50 % of the values given in
199 Table 4.
200 In each case, a further start is permissible only if the motor temperature before starting does
201 not exceed the steady temperature at rated load.
202 NOTE It should be recognized that the number of starts should be minimized since these affect the life of the
203 motor.
204 10 Design HE starting requirements
205 The starting requirements are as for design H, except that the limits for locked rotor apparent
206 power in Table 3 apply, as increasing efficiency values require physically increasing values
207 for locked rotor apparent power.
208 11 Designs HY and HEY starting requirements
209 The starting requirements are as for design H or HE, respectively. In addition, however, a
210 reduced retarding torque is necessary as the starting torque in ‘star connection’ may be
211 insufficient to accelerate some loads to an acceptable speed.
212 NOTE It should be recognized that the number of starts should be minimized since these affect the life of the
213 motor.
214 12 Determination of current and torque from measurement
215 12.1 Locked-rotor current and locked-rotor torque
216 When possible, the locked-rotor current shall be measured at rated voltage and frequency as
217 the current is not directly proportional to the voltage because of changes in reactance caused
218 by saturation of the leakage paths. In case this isn’t possible, see subclause 12.4.
219
220 The locked-rotor torque may be measured with e.g. a scale or force transducer with a brake or
221 beam, or it may be measured directly using an in-line torque transducer, or it may be
222 determined from the electrical input power using equation (5) from subclause 12.3.3.
223 Depending on the chosen number of rotor slots, the locked-rotor torque of cage induction
224 motors is subject to variations depending on the angular position of the rotor with respect to
225 the stator. In case a preferable number of rotor slots is chosen according to the
226 manufacturer’s experience, it is usual practice to lock the rotor of a cage induction motor in
227 any convenient position or to measure current and torque values with the rotor being stalled
228 at very low speed, i. e. with a speed below 2% of the rated speed.
229
230 12.2 Breakdown torque
231 The breakdown torque can be measured by loading the motor, starting at no-load condition,
...