EN 60034-4:2008

SLOVENSKI STANDARD
01-december-2008
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SIST EN 60034-4:1999
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Rotating electrical machines - Part 4: Methods for determining synchronous machine
quantities from tests (IEC 60034-4:2008)
Drehende elektrische Maschinen - Teil 4: Verfahren zur Ermittlung der Kenngrößen von
Synchronmaschinen durch Messungen (IEC 60034-4:2008)
Machines électriques tournantes - Partie 4: Méthodes pour la détermination, à partir
d'essais, des grandeurs des machines synchrones (CEI 60034-4:2008)
Ta slovenski standard je istoveten z: EN 60034-4:2008
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.

EUROPEAN STANDARD
EN 60034-4
NORME EUROPÉENNE
September 2008
EUROPÄISCHE NORM
ICS 29.160 Supersedes EN 60034-4:1995

English version
Rotating electrical machines -
Part 4: Methods for determining synchronous machine quantities
from tests
(IEC 60034-4:2008)
Machines électriques tournantes -  Drehende elektrische Maschinen -
Partie 4: Méthodes pour la détermination, Teil 4: Verfahren zur Ermittlung
à partir d'essais, des grandeurs der Kenngrößen von Synchronmaschinen
des machines synchrones durch Messungen
(CEI 60034-4:2008) (IEC 60034-4:2008)

This European Standard was approved by CENELEC on 2008-07-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60034-4:2008 E
Foreword
The text of document 2/1488/FDIS, future edition 3 of IEC 60034-4, prepared by IEC TC 2, Rotating
machinery, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 60034-4 on 2008-07-01.
This European Standard supersedes EN 60034-4:1995.
The main changes with respect to EN 60034-4:1995 are listed below:
– tests described in supplement A of EN 60034-4:1995 were partly removed for lack of relevance in
current practice;
– provisions were made for tests on machines with brushless excitation;
– a table of test methods indicates preferred tests, and a test cross-reference is provided;
– the conventional two-axes salient-pole machine model description was added in an annex.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2009-04-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2011-07-01
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60034-4:2008 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 60034-4:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. 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 2004 Rotating electrical machines - EN 60034-1 2004
Part 1: Rating and performance

1) 2)
IEC 60034-2-1 - Rotating electrical machines - EN 60034-2-1 2007
Part 2-1: Standard methods for determining
losses and efficiency from tests (excluding
machines for traction vehicles)

1)
IEC 60034-2A - Rotating electrical machines - - -
Part 2: Methods for determining losses and
efficiency of rotating electrical machinery from
tests (excluding machines for traction
vehicles) – First supplement: Measurement of
losses by the calorimetric method

IEC 60051 Series Direct acting indicating analogue electrical EN 60051 Series
measuring instruments and their accessories

1)
Undated reference.
2)
Valid edition at date of issue.

IEC 60034-4
Edition 3.0 2008-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Rotating electrical machines –
Part 4: Methods for determining synchronous machine quantities from tests

Machines électriques tournantes –
Partie 4: Méthodes pour la détermination, à partir d’essais, des grandeurs des
machines synchrones
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XC
CODE PRIX
ICS 29.160 ISBN 2-8318-9706-8
– 2 – 60034-4 © IEC:2008
CONTENTS
FOREWORD.7
1 Scope.9
2 Normative references .9
3 Terms and definitions .9
4 Symbols and units .14
5 Overview of tests.15
6 Test procedures .18
6.1 General .18
6.1.1 Instrumentation requirements .18
6.1.2 Excitation system requirements .18
6.1.3 Test conditions .18
6.1.4 Per unit base quantities .19
6.1.5 Conventions and assumptions .19
6.1.6 Consideration of magnetic saturation.20
6.2 Direct measurements of excitation current at rated load .21
6.3 Direct-current winding resistance measurements.21
6.4 No-load saturation test .22
6.4.1 Test procedure .22
6.4.2 No-load saturation characteristic determination .23
6.5 Sustained three-phase short-circuit test .23
6.5.1 Test procedure .23
6.5.2 Three-phase sustained short-circuit characteristic .24
6.6 Motor no-load test .24
6.7 Phase shifting test.24
6.8 Over-excitation test at zero power-factor .25
6.9 Negative excitation test .25
6.10 On-load test measuring the load angle .25
6.11 Low slip test .25
6.12 Sudden three-phase short-circuit test .26
6.13 Voltage recovery test.27
6.14 Suddenly applied short-circuit test following disconnection from line .27
6.15 Direct current decay test in the armature winding at standstill test.27
6.16 Suddenly applied excitation test with armature winding open-circuited .28
6.17 Applied voltage test with the rotor in direct and quadrature axis positions .29
6.18 Applied voltage test with the rotor in arbitrary position.29
6.19 Single phase voltage test applied to the three phases .30
6.20 Line-to-line sustained short-circuit test .30
6.21 Sudden line-to-line short-circuit .31
6.22 Line-to-line and to neutral sustained short-circuit test.31
6.23 Negative-phase sequence test .32
6.24 Field current decay test, with the armature winding open-circuited .32
6.24.1 Test at rated speed .32
6.24.2 Test at standstill .32
6.25 Field current decay test at rated speed with the armature-winding short-
circuited .32
6.26 Suddenly applied excitation with armature winding short-circuited .33

60034-4 © IEC:2008 – 3 –
6.27 Field current decay test at standstill with two phases of armature winding
short-circuited .33
6.28 Applied voltage test with rotor removed .33
6.29 No-load retardation test.34
6.30 Suspended rotor oscillation test .34
6.31 Locked rotor test .35
6.32 Over-excitation test at zero power factor and variable armature voltage .35
6.33 Asynchronous operation during the low-voltage test .35
6.34 Applied variable frequency voltage test at standstill.36
7 Determination of quantities.38
7.1 Graphic procedures and analysis of oscillographic records.38
7.1.1 No-load saturation and three-phase, sustained short-circuit curves .38
7.1.2 Sudden three-phase short-circuit test .38
7.1.3 Voltage recovery test.41
7.1.4 Direct current decay in the armature winding at standstill .41
7.1.5 Suddenly applied excitation test with armature winding open-circuited .43
7.2 Direct-axis synchronous reactance .44
7.2.1 From no-load saturation and three-phase sustained short-circuit test .44
7.2.2 From motor no-load test .44
7.2.3 From phase shifting test .44
7.2.4 From on-load test measuring the load angle .44
7.3 Direct-axis transient reactance .45
7.3.1 From sudden three-phase short-circuit test.45
7.3.2 From voltage recovery test .45
7.3.3 From d.c. decay test in the armature winding at standstill .45
7.3.4 Calculation from test values.45
7.4 Direct-axis sub-transient reactance .45
7.4.1 From sudden three-phase short-circuit test.45
7.4.2 From voltage recovery test .46
7.4.3 From applied voltage test with the rotor in direct and quadrature axis.46
7.4.4 From applied voltage test with the rotor in arbitrary position .46
7.5 Quadrature-axis synchronous reactance.47
7.5.1 From negative excitation test.47
7.5.2 From low slip test .47
7.5.3 From phase shifting test .48
7.5.4 From on-load test measuring the load angle .49
7.6 Quadrature-axis transient reactance.49
7.6.1 From direct current decay test in the armature winding at standstill .49
7.6.2 Calculation from test values.49
7.7 Quadrature-axis sub-transient reactance .49
7.7.1 From applied voltage test with the rotor in direct and quadrature
position .49
7.7.2 From applied voltage test with the rotor in arbitrary position .50
7.8 Zero-sequence reactance.50
7.8.1 From single-phase voltage application to the three phases .50
7.8.2 From line-to-line and to neutral sustained short-circuit test .50
7.9 Negative-sequence reactance .51
7.9.1 From line-to-line sustained short-circuit test .51
7.9.2 From negative-phase sequence test .51

– 4 – 60034-4 © IEC:2008
7.9.3 Calculation from test values.52
7.9.4 From sudden line-to-line short-circuit test .52
7.9.5 From direct-current decay test at standstill .52
7.10 Armature leakage reactance.52
7.11 Potier reactance .53
7.12 Zero-sequence resistance .54
7.12.1 From single-phase voltage test applied to the three phases.54
7.12.2 From line-to-line and to neutral sustained short-circuit test .54
7.13 Positive-sequence armature winding resistance .54
7.14 Negative-sequence resistance.54
7.14.1 From line-to-line sustained short-circuit test .54
7.14.2 From negative-phase sequence test .55
7.15 Armature and excitation winding resistance.55
7.16 Direct-axis transient short-circuit time constant .56
7.16.1 From sudden three-phase short-circuit test.56
7.16.2 From field current decay at rated speed with armature winding short-
circuited .56
7.16.3 From direct current decay test at standstill .56
7.16.4 From suddenly applied excitation with armature winding short-
circuited .56
7.16.5 From field current decay test at standstill with two phases of
armature winding short-circuited.56
7.17 Direct-axis transient open-circuit time constant .56
7.17.1 From field current decay at rated speed with armature winding open .56
7.17.2 From field current decay test at standstill with armature winding open .56
7.17.3 From voltage recovery test .56
7.17.4 From direct-current decay test at standstill .57
7.17.5 From suddenly applied excitation with armature winding open-
circuited .57
7.18 Direct-axis sub-transient short-circuit time constant.57
7.19 Direct-axis sub-transient open-circuit time constant.57
7.19.1 From voltage recovery test .57
7.19.2 From direct-current decay test at standstill .57
7.20 Quadrature-axis transient short-circuit time constant .57
7.20.1 Calculation from test values.57
7.20.2 From direct-current decay test at standstill .57
7.21 Quadrature-axis transient open-circuit time constant .57
7.21.1 Determination from direct-current decay test at standstill.57
7.22 Quadrature-axis sub-transient short-circuit time constant .57
7.22.1 Calculation from test values.57
7.22.2 Determination from direct- current decay test at standstill.58
7.23 Quadrature-axis sub-transient open-circuit time constant .58
7.23.1 From direct-current decay test at standstill .58
7.24 Armature short-circuit time constant .58
7.24.1 From sudden three-phase short-circuit test.58
7.24.2 Calculation from test values.58
7.25 Rated acceleration time and stored energy constant.58
7.25.1 From suspended rotor oscillation test .58
7.25.2 From no-load retardation test .59

60034-4 © IEC:2008 – 5 –
7.26 Rated excitation current .59
7.26.1 From direct measurement.59
7.26.2 Potier diagram .60
7.26.3 ASA diagram .61
7.26.4 Swedish diagram .62
7.27 Excitation current referred to rated armature sustained short-circuit current .63
7.27.1 From over-excitation test at zero power factor .63
7.27.2 From sustained three-phase short-circuit test .64
7.28 Frequency response characteristics .64
7.28.1 General .64
7.28.2 From asynchronous operation at reduced voltage.64
7.28.3 From applied variable frequency voltage test at standstill .65
7.28.4 From direct current decay test in the armature winding at standstill .66
7.29 Short-circuit ratio.67
7.30 Rated voltage regulation.67
7.30.1 From direct measurement.67
7.30.2 From no-load saturation characteristic and known field current at
rated load .67
7.31 Initial starting impedance of synchronous motors .67
Annex A (informative) Testing cross-reference.69
Annex B (informative) Calculation scheme for frequency response characteristics .72
Annex C (informative) Conventional electrical machine model .74

Figure 1 – Schematic for d.c. decay test at standstill .28
Figure 2 – Circuit diagram for line-to-line short-circuit test .30
Figure 3 – Circuit diagram for line-to-line and to neutral sustained short-circuit test.31
Figure 4 – Search coil installation with rotor removed .34
Figure 5 – Power and current versus slip (example).36
Figure 6 – Schematic for variable frequency test at standstill.36
Figure 7 – Recorded quantities from variable frequency test at standstill (example).37
Figure 8 – Combined saturation and short-circuit curves.38
Figure 9 – Transient and sub-transient component of short-circuit current .39
Figure 10 – Determination of transient component of short-circuit current .40
Figure 11 – Graphical determination of aperiodic component .40
Figure 12 – Transient and sub-transient component of recovery voltage .41
Figure 13 – Semi-logarithmic plot of decay currents.42
Figure 14 – Suddenly applied excitation with armature winding open-circuited.43
Figure 15 – No-load e.m.f. and excitation current for one pole-pitch slip .47
Figure 16 – Current envelope from low-slip test .48
Figure 17 – Determination of Potier reactance .53
Figure 18 – Potier's diagram .60
Figure 19 – ASA diagram.61
Figure 20 – Swedish diagram.62
Figure 21 – Excitation current from over-excitation at zero power factor .63
Figure 22 – Frequency response characteristics at low frequencies (example).65

– 6 – 60034-4 © IEC:2008
Figure C.1 – Equivalent circuit model of a salient pole machine .74

Table 1 – Test methods and cross-reference table.16
Table A.1 – Test cross-reference .69

60034-4 © IEC:2008 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –

Part 4: Methods for determining synchronous
machine quantities from tests
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 60034-4 has been prepared by IEC technical committee 2:
Rotating machinery.
This third edition cancels and replaces the second edition published in 1985 and its
amendment 1 (1995). This edition constitutes a technical revision. The main changes with
respect to the previous edition are listed below:
– Tests described in Supplement A of the previous edition were partly removed for lack of
relevance in current practise.
– Provisions were made for tests on machines with brushless excitation.
– A table of test methods indicates preferred tests, and a test cross-reference is provided.
– The conventional two-axes salient-pole machine model description was added in an
Annex.
– 8 – 60034-4 © IEC:2008
The text of this standard is based on the following documents:
FDIS Report on voting
2/1488/FDIS 2/1495/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.
A list of all parts of IEC 60034 series, under the general title Rotating electrical machines, can
be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
60034-4 © IEC:2008 – 9 –
ROTATING ELECTRICAL MACHINES –

Part 4: Methods for determining synchronous
machine quantities from tests
1 Scope
This part of IEC 60034 applies to three-phase synchronous machines of 1 kVA rating and
larger with rated frequency of not greater than 500 Hz and not less than 10 Hz.
Most of the methods are intended to be used for machines having an excitation winding with
slip-rings and brushes for their supply. Synchronous machines with brushless excitation
require special effort for some of the tests. For machines with permanent magnet excitation,
there is a limited applicability of the described tests, and special precautions have to be taken
against irreversible demagnetization.
Excluded are axial-field machines and special synchronous machines such as inductor type
machines and transversal flux machines.
It is not intended that this standard be interpreted as requiring any or all of the tests described
therein on any given machine. The particular tests to be carried out shall be subject to
agreement between manufacturer and customer.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60034-1:2004, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-2-1, Rotating electrical machines – Part 2-1: Standards methods for determining
losses and efficiency from tests (excluding machines for traction vehicles)
IEC 60034-2A, Rotating electrical machines – Part 2: Methods for determining losses and
efficiency from tests (excluding machines for traction vehicles) – First supplement:
Measurement of losses by the calorimetric method
IEC 60051 (all parts), Direct acting indicating analogue electrical measuring instruments and
their accessories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
initial starting impedance, synchronous motors
quotient of the applied armature voltage and the sustained average armature current, the
machine being at standstill
– 10 – 60034-4 © IEC:2008
3.2
direct-axis synchronous reactance
the quotient of the sustained value of that fundamental a.c. component of armature voltage,
which is produced by the total direct-axis primary flux due to direct-axis armature current, and
the value of the fundamental a.c. component of this current, the machine running at rated
speed
[IEV 411-50-07]
3.3
direct-axis transient reactance
the quotient of the initial value of a sudden change in that fundamental a.c. component of
armature voltage, which is produced by the total direct-axis primary flux, and the value of the
simultaneous change in fundamental a.c. component of direct-axis armature current, the
machine running at rated speed and the high decrement components during the first cycles
being excluded
[IEV 411-50-09]
3.4
direct-axis sub-transient reactance
the quotient of the initial value of a sudden change in that fundamental a.c. component of
armature voltage, which is produced by the total direct-axis armature flux, and the value of
the simultaneous change in fundamental a.c. component of direct-axis armature current, the
machine running at rated speed
[IEV 411-50-11]
3.5
quadrature-axis synchronous reactance
the quotient of the sustained value of that fundamental a.c. component of armature voltage,
which is produced by the total quadrature-axis primary flux due to quadrature-axis armature
current, and the value of the fundamental a.c. component of this current, the machine running
at rated speed
[IEV 411-50-08]
3.6
quadrature-axis transient reactance
the quotient of the initial value of a sudden change in that fundamental a.c. component of
armature voltage, which is produced by the total quadrature-axis armature winding flux, and
the value of the simultaneous change in fundamental a.c. component of quadrature-axis
armature current, the machine running at rated speed and the high decrement components
during the first cycles being excluded
[IEV 411-50-10]
3.7
quadrature-axis sub-transient reactance
the quotient of the initial value of a sudden change in that fundamental a.c. component of
armature voltage, which is produced by the total quadrature-axis primary flux and the value of
the simultaneous change in fundamental a.c. component of quadrature-axis armature current,
the machine running at rated speed
[IEV 411-50-12]
3.8
positive sequence reactance
the quotient of the reactive fundamental component of the positive sequence armature
voltage, due to the sinusoidal positive sequence armature current at rated frequency, by the
value of that component of current, the machine running at rated speed
[IEV 411-50-14]
60034-4 © IEC:2008 – 11 –
3.9
negative sequence reactance
the quotient of the reactive fundamental component of negative sequence armature voltage,
due to the sinusoidal negative sequence armature current at rated frequency, by the value of
that component of current, the machine running at rated speed
[IEV 411-50-15]
3.10
zero sequence reactance
the quotient of the reactive fundamental component of zero sequence armature voltage, due
to the presence of fundamental zero sequence armature current at rated frequency, by the
value of that component of current, the machine running at rated speed
[IEV 411-50-16]
3.11
Potier reactance
a reactance taking into account the leakage of the field winding, on load and in the over-
excited region, which is used in place of the armature leakage reactance to calculate the
excitation on load by means of the Potier method
[IEV 411-50-13]
3.12
armature-leakage reactance
quotient of the reactive fundamental component of armature voltage due to the leakage flux of
armature winding and the fundamental component of armature current, the machine running
at rated speed
3.13
armature resistance
resistance measured by direct current between terminals of the armature winding, assigned to
a certain winding temperature, expressed as per phase value
3.14
excitation winding resistance
resistance measured by direct current between terminals of the excitation winding, assigned
to a certain winding temperature
3.15
positive sequence resistance
the quotient of the in-phase component of positive sequence armature voltage corresponding
to losses in the armature winding and stray load losses due to the sinusoidal positive
sequence armature current, by the value of that component of current, the machine running at
rated speed
[IEV 411-50-18]
3.16
negative sequence resistance
the quotient of the in-phase fundamental component of negative sequence armature voltage,
due to the sinusoidal negative sequence armature current at rated frequency, by the value of
that component of current, the machine running at rated speed
[IEV 411-50-19]
3.17
zero sequence resistance
the quotient of the in-phase fundamental component of zero sequence armature voltage, due
to the fundamental zero sequence armature current of rated frequency, by the value of that
component of current, the machine running at rated speed

– 12 – 60034-4 © IEC:2008
[IEV 411-50-20]
3.18
short-circuit ratio
the ratio of the field current for rated armature voltage on open-circuit to the field current for
rated armature current on sustained symmetrical short-circuit, both with the machine running
at rated speed
[IEV 411-50-21]
3.19
direct-axis transient open-circuit time constant
the time required, following a sudden change in operating conditions, for the slowly changing
component of the open-circuit armature voltage, which is due to direct-axis flux, to decrease
to 1/e , that is 0,368 of its initial value, the machine running at rated speed
[IEV 411-48-27]
3.20
direct-axis transient short-circuit time constant
the time required, following a sudden change in operating conditions, for the slowly changing
component of direct-axis short-circuit armature current to decrease to 1/e, that is 0,368 of its
initial value, the machine running at rated speed
[IEV 411-48-28]
3.21
direct-axis sub-transient open-circuit time constant
the time required, following a sudden change in operating conditions, for the rapidly changing
component present during the first few cycles of the open-circuit armature winding voltage
which is due to direct-axis flux, to decrease to 1/e, that is 0,368 of its initial value, the
machine running at rated speed
[IEV 411-48-29]
3.22
direct-axis sub-transient short-circuit time constant
the time required, following a sudden change in operating conditions, for the rapidly changing
component, present during the first few cycles in the direct-axis short-circuit armature current,
to decrease to 1/e, that is 0,368 of its initial value, the machine running at rated speed
[IEV 411-48-30]
3.23
quadrature-axis transient open-circuit time constant
the time required, following a sudden change in operating conditions, for the slowly changing
component of the open-circuit armature winding voltage which is due to quadrature-axis flux,
to decrease to 1/e, that is 0,368 of its initial value, the machine running at rated speed
[IEV 411-48-32]
3.24
quadrature-axis transient short-circuit time constant
the time required, following a sudden change in operating conditions, for the slowly changing
component of quadrature-axis short-circuit armature winding current, to decrease to
1/e, that is 0,368 of its initial value, the machine running at rated speed
[IEV 411-48-33]
60034-4 © IEC:2008 – 13 –
3.25
quadrature-axis sub-transient open-circuit time constant
the time required, following a sudden change in operating conditions, for the rapidly changing
component of the open-circuit armature winding voltage which is due to quadrature-axis flux,
to decrease to 1/e, that is 0,368 of its initial value, the machine running at rated speed
[IEV 411-48-34]
3.26
direct-axis open-circuit equivalent damper circuit time constant
time required for the induced current component in the equivalent damper circuit to decrease
to 1/e ≈ 0,368 of its initial value following a sudden change in operating conditions with open-
circuited armature winding and the excitation winding being also open, the machine running at
rated speed
3.27
direct-axis short-circuit equivalent damper winding time constant
time required for the induced current component of the equivalent damper winding to
decrease to 1/e ≈ 0,368 of its initial value following a sudden change in operating conditions
with short-circuited armature winding the excitation winding being open, and the machine
running at rated speed
3.28
quadrature-axis sub-transient short-circuit time constant
the time required, following a sudden change in operating conditions, for the rapidly changing
component present during the first few cycles in the quadrature-axis short-circuit armature
winding current, to decrease to 1/e, that is 0,368 of its initial value, the machine running at
rated speed
[IEV 411-48-35]
3.29
short-circuit time constant of armature windings
the time required, following a sudden change in operating conditions, for the d.c. component
present in the short-circuit armature winding current, to decrease to 1/e, that is 0,368 of its
initial value, the machine running at rated speed
[IEV 411-48-31]
3.30
unit acceleration time
the time which would be required to bring the rotating parts of a machine from rest to rated
speed if th
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