Rotating electrical machines - Part 28: Test methods for determining quantities of equivalent circuit diagrams for three-phase low-voltage cage induction motors

IEC 60034-28:2012 applies to three-phase low-voltage cage induction motors of frame numbers 56 to 400 as specified in IEC 60072-1. This standard establishes procedures to obtain values for elements of single phase equivalent circuit diagrams from tests and defines standard elements of these diagrams. This edition includes the following significant technical changes with respect to the previous edition: - the formulae are now all given for equivalent star-connection equivalent circuit diagrams; - procedures for the determination of equivalent circuit parameters from a load curve test as an alternative to the reverse rotation and locked rotor tests have been added.

Drehende elektrische Maschinen - Teil 28: Prüfverfahren zur Bestimmung der Ersatzschaltbildgrößen dreiphasiger Niederspannungs-Käfigläufer-Asynchronmotoren

Machines électriques tournantes - Partie 28: Méthodes d'essai pour la détermination des grandeurs des schémas d'équivalence des circuits pour moteurs à induction à cage basse tension triphasés

La CEI 60034-28:2012 s'applique aux moteurs à induction à cage basse tension triphasés de désignations de carcasses entre 56 et 400, spécifiés dans la CEI 60072-1. La présente norme définit des éléments normalisés de schémas de circuits équivalents monophasés et établit à partir d'essais des procédures pour obtenir des valeurs pour ces éléments. Cette édition inclut les modifications techniques significatives suivantes par rapport à l'édition précédente: - toutes les formules sont maintenant données pour des circuits de connexion en étoile équivalente; - les procédures pour la détermination des paramètres du circuit équivalent à partir d'un test de courbe de charge, comme alternative aux tests en rotation en sens inverse et rotor bloqué rotors, ont été ajoutées.

Električni rotacijski stroji - 28. del: Preskusne metode za ugotavljanje veličin nadomestnih shem trifaznih nizkonapetostnih motorjev z indukcijsko kletko (IEC 60034-28:2012)

Ta del standarda IEC 60034 se uporablja za trifazne nizkonapetostne motorje z indukcijsko kletko s številkami okvirjev 56 do 400, kot določa standard IEC 60072-1. Ta standard določa postopke za pridobivanje vrednosti za elemente enofaznih ekvivalentnih tokokrogov iz preskusov ter opredeljuje standardne elemente teh tokokrogov.

General Information

Status
Published
Publication Date
13-Jun-2013
Technical Committee
Drafting Committee
Current Stage
6060 - Document made available
Due Date
17-Apr-2013
Completion Date
14-Jun-2013

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SLOVENSKI STANDARD
SIST EN 60034-28:2013
01-september-2013
1DGRPHãþD
SIST EN 60034-28:2007
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Rotating electrical machines - Part 28: Test methods for determining quantities of

equivalent circuit diagrams for three-phase low-voltage cage induction motors (IEC

60034-28:2012)

Drehende elektrische Maschinen - Teil 28: Prüfverfahren zur Bestimmung der Größen in

Ersatzschaltbildern dreiphasiger Niederspannungs-Kurzschlussläufer-Induktionsmotoren

(IEC 60034-28:2012)

Machines électriques tournantes - Partie 28: Méthodes d'essai pour la détermination des

grandeurs des schémas d'équivalence des circuits pour moteurs à induction à cage
basse tension triphasés (CEI 60034-28:2012)
Ta slovenski standard je istoveten z: EN 60034-28:2013
ICS:
29.160.30 Motorji Motors
SIST EN 60034-28:2013 en

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

---------------------- Page: 1 ----------------------
SIST EN 60034-28:2013
---------------------- Page: 2 ----------------------
SIST EN 60034-28:2013
EUROPEAN STANDARD
EN 60034-28
NORME EUROPÉENNE
June 2013
EUROPÄISCHE NORM
ICS 29.160 Supersedes EN 60034-28:2007
English version
Rotating electrical machines -
Part 28: Test methods for determining quantities of equivalent circuit
diagrams for three-phase low-voltage cage induction motors
(IEC 60034-28:2012)
Machines électriques tournantes - Drehende elektrische Maschinen -
Partie 28: Méthodes d'essai pour la Teil 28: Prüfverfahren zur Bestimmung der
détermination des grandeurs des Ersatzschaltbildgrößen dreiphasiger
schémas d'équivalence des circuits pour Niederspannungs-Käfigläufer-
moteurs à induction à cage basse tension Asynchronmotoren
triphasés (IEC 60034-28:2012)
(CEI 60034-28:2012)

This European Standard was approved by CENELEC on 2013-01-17. 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, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60034-28:2013 E
---------------------- Page: 3 ----------------------
SIST EN 60034-28:2013
EN 60034-28:2013 - 2 -
Foreword

The text of document 2/1685/FDIS, future edition 2 of IEC 60034-28, prepared by IEC/TC 2 "Rotating

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

EN 60034-28:2013.
The following dates are fixed:
(dop) 2013-12-14
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-01-17
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60034-28:2007.

EN 60034-28:2013 includes the following significant technical changes with respect to

EN 60034-28:2007:

a) the formulae are now all given for equivalent star-connection equivalent circuit diagrams. They are

applied even in the case of delta connected windings. All formulae for delta connected equivalent

circuit diagrams have been moved to notes;

b) procedures for the determination of equivalent circuit parameters from a load curve test as an

alternative to the reverse rotation and locked rotor tests have been added.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 60034-28:2012 was approved by CENELEC as a European

Standard without any modification.
---------------------- Page: 4 ----------------------
SIST EN 60034-28:2013
- 3 - EN 60034-28:2013
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
Publication Year Title EN/HD Year
IEC 60034-1 (mod) 2010 Rotating electrical machines - EN 60034-1 2010
Part 1: Rating and performance + corr. October 2010
IEC 60034-2-1 - Rotating electrical machines - EN 60034-2-1 -
Part 2-1: Standard methods for determining
losses and efficiency from tests (excluding
machines for traction vehicles)
IEC 60034-2-2 - Rotating electrical machines - EN 60034-2-2 -
Part 2-2: Specific methods for determining
separate losses of large machines from tests
- Supplement to IEC 60034-2-1
IEC/TS 60034-2-3 - Rotating electrical machines - - -
Part 2-3: Specific test methods for
determining losses and efficiency of
converter-fed AC motors
IEC/TS 60034-25 - Rotating electrical machines - CLC/TS 60034-25 -
Part 25: Guidance for the design and
performance of a.c. motors specifically
designed for converter supply
IEC 60044 Series Instrument transformers EN 60044 Series
IEC 60051-1 - Direct acting indicating analogue electrical EN 60051-1 -
measuring instruments and their accessories
- Part 1: Definitions and general
requirements common to all parts
IEC 60072-1 - Dimensions and output series for rotating - -
electrical machines -
Part 1: Frame numbers 56 to 400 and flange
numbers 55 to 1 080
To be published.
---------------------- Page: 5 ----------------------
SIST EN 60034-28:2013
---------------------- Page: 6 ----------------------
SIST EN 60034-28:2013
IEC 60034-28
Edition 2.0 2012-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Rotating electrical machines –
Part 28: Test methods for determining quantities of equivalent circuit diagrams
for three-phase low-voltage cage induction motors
Machines électriques tournantes –
Partie 28: Méthodes d’essai pour la détermination des grandeurs des schémas
d’équivalence des circuits pour moteurs à induction à cage basse tension
triphasés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 29.160 ISBN 978-2-83220-553-2

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 60034-28:2013
– 2 – 60034-28 © IEC:2012
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope ............................................................................................................................... 7

2 Normative references ....................................................................................................... 7

3 Terms, definitions, symbols and conventions .................................................................... 7

3.1 Terms and definitions .............................................................................................. 7

3.2 Symbols .................................................................................................................. 8

3.3 Subscripts ............................................................................................................... 9

3.4 Winding connection ................................................................................................. 9

4 Test requirements .......................................................................................................... 10

4.1 General ................................................................................................................. 10

4.2 Frequency and voltage .......................................................................................... 10

4.3 Instrumentation ..................................................................................................... 10

4.3.1 Measuring instruments for electrical quantities, speed and frequency ........ 10

4.3.2 Instrument transformers ............................................................................. 10

4.3.3 Temperature measurement ........................................................................ 10

5 Approximations and uncertainties ................................................................................... 10

6 Test procedures ............................................................................................................. 11

6.1 General ................................................................................................................. 11

6.2 Stator d.c. line-to-line resistance measurement ..................................................... 11

6.3 Load-test at rated load .......................................................................................... 11

6.4 Load curve test...................................................................................................... 12

6.5 No-load test ........................................................................................................... 12

6.6 Reverse rotation and locked rotor tests ................................................................. 13

6.6.1 General ..................................................................................................... 13

6.6.2 Reverse rotation test ................................................................................. 13

6.6.3 Locked rotor test........................................................................................ 13

7 Determination of motor quantities ................................................................................... 13

7.1 General ................................................................................................................. 13

7.2 Resistance of stator winding R ............................................................................. 15

7.3 Total stator inductance L = L + L .................................................................. 15

ts m σs

7.3.1 General ..................................................................................................... 15

7.3.2 Determination procedure ........................................................................... 15

7.4 Equivalent resistance of iron losses R .............................................................. 16

feΓ

7.4.1 Constant losses ......................................................................................... 16

7.4.2 Friction and windage losses....................................................................... 17

7.4.3 Iron losses ................................................................................................. 17

7.5 Total leakage inductance L ................................................................................. 18

7.5.1 General ..................................................................................................... 18

7.5.2 Distribution of leakage inductances between stator and rotor..................... 18

7.5.3 Determination of total leakage inductance from a reverse rotation or

locked rotor test (6.6) ................................................................................ 18

7.5.4 Determination of total leakage inductance from a load curve test (6.4) ...... 20

7.6 Magnetizing inductance L and voltage U .......................................................... 21

m m

7.6.1 From a reverse rotation or locked rotor test (6.6) ....................................... 21

7.6.2 From a load curve test (6.4) ....................................................................... 21

---------------------- Page: 8 ----------------------
SIST EN 60034-28:2013
60034-28 © IEC:2012 – 3 –

7.7 Stator and rotor leakage inductances L and L ’ ................................................. 22

σs σr

7.7.1 From a reverse rotation or locked rotor test (6.6) ....................................... 22

7.7.2 From a load curve test (6.4) ....................................................................... 22

7.8 Inductances for calculations at constant flux (rated load) ....................................... 22

7.9 Resistance of rotor cage R ’ referred to the stator winding and frequency .............. 23

7.10 Equivalent resistance of iron losses R ................................................................ 25

Annex A (informative) Sample calculation ............................................................................ 26

Figure 1 – Type-T equivalent circuit diagram ........................................................................ 14

Figure 2 – Type-T equivalent circuit diagram (iron losses disregarded) ................................. 14

Figure 3 – Type-L equivalent circuit diagram (iron losses disregarded) ................................. 14

Figure 4 – Type-Γ equivalent circuit diagram......................................................................... 15

Figure 5 – Typical characteristics of inductance L over current I ........................................... 16

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SIST EN 60034-28:2013
– 4 – 60034-28 © IEC:2012
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –
Part 28: Test methods for determining quantities of equivalent circuit
diagrams for three-phase low-voltage 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

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

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

misinterpretation by any end user.

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

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

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

the latter.

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

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

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

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 60034-28 has been prepared by IEC technical committee 2:

Rotating machinery.

This second edition cancels and replaces the first edition published in 2007. This edition

constitutes a technical revision.

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

edition.

a) The formulae are now all given for equivalent star-connection equivalent circuit diagrams.

They are applied even in the case of delta connected windings. All formulae for delta-

connected equivalent circuit diagrams have been moved to notes.

b) Procedures for the determination of equivalent circuit parameters from a load curve test as

an alternative to the reverse rotation and locked rotor tests have been added.
---------------------- Page: 10 ----------------------
SIST EN 60034-28:2013
60034-28 © IEC:2012 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
2/1685/FDIS 2/1688/RVD

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.

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 web site 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 11 ----------------------
SIST EN 60034-28:2013
– 6 – 60034-28 © IEC:2012
INTRODUCTION

Equivalent circuits are widely used in the control of adjustable speed drives with induction

motors supplied by frequency inverters. The motor parameters are required for the realisation

of flux oriented control or other model-based control algorithms. Their knowledge is required

by suppliers and system engineers, especially when motors and frequency inverters from

different suppliers are combined.

This standard provides a standardized test procedure to determine the electric motor

parameters. At the same time the draft offers an improved understanding of the equivalent

circuit method. The procedures can be carried out in laboratories equipped for standard

electric machinery tests.

NOTE This standard’s main purpose is for assistance in modelling frequency controlled motors. Due to the

simplifications the results cannot be used to determine motor performance or efficiency accurately.

A related technical specification is IEC/TS 60034-25 where required motor parameters are

listed, but their definition and methods of determination are not included.
---------------------- Page: 12 ----------------------
SIST EN 60034-28:2013
60034-28 © IEC:2012 – 7 –
ROTATING ELECTRICAL MACHINES –
Part 28: Test methods for determining quantities of equivalent circuit
diagrams for three-phase low-voltage cage induction motors
1 Scope

This part of the IEC 60034 series applies to three-phase low-voltage cage induction motors of

frame numbers 56 to 400 as specified in IEC 60072-1.

This standard establishes procedures to obtain values for elements of single phase equivalent

circuit diagrams from tests and defines standard elements of these diagrams.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60034-1:2010, Rotating electrical machines – Part 1: Rating and performance

IEC 60034-2-1, Rotating electrical machines – Part 2-1: Standard methods for determining

losses and efficiency from tests (excluding machines for traction vehicles)

IEC 60034-2-2, Rotating electrical machines – Part 2-2: Specific methods for determining

separate losses of large machines from tests – Supplement to IEC 60034-2-1

IEC 60034-2-3 , Rotating electrical machines – Part 2-3: Specific test methods for

determining losses and efficiency of converter-fed AC motors

IEC/TS 60034-25 , Rotating electrical machines – Part 25: A.C. Motors when used in power

drive systems - Application guide
IEC 60044 (all parts), Instrument transformers

IEC 60051-1, Direct acting indicating analogue electrical measuring instruments and their

accessories – Part 1: Definitions and general requirements common to all parts

IEC 60072-1, Dimensions and output series for rotating electrical machines – Part 1: Frame

numbers 56 to 400 and flange numbers 55 to 1080
3 Terms, definitions, symbols and conventions
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60034-1:2010

apply.
———————
To be published.
A revision of this publication is currently under preparation.
---------------------- Page: 13 ----------------------
SIST EN 60034-28:2013
– 8 – 60034-28 © IEC:2012
3.2 Symbols
The following symbols apply:
cos ϕ is the power factor
cos ϕ is the rated power factor
f is the stator supply frequency, Hz
f is the frequency of the rotor current (slip frequency), Hz
f is the rated frequency, Hz
h is the height of the rotor-conductor bar, m

H is the motor frame size according to IEC 60072-1 (distance from the centre-line of

the shaft to the bottom of the feet (basic dimension)), mm
I is the stator line current, A
I is the stator phase current, A
I ’ is the rotor phase current, A
I is the magnetizing current, A
is the rated stator current, A
k is the skin effect factor for inductances

k is the reciprocal of the temperature coefficient of resistance at 0 °C of the rotor

conductor material, see Note 1

k is the reciprocal of the temperature coefficient of resistance at 0 °C of the stator

conductor material, see Note 1
k is the ratio of the stator to the rotor leakage inductances
L is the magnetizing inductance, H
L is the stator leakage inductance, H
L ’ is the rotor leakage inductance, H
L is the total leakage inductance (= L + L ’), H
tσ σs σr
L is the total leakage inductance disregarding the skin effect, H
L is the total stator inductance (= L + L ), H
ts m σs
L ’ is the total rotor inductance (= L + L ’), H
tr m σr
n is the operating speed, min
n is the rated speed, min
n is the rated synchronous speed, min
syn
p is the number of pole pairs
P is the electrical input power, W
P is the mechanical output power, W
P is the constant losses, W
P is the friction and windage losses, W
P is the iron losses, W
R is the line-to-line resistance, Ω
R is the equivalent circuit resistance of iron losses, Ω
R , is the stator line-to-line resistance at initial winding temperature, Ω
ll m
R is the stator phase-resistance corrected to a temperature of 25 °C, Ω
s,25°
R ’ is the rotor cage resistance, Ω
R ’ is the rotor resistance corrected to an ambient temperature of 25 °C, Ω
r,25°
---------------------- Page: 14 ----------------------
SIST EN 60034-28:2013
60034-28 © IEC:2012 – 9 –
R , ’ is the rotor resistance at initial winding temperature, Ω
r m
s is the slip, in per unit value of synchronous speed
s is the rated slip
U is the stator terminal voltage, V
is the stator phase voltage, V
U is the voltage drop over the magnetizing inductance, V
U is the rated terminal voltage, V
X is the magnetizing reactance (= 2πf ⋅L ), Ω
m N m
X is the stator leakage reactance (= 2πf ⋅L ), Ω
σs N σs
X ’ is the rotor leakage reactance (= 2πf ⋅L ’), Ω
σr N σr
X is the total leakage reactance (= 2πf ⋅L ), Ω
tσ N tσ
X is the total leakage reactance disregarding the skin effect (= 2πf ⋅L ), Ω
σa N σa
X is the total stator reactance (= 2πf ⋅L ), Ω
ts N ts
X ’ is the total rotor reactance (= 2πf ⋅L ’), Ω
tr N tr
Z is the line impedance, Ω
γ is the conductivity of rotor conductor, S/m, see Note 2
θ is the temperature of the cold winding at initial resistance measurement, °C
θ is the temperature of the winding at the end of the thermal load test, °C
θ is the temperature of the winding at the end of the thermal no-load test, °C

NOTE 1 For copper, use k = 235, for aluminium, use k = 225, unless otherwise specified.

6 6

NOTE 2 For copper rotor-bars, use γ = 56 × 10 S/m, for aluminium rotor-bars, use γ = 33 × 10 S/m unless

r r
otherwise specified.

NOTE 3 For calculations in this standard, voltages and currents are r.m.s. magnitude values (different from

vectors in complex calculations).
NOTE 4 All rotor values are referred to the stator winding and frequency.
3.3 Subscripts
L, NL, 0 test conditions
m, ma, mb magnetizing quantities
N rated value
r, tr rotor quantities
s, ts stator quantities
σ, tσ leakage quantities
3.4 Winding connection

The mathematical model of the machine shall be regarded as Y-connected, regardless of the

actual connection of the motor (delta or star). The quantities in the equivalent circuit diagram

shall be presented as per phase values in equivalent Y-connection.

NOTE For reference purposes the formulae required to calculate a delta-connected equivalent circuit diagram are

also given as notes. In case of delta connected motors these formulae can be used to create an equivalent circuit

diagram which represents the internal winding currents better than a circuit diagram in equivalent Y-connection.

---------------------- Page: 15 ----------------------
SIST EN 60034-28:2013
– 10 – 60034-28 © IEC:2012
4 Test requirements
4.1 General

The tests shall be carried out with regard to the requirements for the tests given in

IEC 60034-2-1, IEC 60034-2-2, IEC 60034-2-3 and IEC/TS 60034-25, as applicable.
4.2 Frequency and voltage

The frequency shall be within ± 0,3 % of specified test frequency during measurements. The

form and symmetry of the supply voltage shall conform to the requirements of 8.3.1 of

IEC 60034-1:2010.
4.3 Instrumentation
4.3.1 Measuring instruments for electrical quantities, speed and frequency

The measuring instruments shall have an accuracy class of 0,5 or better in accordance with

IEC 60051-1. However, accuracy class for the measurement of resistance shall be 0,1.

Since instrument accuracy is generally expressed as a percentage of full scale, the range of

the instrument chosen shall be as low as practical.
4.3.2 Instrument transformers

Instrument transformers shall have an accuracy class of 0,2 according to IEC 60044.

...

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