SIST EN IEC 60034-2-3:2020

SLOVENSKI STANDARD
oSIST prEN IEC 60034-2-3:2019
01-marec-2019
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Rotating electrical machines - Part 2-3: Specific test methods for determining losses and
efficiency of converter-fed AC motor
Ta slovenski standard je istoveten z: prEN IEC 60034-2-3:2019
ICS:
29.160.01 Rotacijski stroji na splošno Rotating machinery in
general
oSIST prEN IEC 60034-2-3:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60034-2-3:2019

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oSIST prEN IEC 60034-2-3:2019
2/1933/CDV

COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60034-2-3 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2019-01-04 2019-03-29
SUPERSEDES DOCUMENTS:
2/1879/CD,2/1903A/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 electrical machines – Part 2-3: Specific test methods for determining losses and efficiency of
converter-fed AC motor

PROPOSED STABILITY DATE: 2021

NOTE FROM TC/SC OFFICERS:


Copyright © 2018 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
INTRODUCTION . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviated terms . 7
5 Basic requirements . 8
5.1 Instrumentation . 8
5.1.1 General . 8
5.1.2 Power analyser and transducers . 8
5.1.3 Mechanical output of the motor . 9
5.2 Converter set-up . 9
5.2.1 General . 9
5.2.2 Comparable converter set-up for rated voltages up to 1 kV . 9
5.2.3 Testing with converters with rated voltages above 1 kV . 10
5.2.4 Testing with other converters . 10
6 Test method for the determination of the efficiency of converter-fed motors . 10
6.1 Selection of determination method . 10
6.2 Method 2-3-A - Input-output method . 10
6.2.1 Test set-up . 10
6.2.2 Test procedure . 11
6.2.3 Efficiency determination . 11
6.2.4 Measurement at seven standardized operating points . 11
6.3 Method 2-3-B - Summation of losses with determination of additional high
frequency loss at converter supply at no-load operation . 11
6.3.1 Test set-up . 12
6.3.2 Test procedure . 12
6.3.3 Efficiency determination . 12
6.4 Alternate Efficiency Determination Method (AEDM) . 12
6.5 Determination of efficiency by calculation . 13
7 Interpolation of losses at any operating point . 13
7.1 Interpolation procedure . 13
7.2 Analytical determination of relative losses at any operating point . 13
7.3 Additional losses due to frequency converter voltage drop . 15
7.4 Alternate operating points to determine interpolation coefficients . 15
7.5 Optional determination of interpolation error . 16
Annex A (informative) Losses of AC motors . 17
2
A.1 Stator and rotor winding I R losses P (P + P ) . 17
LSR LS LR
A.2 Iron losses (P ) . 17
Lfe
A.3 Additional load losses (P ) . 17
LL
A.4 Friction and windage losses (P ) . 18
Lfw
A.5 Additional high frequency losses (P ) . 18
LHL
Annex B (informative) Exemplary determination of losses and efficiency at various load
points . 19
Bibliography . 21

Figure 1 – Standardized operating points . 14

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Table 1 – Preferred test methods . 10
Table 2 – Other test methods . 10
Table 3 – Normative operating points . 14
Table 4 – Non-normative alternate operating points . 15
Table A.1 – Recommended split of windage and friction losses for IC 411 self-
ventilated motors . 18

Frei verwendbar

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1 INTERNATIONAL ELECTROTECHNICAL COMMISSION
2 ____________
3
4 ROTATING ELECTRICAL MACHINES –
5
6 Part 2-3: Specific test methods
7 for determining losses and efficiency of converter-fed AC motors
8
9 INTRODUCTION
10 The objective of this standard is to define test methods for determining total losses including
11 additional high frequency motor losses and efficiency of converter-fed motors. Additional high
12 frequency losses appear in addition to the losses on nominally sinusoidal power supply as
13 determined by the methods of IEC 60034-2-1. Results determined according to this standard
14 are intended to allow comparison of losses and efficiency of different motors when fed by
15 converters.
16 Furthermore, the standard gives seven standardized operating points to characterize the
17 development of losses and efficiency across the whole torque/speed range. An interpolation
18 procedure is provided to calculate losses and efficiency at any operating point (torque,
19 speed).
20 In power-drive systems (PDS), the motor and the frequency converter are often manufactured
21 by different suppliers. Motors of the same design are produced in large quantities. They may
22 be operated from the grid or from frequency converters of many different types, supplied by
23 many different manufacturers. The individual converter properties (switching frequency, DC
24 link voltage level, etc.) will also influence the system efficiency. As it is impractical to
25 determine motor losses for every combination of motor, frequency converter, connection
26 cable, output filter and parameter settings, this standard describes a limited number of
27 approaches, depending on the voltage level and the rating of the machine under test.
28 The losses determined according to this standard are not intended to represent the losses in
29 the final application. They provide, however, an objective basis for comparing different motor
30 designs with respect to suitability for converter operation.
31 In general, when fed from a converter, motor losses are higher than during operation on a
32 nominally sinusoidal system. The additional high frequency losses depend on the harmonic
33 spectrum of the impressed converter output quantity (either current or voltage) which is
34 influenced by its circuitry and control method. For further information, see IEC/TS 60034-25.
35 It is not the purpose of this standard to define test procedures either for power drive systems
36 or for frequency converters alone.
37 Comparable converter
38 Latest experience and theoretical analysis have shown that the additional high frequency
39 motor losses generally do not generally increase much with load. The methods in this
40 standard are mainly based on supplies from converters with pulse width modulation (PWM).
41 With respect to these types of converters and the growing need for verification of compliance
42 with national energy efficiency regulations, this standard defines a so-called comparable
43 converter for testing of low voltage motors.
44 In principle, the comparable converter is a voltage source with a typical high frequency
45 harmonic content supplying the machine under test. It is not applicable to medium voltage
46 motors.

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47 Limitations for the application of the comparable converter
48 It has to be noted that the test method with the comparable converter described herein is a
49 standardized method intended to give comparable efficiency figures for standardized test
50 conditions. A motor ranking with respect to suitability for converter operation may be derived,
51 but it is not equivalent to determining of the actual motor losses for operation with a specific
52 converter which requires a test of the whole power drive system (PDS) with the specific
53 converter used in the final application.
54 Deviations are also expected for motors driven by multi-level voltage source or current source
55 converters where the additional high frequency motor losses differ much more depending on
56 speed and load than for two-level voltage source converters. Hence the determination of
57 losses and efficiency should preferably use procedures where the motor is operated together
58 with the same converter with which it is driven in service.
59 Another option is the determination of the additional high frequency motor losses by
60 calculation. If this is requested by the customer, the pulse pattern of the converter is required.
61 Such procedures are not part of this standard.
62 The provided interpolation procedure for the determination of losses and efficiency at any
63 operating point (torque, speed) is limited to the base speed range (constant torque range,
64 constant flux range).
65
Frei verwendbar

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66 ROTATING ELECTRICAL MACHINES –
67
68 Part 2-3: Specific test methods
69 for determining losses and efficiency of converter-fed AC motors
70
71
72
73 1 Scope
74 This standard specifies test methods and an interpolation procedure for determining losses
75 and efficiencies of converter-fed motors within the scope of IEC 60034-1. The motor is then
76 part of a variable frequency power drive system (PDS) as defined in IEC 61800-9-2.
77 Applying the approach of the comparable converter, the motor efficiency determined by use of
78 this standard is applicable for comparison of different motor designs only.
79 The standard also specifies procedures to determine motor losses at any load point (torque,
80 speed) within the base speed range (constant torque range, constant flux range) based on
81 determination of losses at seven standardized load points. This procedure is applicable to any
82 variable speed AC motor (induction and synchronous) rated according to IEC 60034-1 for
83 operation on a variable frequency and variable voltage power supply.
84 2 Normative references
85 The following documents, in whole or in part, are normatively referenced in this document and
86 are indispensable for its application. For dated references, only the edition cited applies. For
87 undated references, the latest edition of the referenced document (including any
88 amendments) applies.
89 IEC 60034-1, Rotating electrical machines – Part 1: Rating and performance
90 IEC 60034-2-1:2014, Rotating electrical machines – Part 2-1: Standard methods for
91 determining losses and efficiency from tests (excluding machines for traction vehicles)
92 IEC 60034-2-2, Rotating electrical machines – Part 2-2: Specific methods for determining
93 separate losses of large machines from test – Supplement to IEC 60034-2-1
94 IEC 61000-2-4, Electromagnetic compatibility (EMC) – Part 2-4: Environment – Compatibility
95 levels in industrial plants for low-frequency conducted disturbances
96 IEC TS 61800-8, Adjustable speed electrical power drive systems. – Part 8: Specification of
97 voltage on the power interface
98 IEC 61800-9-2:2017, Adjustable speed electrical power drive systems – Part 9-2: Ecodesign
99 for power drive systems, motor starters, power electronics & their driven applications - Energy
100 efficiency indicators for power drive systems and motor starters
101
102 3 Terms and definitions
103 For the purposes of this document the terms and definitions given in IEC 60034-1, IEC 60034-
104 2-1:2014 as well as the following apply.
105 3.1
106 motor losses with converter supply
107 When powered by a converter, motor losses are a combination of losses caused by
108 fundamental frequency and losses caused by the converter high frequencies.

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109 3.2
110 fundamental losses
111 Fundamental losses in the motor can be segregated into five different components: iron
112 losses (varying with motor frequency and applied fundamental voltage), friction and windage
113 losses (varying with motor speed), rotor winding losses, stator winding losses and additional
114 load losses (all three varying with motor current). Fundamental losses are the losses of a
115 motor running with application of rated voltage at fundamental frequency that does not contain
116 any further high frequencies.
117 3.3
118 additional high frequency losses
119 Additional high frequency losses are produced in the motor by the non-sinusoidal voltage and
120 current waveforms generated by the converter and are in addition to the losses of iron, friction
121 and windage, rotor winding, stator winding and additional load loss (fundamental losses).
122 3.4
123 base speed range
124 The speed range from standstill up to the highest speed where the motor can be supplied with
125 a voltage that changes in proportion to the speed so that the magnetic flux remains constant
126 (constant ratio U/f) for induction machines and according to the MTPA (maximum torque per
127 ampere) for synchronous machines. Within the base speed range, the maximum motor torque
128 is constant (constant torque range), if constant flux control is used.
129 3.5
130 switching frequency
131 The switching frequency is the number of switching events of one semiconductor within one
132 second. It determines, together with the selected pulse pattern and the converter topology,
133 the lowest frequency of non-controllable high frequencies or inter-harmonics at the IPC (in-
134 plant point of coupling) or the motor.
135 NOTE For a two level converter, the pulse frequency measured phase to phase is two times the switching
136 frequency defined in 3.5 in case of continuous modulation and about 1.33 times the switching frequency defined in
137 3.5 in case of discontinuous modulation. A switching event is once on and once off of one semiconductor.
138
139 4 Symbols and abbreviated terms
140 For the purposes of this document the symbols given in IEC 60034-2-1, IEC TS 61800-8 as
141 well as the following apply.
142 PWM Pulse width modulation,
143 f Frequency, Hz,
144 f Fundamental motor frequency, Hz,
Mot
145 f Rated motor frequency, Hz,
N
146 f Switching frequency, Hz,
sw
147 I No-load current, A,
0
148 I Rated current, A,
N
149 MTPA Maximum torque per ampere control applied to interior permanent magnet
150 synchronous motors
–1
151 n Speed, min
–1
152 n Rated speed, min ,
N
–1
153 n Reference speed, min ,
ref
154 P Power, W,

155 P Constant losses at converter supply, W,
Ccon
Frei verwendbar

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156 P Constant losses at sinusoidal supply according to IEC 60034-2-1:2014, W,
Csin
157 PDS Power drive system,
158 P Additional high frequency loss due to converter supply, W,
LHL
159 P Rated power, W,
N
160 P Reference power, W,
ref
161 P Motor input power at converter supply, W,
1C
162 P Motor input power as tested according to IEC 60034-2-1:2014, W,
1_60034-2-1
163 P Motor output power at converter supply, W,
2C
164 P Motor output power as tested according to IEC 60034-2-1:2014, W,
2_60034-2-1
165 T Machine torque, Nm,
166 T Machine torque at converter supply, Nm,
C
167 T Rated torque, Nm,
N
168 T Reference torque, Nm,
ref
169 U Rated motor voltage, V.
N
170 η Efficiency.
171 5 Basic requirements
172 5.1 Instrumentation
173 5.1.1 General
174 Unless otherwise stated in this standard, the arithmetic average of the three line currents and
175 voltages shall be used.
176 When testing electric machines under load, slow fluctuations in the output power and other
177 measured quantities may be unavoidable. Therefore for each load point many readings shall
178 be taken automatically by a suitable digital meter over a period of at least 15 s but not more
179 than 60 s and this average shall be used for the determination of efficiency.
180 Considering the high frequencies involved in converters feeding AC motors and their
181 contribution to the motor losses, the measuring equipment has to be selected according to the
182 range of relevant frequencies with sufficient accuracy.
183 For temperature measurements, a thermosensor installed in the hot spot may be optionally
184 used, as described in IEC 60034-2-1:2014.
185 5.1.2 Power analyser and transducers
186 The instrumentation for measuring power and current at the motor’s input shall basically meet
187 the requirements of IEC 60034-2-1:2014, but due to higher frequency components the
188 following additional requirements shall also apply.
189 The specified uncertainty of the power meters shall be 0,2% of the rated apparent power of
190 the motor or better for the total active power at 50 or 60 Hz. This is the total uncertainty of the
191 power meter including possible sensors.
192 NOTE 1 For example, when a three-phase motor has a rated voltage of 400 V and a rated current of 10 A then the
193 power meter's active power uncertainty should be 0,2% of √3 times 4000 VA, which is 13,9 W or better.
194 The bandwidth of power meters and sensors shall be sufficiently wide that the error in the
195 measurement of total active power for the entire frequency range (beyond 50 Hz and 60 Hz) is
196 less than or equal to 0,3% of the apparent power.
197 NOTE 2 In general, a bandwidth from 0 Hz up to 10 times of switching frequency is sufficient.
198

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199 It is preferred to feed current and voltage directly into the power analyser. If an external
200 current transducer is required, no conventional current transformers shall be used. Instead,
201 wide bandwidth shunts or zero-flux transducers shall be used.
202 Fundamental voltage shall be measured at the motor terminals using a digital power analyser
203 equipped with suitable software (FFT, Fast Fourier Transformation).
204 Internal line filters in digital power meters shall be turned off. Synchronization filters (also
205 known as zero-cross filters) that are not in the signal path may be used.
206 For power measurement, the three-wattmeter method is preferred. All cables used to transmit
207 measurement signals shall be shielded. It has to be noted, that the cable shield is not routed
208 through the current transformers.
209 5.1.3 Mechanical output of the motor
210 The instrumentation used to measure supply frequency shall have an accuracy of ±0,1% of
211 full scale. The speed measurement should be accurate within 0,1 revolution per minute for
-1
212 and 0,03% above.
speeds up to 3000 min
213 The instrumentation used to measure the torque shall have a minimum class of 0,2 when the
214 rated efficiency is expected to be below 90% and 0,1 or better for higher efficiencies. The
215 minimum torque measured shall be at least 10% of the torque meter’s nominal torque. If a
216 better class instrument is used, the allowed torque range can be extended accordingly.
217 5.2 Converter set-up
218 5.2.1 General
219 For all tests using the comparable converter, it should be parameterized according to the
220 requirements of this standard or, if a unique combination of converter and motor is to be
221 tested, the converter should be parameterized according to the specific application
222 requirements. The chosen parameter settings shall be recorded in the test report.
223 5.2.2 Comparable converter set-up for rated voltages up to 1 kV
224 The comparable converter has to be understood as a voltage source independent of load
225 current.
226 It has to be noted, that the so-called comparable converter operating mode is not intended or
227 requested for any commercial application, but it is a typical set-up. The purpose of the
228 comparable converter set-up is to establish comparable test conditions for motors designed
229 for operation with commercially available converters.
230 The reference conditions defined below shall only be used for verification of compliance with
231 national energy efficiency regulations, in particular the 90% speed and 100% torque load
232 point. For all other purposes including the interpolation procedure according to Annex A
233 preferably the original system configuration should be used.
234 The following reference conditions are defined:
235 • Two level voltage source converter.
236 • No additional components influencing output voltage or output current shall be
237 installed between the comparable converter and the motor, except those required for
238 the measuring instruments.
239 • Operation at 90% speed and rated torque with constant rated flux (approx. 90% of
240 rated voltage) for both induction machines and synchronous machines.
241 NOTE The rated flux is defined by the rated voltage given on the name plate of the motor. Therefore, a
242 measurement at the 90% speed and 100% torque point with rated flux will be fully replicable for regulation
243 authorities.
-1
244 • For motors with a rated speed up to 3600 min , the switching frequency shall not be
245 higher than 4 kHz.
Frei verwendbar

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246 • For motors with a rated speed above 3600 min , the switching frequency shall not be
247 higher than 8 kHz.
248 NOTE The conductor cross-sectional area of the motor cable should be selected such that the voltage drop is
249 not significant at rated load. An example for a typical test setup can be found in IEC 61800-9-2.
250
251 5.2.3 Testing with converters with rated voltages above 1 kV
252 For converters with voltage ratings above 1 kV a generally accepted comparable converter
253 and cable length cannot be specified. Such motors, cables and specific converters can only
254 be tested as a complete power drive system because the pulse patterns of frequency
255 converters for higher output powers vary between manufacturers and differ greatly between
256 no-load and rated load.
257 5.2.4 Testing with other converters
258 Motors that are operated with converters that produce a voltage with less harmonic content
259 than in case of supply by the comparable converter, for example multi-level converters or
260 converters with higher switching frequencies, will typically have lower losses compared with
261 measurements made with the reference converter at 4 or 8 kHz switching frequency.
262 Reference measurements on such motors shall still be performed under the reference
263 conditions as given above. Motor efficiency values measured under non-reference conditions
264 can be provided in the motor documentation.
265 6 Test method for the determination of the efficiency of converter-fed motors
266 6.1 Selection of determination method
267 For the verification of the rated losses and energy efficiency according to energy efficiency
268 classification schemes, the preferred method 6.2 shall be applied. Verification may be
269 required by end-users and regulators.
270 Table 1 – Preferred test methods
Ref Method Description Subclause Required facility
2-3-A Input-output Torque measurement 6.2 Torque meter or dynamometer
for full-load; Comparable or
specific converter supply
271
272 Alternate efficiency determining methods according to 6.3, 6.4 and 6.5 may be used for other
273 requirements.
274 Table 2 – Other test methods
Ref Method Description Subclause Required facility
2-3-B Summation of losses Additional high 6.3 Sinusoidal supply and specific
frequency loss converter supply at no-load

determination with operation
converter for final
application
  6.4
  6.5
275
276 6.2 Method 2-3-A - Input-output method
277 6.2.1 Test set-up
278 This is a test method in which the mechanical power P of a machine is determined by
2C
279 measurement of the shaft torque and speed. The electrical power P of the stator is
1C
280 measured in the same test.

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281 6.2.2 Test procedure
282 Tests shall be conducted with converter and an assembled motor with the essential
283 components in place, to obtain test conditions equal or very similar to normal operating
284 conditions.
285 Couple the motor under test to a load machine with a torque meter or a dynamometer.
286 Operate the machine under test at rated torque and speed until thermal equilibrium (rate of
287 change of 1 K or less per half hour) has been reached.
288 At the end of the heat run, record:
289 T Output torque at converter supply
C
290 n Speed
291 P Motor input power at converter supply
1C
292 Check the offset of the torque meter after stopping the machines. In case of permanent
293 magnet machines, physically uncouple the motor under test, in order to avoid residual torque
294 in unexcited condition induced by permanent magnets.
295 Correct the output torque T by the determined offset.
C
296 6.2.3 Ef
...