EN 60034-3:2005

SLOVENSKI SIST EN 60034-3:2006

STANDARD
januar 2006
Rotacijski električni stroji – 3. del: Posebne zahteve za sinhronske stroje s
cilindričnim rotorjem (IEC 60034-3:2005)
(istoveten EN 60034-3:2005)
Rotating electrical machines – Part 3: Specific requirements for cylindrical rotor
synchronous machines (IEC 60034-3:2005)
ICS 29.160.20 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 60034-3
NORME EUROPÉENNE
EUROPÄISCHE NORM June 2005
ICS 29.160 Supersedes EN 60034-3:1995

English version
Rotating electrical machines
Part 3: Specific requirements for cylindrical
rotor synchronous machines
(IEC 60034-3:2005)
Machines électriques tournantes Drehende elektrische Maschinen
Partie 3: Règles spécifiques Teil 3: Besondere Anforderungen
pour les machines synchrones an Vollpol-Synchronmaschinen
à rotor cylindrique (IEC 60034-3:2005)
(CEI 60034-3:2005)
This European Standard was approved by CENELEC on 2005-05-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and 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

© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60034-3:2005 E
Foreword
The text of document 2/1315/FDIS, future edition 5 of IEC 60034-3, prepared by IEC TC 2, Rotating
machinery, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 60034-3 on 2005-05-01.
This European Standard supersedes EN 60034-3:1995.
The significant technical changes with respect to EN 60034-3:1995 are as follows:
– the document has been consolidated and completely restructured. It was rewritten to a
considerable extent;
– the section on air cooled generators has been combined with that on hydrogen-cooled and liquid
cooled generators. Different requirements so far valid for air cooled generators alone were
modified in such a way that the requirements are now strictly bound to the generator ratings but
not longer to the machine type. As an example for the harmonisation which took place the short
circuit ratio of the air cooled generators were adjusted to those for the other generators. The
separate cooler sections for air cooled generators were eliminated;
– the standard was generally adjusted to the progress in generator control. The state of the art
control systems do not require the previous large power factors. They were reduced to one
minimum value instead of several value classes providing the prospects of reduced generator
costs. It was considered that standards should not work as an unnecessary cost driving factor;
– a normative Annex A has been added dealing with precautions to be taken when using hydrogen
as a coolant on turbine–type synchronous generators. Formerly only a guide was provided. It was
considered that aspects dealing with the safe operation of hydrogen cooled generators must be
taken seriously and must become normative.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-02-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-05-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60034-3:2005 approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60034-8 NOTE Harmonized as EN 60034-8:2002 (not modified).
__________
- 3 - EN 60034-3:2005
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 Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60034-1 - Rotating electrical machines EN 60034-1 2004
Part 1: Rating and performance

1) 2)
IEC 60034-4 - Part 4: Methods for determining EN 60034-4 1995
(mod) synchronous machine quantities from
tests
1) 2)
IEC 60045-1 - Steam turbines EN 60045-1 1993
Part 1: Specifications
IEC 60079 (mod) Series Electrical apparatus for explosive gas EN 60079 Series
atmospheres
1)
Undated reference.
2)
Valid edition at date of issue.

NORME CEI
INTERNATIONALE IEC
60034-3
INTERNATIONAL
Cinquième édition
STANDARD
Fifth edition
2005-02
Machines électriques tournantes –
Partie 3:
Règles spécifiques pour les machines
synchrones à rotor cylindrique

Rotating electrical machines –
Part 3:
Specific requirements for cylindrical rotor
synchronous machines
 IEC 2005 Droits de reproduction réservés  Copyright - all rights reserved
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Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

60034-3  IEC:2005 – 3 –
CONTENTS
FOREWORD.7

1 Scope .13
2 Normative references .13
3 Terms and definitions .13
4 General .15
4.1 General rules.15
4.2 Rated conditions.15
4.3 Rated voltage .15
4.4 Power factor .15
4.5 Rated speed.15
4.6 Ranges of voltage and frequency .17
4.7 Direction of rotation .19
4.8 Stator winding .19
4.9 Machine rated field current and voltage.19
4.10 Machine insulation.19
4.10.1 Thermal class .19
4.10.2 Withstand voltage tests .19
4.11 Insulation against shaft current .19
4.12 Over-speed test.21
4.13 Critical-speeds .21
4.14 P-Q capability diagram .21
4.15 Overcurrent requirements .23
4.16 Sudden short circuit.25
4.17 Short-circuit ratio .25
4.18 Direct axis transient and subtransient reactances for generators.25
4.19 Tolerances on short-circuit ratio and direct axis transient and subtransient
reactances .27
4.20 Mechanical conditions for rotors.27
4.20.1 Number of starts .27
4.20.2 Turning gear operation.27
4.21 Coolers .27
5 Air-cooled machines .29
5.1 General .29
5.2 Machine cooling .29
5.3 Temperature of primary coolant .29
5.3.1 Temperature detectors .29
6 Hydrogen-cooled or liquid-cooled machines .31
6.1 General .31
6.2 Hydrogen pressure and purity in the casing.31
6.3 Machine housing and cover plates .31
6.4 Stator winding terminals .31
6.5 Temperature of primary coolants, temperatures and temperature rises of the
machine .31

60034-3  IEC:2005 – 5 –
6.6 Temperature detectors.33
6.7 Auxiliary system .33
7 Machines for combustion gas turbines or combined cycle applications .35
7.1 General .35
7.2 Service conditions .35
7.2.1 General .35
7.2.2 Primary coolant temperature .35
7.2.3 Number of starts .37
7.2.4 Application of load .37
7.3 Rated output.37
7.4 Capabilities .37
7.4.1 General .37
7.4.2 Base capability .37
7.4.3 Temperature rise and temperature at base capability .41
7.4.4 Peak capability .41
7.5 Rating plate.41
7.6 Temperature tests .41
7.7 Operation as a synchronous compensator .41

Annex A (normative) Precautions to be taken when using hydrogen cooled turbine-
type synchronous machines .43

Bibliography .57

Figure 1 – Operation over ranges of voltage and frequency .17
Figure 2 – Typical P-Q capability diagram .23
Figure 3 – Typical generator capability curves .39
Figure A.1 – Example of a large hydrogen supply unit feeding one or more generators
(simplified diagram) .55

60034-3  IEC:2005 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ROTATING ELECTRICAL MACHINES –

Part 3: Specific requirements for cylindrical rotor
synchronous machines
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 60034-3 has been prepared by IEC Technical Committee 2:
Rotating machinery.
This fifth edition cancels and replaces the fourth edition published in 1988. This edition
constitutes a technical revision. The significant technical changes with respect to the previous
edition are as follows:
• the document has been consolidated and completely restructured. It was rewritten to a
considerable extent;
• the section on air cooled generators has been combined with that on hydrogen-cooled and
liquid cooled generators. Different requirements so far valid for air cooled generators
alone were modified in such a way that the requirements are now strictly bound to the
generator ratings but not longer to the machine type. As an example for the harmonisation
which took place the short circuit ratio of the air cooled generators were adjusted to those
for the other generators. The separate cooler sections for air cooled generators were
eliminated;
60034-3  IEC:2005 – 9 –
• the standard was generally adjusted to the progress in generator control. The state of the
art control systems do not require the previous large power factors. They were reduced to
one minimum value instead of several value classes providing the prospects of reduced
generator costs. It was considered that the standards should not work as an unnecessary
cost driving factor;
• a normative Annex A has been added dealing with precautions to be taken when using
hydrogen as a coolant on turbine – type synchronous generators. Formerly only a guide
was provided. It was considered that aspects dealing with the safe operation of hydrogen
cooled generators must be taken seriously and must become normative.
The text of this standard is based on the following documents:
FDIS Report on voting
2/1315/FDIS 2/1326/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.
IEC 60034 consists of the following parts, under the general title Rotating electrical machines:
Part 1: Rating and performance
Part 2: Methods for determining losses and efficiency of rotating electrical machinery
from tests (excluding machines for traction vehicles)
Part 3: Specific requirements for cylindrical rotor synchronous machines (this
publication)
Part 4: Methods for determining synchronous machine quantities from tests
Part 5: Degrees of protection provided by the integral design of rotating electrical
machines (IP code) – Classification
Part 6: Methods of cooling (IC Code)
Part 7: Classification of types of construction, mounting arrangements and terminal
box position (IM Code)
Part 8: Terminal markings and direction of rotation
Part 9: Noise limits
Part 11: Thermal protection
Part 12: Starting performance of single-speed three-phase cage induction motors
Part 14: Mechanical vibration of certain machines with shaft heights 56 mm and higher
– Measurement, evaluation and limits of vibration severity
Part 15: Impulse voltage withstand levels of rotating a.c. machines with form-wound
stator coils
Part 16: Excitation systems for synchronous machines
Part 17: Cage induction motors when fed from converters – Application guide
Part 18: Functional evaluation of insulation systems
Part 19: Specific test methods for d.c. machines on conventional and rectifier-fed
supplies
60034-3  IEC:2005 – 11 –
Part 20-1: Control motors – Stepping motors
Part 22: AC generators for reciprocating internal combustion (RIC) engine driven
generating sets
Part 23: Specification for the refurbishing of rotating electrical machines
Part 25: Guide for the design and performance of cage induction motors specifically
designed for converter supply
Part 26: Effects of unbalanced voltages on the performance of three-phase induction
motors
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.
60034-3  IEC:2005 – 13 –
ROTATING ELECTRICAL MACHINES –

Part 3: Specific requirements for cylindrical rotor
synchronous machines
1 Scope
This part of IEC 60034 applies to three-phase cylindrical rotor synchronous machines, having
rated outputs of 10 MVA (or MW) and above. It supplements the basic requirements for
rotating machines given in IEC 60034-1. The special requirements of machines continuously
fed by inverters are not covered by this standard.
Common requirements for all cylindrical rotor machines are prescribed together with specific
requirements for air, for hydrogen or for liquid cooled cylindrical rotor synchronous machines.
This part of IEC 60034 also gives the precautions to be taken when using hydrogen cooled
machines including
– rotating exciters driven by cylindrical rotor type machines;
– auxiliary equipment needed for operating the machines;
– parts of the building where hydrogen might accumulate.
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, Rotating electrical machines – Part 1: Rating and performance
IEC 60034-4, Rotating electrical machines – Part 4: Methods for determining synchronous
machine quantities from tests
IEC 60045-1, Steam turbines – Part 1: Specifications
IEC 60079 (all parts), Electrical apparatus for explosive gas atmospheres
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC 60034-1 together with the
following additions apply.
3.1
mechanical start
change in speed from zero or turning gear speed to rated speed

60034-3  IEC:2005 – 15 –
3.2
turning gear operation
rotation at low speed to maintain thermal equilibrium of the steam turbine and/or rotor
4 General
4.1 General rules
Cylindrical rotor machines shall be in accordance with the basic requirements for rotating
machines specified in IEC 60034-1 unless otherwise specified in this standard. Wherever in
this standard there is reference to an agreement, it shall be understood that this is an
agreement between the manufacturer and the purchaser.
4.2 Rated conditions
The rated conditions are given by the rated values of
– the apparent power for generators and compensators or the power at the shaft end for
motors;
– frequency;
– voltage;
– power factor;
– primary coolant temperature (40°C unless otherwise agreed upon);
and where applicable,
– site altitude;
– hydrogen pressure;
– range of hydrogen purity, see IEC 60034-1.
4.3 Rated voltage
The rated voltage shall be fixed by agreement.
4.4 Power factor
The power factor shall be agreed upon between the purchaser and manufacturer.
Standardised rated power factors at the generator terminals are 0,8, 0,85 and 0,9 overexcited.
Preferred power factors of motors are 0,95 overexcited and 1,0.
NOTE 1 Other values may be agreed upon, the lower the power factor the larger will be the machine.
NOTE 2 It is recommended that the generator should be capable of providing 0,95 underexcited power factor at
rated MVA.
4.5 Rated speed
The rated speed shall be
–1 –1
1 500 min or 3 000 min for 50 Hz machines;
–1 –1
1 800 min or 3 600 min for 60 Hz machines.
In cases of cylindrical rotor synchronous motors with six poles the speeds shall be
–1 –1
1 000 min for 50 Hz and 1 200 min for 60 Hz machines.

60034-3  IEC:2005 – 17 –
4.6 Ranges of voltage and frequency
Machines shall be capable of continuous rated output at the rated power factor over the
ranges of ±5 % in voltage and ±2 % in frequency, as defined by the shaded area of Figure 1.
The temperature rise limits in Tables 7 and 8, or the temperature limits in Table 12 of
IEC 60034-1 shall apply at the rated voltage and frequency only.
NOTE 1 As the operating point moves away from the rated values of voltage and frequency, the temperature rise
or total temperatures may progressively increase. Continuous operation at rated output at certain parts of the
boundary of the shaded area causes temperature rises to increase by up to 10 K approximately. Machines will also
+3
carry output at rated power factor within the ranges of ±5 % in voltage and % in frequency, as defined by the
−5
outer boundary of Figure 1, but temperature rises will be further increased. Therefore, to minimize the reduction of
the machine's lifetime due to the effects of temperature or temperature differences, operation outside the shaded
area should be limited in extent, duration and frequency of occurrence. The output should be reduced or other
corrective measures taken as soon as practicable.
If an operation over a still wider range of voltage or frequency or deviations from rated
frequency and voltage of generators for combustion gas turbine application at peak load are
required, this should be the subject of an agreement.
NOTE 2 It is considered that overvoltage together with low frequency, or low voltage with over-frequency, are
unlikely operating conditions. The former is the condition most likely to increase the temperature rise of the field
winding. Figure 1 shows operation in these quadrants restricted to conditions that will cause the machine and its
transformer to be over- or under-fluxed by no more than 5 %. Margins of excitation and of stability will be reduced
under some of the operating conditions shown. As the operating frequency moves away from the rated frequency,
effects outside the generator may become important and need to be considered. As examples: the turbine
manufacturer will specify ranges of frequency and corresponding periods during which the turbine can operate; and
the ability of auxiliary equipment to operate over a range of voltage and frequency should be considered.
V %
f %
95 98 100 102 103
IEC  082/05
(See 4.6 for conditions relating to operation over the voltage and frequency shown above.)
Figure 1 – Operation over ranges of voltage and frequency

60034-3  IEC:2005 – 19 –
4.7 Direction of rotation
The generator has only one direction of rotation, which is determined by the driven or driving
machine. The direction of rotation shall be shown on the generator or on its rating plate, and
the time-phase sequence of the stator voltage shall then be indicated by marking the
terminals in the sequence in which their voltages reach maximum, for example, U , V , W .
1 1 1
Synchronous motors are commonly designed for an operation in both directions of rotation.
NOTE Terminal markings may not be consistent with IEC 60034-8.
For machines having one driving end, this shall be the reference end for the direction of
rotation.
For machines having two drive ends, the more powerful drive end shall be the reference end.
If not applicable, the end opposite to the excitation leads shall be the reference end for the
direction of rotation.
The sense of rotation (clockwise or counter-clockwise) shall be defined when facing the
generator rotor coupling from the reference side.
4.8 Stator winding
Unless otherwise agreed upon, rated machine voltage corresponds to star connection. On
generators all winding ends shall be brought out and arranged in an agreed arrangement of
the external connections to the machine.
4.9 Machine rated field current and voltage
The machine rated field current and voltage are those values needed for the machine to
operate at rated conditions.
4.10 Machine insulation
4.10.1 Thermal class
Insulation systems used for the windings shall be of thermal class 130 or higher.
4.10.2 Withstand voltage tests
Withstand voltage tests shall be in accordance with IEC 60034-1, Table 16.
4.11 Insulation against shaft current
Suitable precautions shall be taken to prevent harmful flow of shaft current and to earth the
rotor shaft adequately. Any insulation needed shall preferably be arranged so that it can be
measured while the machine is operating. Shaft voltage spikes caused by static excitation
with controlled rectifiers shall be kept down by suitable means to non-critical values. These
spikes could cause damage, for example, in the bearing lubrication film.

60034-3  IEC:2005 – 21 –
4.12 Over-speed test
Rotors of cylindrical rotor machines shall be tested at 1,2 times rated speed for 2 min.
4.13 Critical speeds
Critical speeds of the combined shaft train shall not cause unsatisfactory operation within the
speed range corresponding to the frequency range agreed upon in accordance with 4.6, see
also IEC 60045-1.
4.14 P-Q capability diagram
The manufacturer shall supply a P-Q capability diagram indicating the limits of operation. The
P-Q diagram shall be drawn for operation at rated conditions. A typical P-Q diagram is shown
in Figure 2, its boundaries are set by the following limitations:
– curve A represents operation with constant rated field current and therefore with
approximately constant temperature rise of the field winding;
– curve B represents constant rated stator current and consequently approximately constant
temperature rise of the stator winding;
– curve C indicates the limit set by localized end region heating, or by steady-state stability,
or by a combination of both effects.
NOTE 1 Figure 2 may contain other operational limits such as maximum turbine limits and minimum excitation
limits.
By agreement between the manufacturer and the purchaser, other diagrams may be provided
for operation at agreed upon conditions within the voltage and frequency ranges agreed upon
in accordance with 4.6, and for cooling and temperature conditions and where applicable
hydrogen pressures other than rated.
NOTE 2 The generator should be operated within the boundaries of the diagram appropriate to the chosen
conditions of voltage, frequency and cooling, and hydrogen pressure if applicable. Operation outside these
boundaries will shorten the life of the machine.
NOTE 3 For a machine with a water cooled stator winding at reduced hydrogen pressure, the maximum water
pressure within the winding can become higher than the hydrogen pressure. Hence, in the case of a leak, water
can move from the water circuit towards the hydrogen environment within the casing. This could cause failure.

60034-3  IEC:2005 – 23 –
Y A
0,8
D
0,6
0,4
B
0,2
X
0,2 0,4 0,6 0,8 1,0 1,2
0,2
0,4
0,6
0,8
C
Y'
IEC  083/05
Key
A limited by field winding temperature X  per unit kW
B limited by armature winding temperature Y  per unit kVAr lagging
C limited by the temperatures of the core end parts or by steady state Y'  per unit kVAr leading
stability
D rated output
Figure 2 – Typical P-Q capability diagram
4.15 Overcurrent requirements
Machines with rated outputs up to 1 200 MVA shall be able of carrying, without damage, a
stator current of 1,5 per unit (p.u.) for 30 s.
For ratings greater than 1 200 MVA, agreement should be reached on a time duration less
than 30 s, decreasing as the rating increases, to a minimum of 15 s, the current remaining at
1,5 per unit for all ratings.
The machine shall be capable of other combinations of overcurrent and time that give the
same degree of additional heat above that caused by 1 p.u. current.
Thus, for machines up to 1 200 MVA,
(I – 1)t = 37,5 s
where
I is the stator current per unit (p.u.);
t is its duration in seconds.
60034-3  IEC:2005 – 25 –
This relationship shall apply for values of t between 10 s and 60 s.
NOTE It is recognized that stator temperatures will exceed rated load values under these conditions, and
therefore the machine construction is based upon the assumption that the number of operations to the limit
conditions specified will not exceed two per year.
4.16 Sudden short circuit
The machine shall be designed to withstand without failure a short circuit of any kind at its
terminals, while operating at rated load and 1,05 p.u. rated voltage, provided the maximum
phase current is limited by external means to a value which does not exceed the maximum
phase current obtained from a three-phase short circuit. 'Without failure' means that the
machine shall not suffer damage that causes it to trip out of service, though some deformation
of the stator winding might occur.
If it is agreed upon between purchaser and manufacturer that a sudden short-circuit test shall
be made on a new machine, it shall be done after the full voltage dielectric acceptance test as
described below.
A machine that is to be connected directly to the system shall have a 3-phase short circuit
applied at its terminals when excited to rated voltage on no-load. For a machine that will be
connected to the system through its own transformer or reactor, usually by an isolated phase
bus, the test at the terminals shall be carried out at reduced voltage, agreed upon between
the purchaser and the manufacturer, in order to produce the same stator current as would
result in service from a three-phase short circuit applied at the high voltage terminals of the
transformer.
This test shall be considered satisfactory if the machine is subsequently judged to be fit for
service without repairs or with only minor repairs to its stator windings, and if it withstands a
high-voltage test of 80 % of the value specified in IEC 60034-1 for a new machine. The term
’minor repairs‘ implies some attention to end-winding bracing and to applied insulation, but
not replacement of coils.
NOTE Abnormal high currents and torques can occur as a result of a short circuit close to the generator in
service, or of clearance and re-closure of a more distant fault, or of faulty synchronizing. If such conditions do
actually impose severe overcurrents, it would be prudent to examine the machine thoroughly, with particular
attention to the stator windings. Any loosening of supports or packings should be made good before returning the
machine to service, to avoid the possibility of consequential damage being caused by vibration. It may also be
desirable to check for possible shaft balance changes and deformation of the coupling bolts and couplings.
4.17 Short-circuit ratio
For machines of all sizes and types of cooling covered by this standard, the value of the
short-circuit ratio at rated conditions shall be not less than 0,35. Higher minimum values may
be specified and agreed upon (for example by a grid demand), but, for a given cooling
system, these usually require an increase in machine size and higher losses.
4.18 Direct axis transient and subtransient reactances for generators
When the direct axis transient or subtransient reactances are specified having regard to the
operating conditions, the following values should be agreed upon:
– a minimum value of the direct axis subtransient reactance at the saturation level of rated
voltage;
– a maximum value of the direct axis transient reactance at the unsaturated conditions of
rated current.
60034-3  IEC:2005 – 27 –
Since the two reactances depend to a great extent on common fluxes, care should be taken to
ensure that the values specified and agreed upon are compatible, that is, that the upper limit
of the subtransient reactance is not set too close to the lower limit of the transient reactance.
When the value of the direct axis subtransient reactance is not specified, it shall be not less
than 0,1 p.u. at the saturation level corresponding to rated voltage.
The value of each of these reactances may be specified and agreed upon at another
saturation level in accordance with IEC 60034-4. If it is agreed that values are to be
determined by test, the test shall be in accordance with IEC 60034-4.
4.19 Tolerances on short-circuit ratio and direct axis transient and subtransient
reactances
Where the limit values of this standard, or other limits, have been specified or agreed upon,
there shall be no tolerance in the significant direction, that is, no negative tolerance on
minimum values and no positive tolerance on maximum values. In the other direction, a
tolerance of 30 % shall apply.
If values are specified but not declared to be limits, they shall be regarded as rated values,
and shall be subject to a tolerance of ±15 %.
Where no values have been specified by the purchaser, the manufacturer shall give values,
subject to a tolerance of ±15 %.
4.20 Mechanical conditions for rotors
4.20.1 Number of starts
Unless otherwise agreed upon, the rotor of a generator shall have a mechanical design
capable of withstanding during its lifetime:
– normally not less than 3 000 starts;
– for those designed for regular start-stop duties such as daily service not less than 10 000
starts.
4.20.2 Turning gear operation
Before start-up and after shut-down, turning gear operation of the turbine generator set may
be unavoidable primarily due to prime mover needs. However, prolonged turning gear
operation may make the generator rotor susceptible to damage and should be limited.
Susceptibility to turning gear operation damages can be influenced by the design. If a longer
turning gear operation is considered additional design efforts for minimising the harmful
effects should be the subject of an agreement.
4.21 Coolers
Unless otherwise agreed upon, coolers shall be suitable for cold water intake temperatures up
to 32 °C and a working pressure of not less than:
– 2,7 bar absolute (270 kPa) for air cooled machines;
– 4,5 bar absolute (450 kPa) for hydrogen and liquid cooled machines;
The test pressure shall be 1,5 times the maximum working pressure, and shall be applied for
15 min.
60034-3  IEC:2005 – 29 –
If the water pressure in the cooler is controlled by a valve or pressure-reducing device
connected to a water supply where the pressure is higher than the working pressure of the
cooler, the cooler shall be designed for the higher pressure, and tested at 1,5 times the higher
pressure value, unless otherwise agreed upon. This pressure shall be specified by the
purchaser.
Coolers shall be designed so that, if one section is intended to be taken out of service for
cleaning, the unit can carry at least two-thirds (or, by agreement, an other fraction) of rated
load continuously, without the permissible temperatures of the active parts of the machine
being exceeded. Under these conditions, the primary coolant temperature may be higher than
the design value. For hydrogen and liquid cooled machines, attention should be paid to the
fact that under some conditions of operation, for example, during maintenance or while
purging the casing of gas, a cooler might be subjected to gas pressure without water
pressure. It shall therefore be designed for a differential pressure of 8 bar (800 kPa) on the
gas side.
NOTE Increasing concentrations of chemicals in the water, for example salts or glycol can affect the cooling
performance.
5 Air-cooled machines
5.1 General
This clause applies to machines, the active parts of which are cooled by air, either directly or
indirectly or by a combination of the two methods.
5.2 Machine cooling
The system of ventilation should preferably be a closed air circuit system. If an open air
system is specified or agreed upon, care shall be taken to avoid contaminating the ventilation
passages with dirt, to avoid overheating and pollution of insulated surfaces.
When slip rings for excitation are provided, they should be ventilated separately to avoid
contaminating the generator and exciter with carbon dust.
5.3 Temperature of primary coolant
Machines other than those driven by gas turbines shall be in accordance with IEC 60034-1.
If the maximum temperature of the ambient air, or of the primary cooling air where an air-to-
water cooler is used, is other than 40°C, the relevant clauses of IEC 60034-1 apply.
Particular requirements for machines driven by gas turbines are given in 7.2 and 7.3.
5.3.1 Temperature detectors
In order to monitor the temperature of the stator winding, at least six embedded temperature
detectors (ETD) shall be supplied in accordance with IEC 60034-1.
The number of temperature detectors in the air intakes to the machine shall be agreed upon.

60034-3  IEC:2005 – 31 –
6 Hydrogen-cooled or liquid-cooled machines
6.1 General
This clause applies to machines the active parts of which are cooled directly or indirectly by
hydrogen, gas or liquid, or by a combination of both. Some machines may use a gas other
than hydrogen, if so, the same rules apply where appropriate.
6.2 Hydrogen pressure and purity in the cas
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