SIST EN 60609-1:2005

Hydraulic turbines, storage pumps and pump-turbines - Cavitation pitting evaluation -- Part 1: Evaluation in reaction turbines, storage pumps and pump-turbines

Provides a basis for the formulation of guarantees applied to cavitation pitting for reaction hydraulic turbines, storage pumps and pump-turbines. It addresses the measurement and evaluation of the amount of cavitation pitting on certain specified machine components for given conditions, which are defined in the contract by output, specific hydraulic energy (E), speed, material, operation, etc. The cavitation-pitting evaluation is based on the loss of material during a given time and under accurately defined operating conditions. All wetted surfaces are considered

Wasserturbinen, Speicherpumpen, Pumpenturbinen - Bewertung des Kavitationsangriffs -- Teil 1: Bewertung in Reaktionsturbinen, Speicherpumpen und Pumpenturbinen

Turbines hydrauliques, pompes d'accumulation et pompes-turbines - Evaluation de l'érosion de cavitation -- Partie 1: Evaluation dans les turbines à réaction, les pompes d'accumulation et les pompes-turbines hydrauliques

Fournit la base à l'établissement des garanties d'érosion de cavitation s'appliquant aux turbines hydrauliques à réaction, pompes d'accumulation et pompes-turbines. Elle traite de la mesure et de l'évaluation de l'importance de cette érosion sur divers composants d'une machine pour des conditions définies au contrat: puissance, énergie hydraulique massique (E), vitesse de rotation, nature des matériaux, conditions de fonctionnement, etc. Pour évaluer l'importance de l'étendue de l'érosion de cavitation on s'appuie sur la perte de matière pendant une période donnée et pour des conditions de fonctionnement définies avec précision. Toutes les surfaces en contact avec l'eau sont prises en compte.

Vodne turbine, akumulacijske črpalke in črpalne turbine – Ovrednotenje kavitacijskih razjed – 1. del: Ovrednotenje za reakcijske turbine, akumulacijske črpalke in črpalne turbine (IEC 60609-1:2004)

General Information

• Status: Published
• Publication Date: 31-Aug-2005
• ICS: 27.140 - Hydraulic energy engineering
• Technical Committee: IEHT - Electrotechnics - Hydraulic turbins
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Sep-2005
• Due Date: 01-Sep-2005
• Completion Date: 01-Sep-2005
• Ref Project: EN 60609-1:2005 - Hydraulic turbines, storage pumps and pump-turbines - Cavitation pitting evaluation - Part 1: Evaluation in reaction turbines, storage pumps and pump-turbines

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60609-1:2005
01-september-2005
9RGQHWXUELQHDNXPXODFLMVNHþUSDONHLQþUSDOQHWXUELQH±2YUHGQRWHQMH
NDYLWDFLMVNLKUD]MHG±GHO2YUHGQRWHQMH]DUHDNFLMVNHWXUELQHDNXPXODFLMVNH
þUSDONHLQþUSDOQHWXUELQH,(&
Hydraulic turbines, storage pumps and pump-turbines - Cavitation pitting evaluation --
Part 1: Evaluation in reaction turbines, storage pumps and pump-turbines
Wasserturbinen, Speicherpumpen, Pumpenturbinen - Bewertung des Kavitationsangriffs
-- Teil 1: Bewertung in Reaktionsturbinen, Speicherpumpen und Pumpenturbinen
Turbines hydrauliques, pompes d'accumulation et pompes-turbines - Evaluation de
l'érosion de cavitation -- Partie 1: Evaluation dans les turbines à réaction, les pompes
d'accumulation et les pompes-turbines hydrauliques
Ta slovenski standard je istoveten z: EN 60609-1:2005
ICS:
27.140 Vodna energija Hydraulic energy engineering
SIST EN 60609-1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60609-1:2005

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SIST EN 60609-1:2005
EUROPEAN STANDARD EN 60609-1
NORME EUROPÉENNE
EUROPÄISCHE NORM January 2005

ICS 23.100.10


English version


Hydraulic turbines, storage pumps and pump-turbines –
Cavitation pitting evaluation
Part 1: Evaluation in reaction turbines,
storage pumps and pump-turbines
(IEC 60609-1:2004)


Turbines hydrauliques, pompes Wasserturbinen, Speicherpumpen,
d'accumulation et pompes-turbines – Pumpenturbinen –
Evaluation de l'érosion de cavitation Bewertung des Kavitationsangriffs
Partie 1: Evaluation dans les turbines Teil 1: Bewertung in Reaktionsturbinen,
à réaction, les pompes d'accumulation Speicherpumpen und Pumpenturbinen
et les pompes-turbines hydrauliques (IEC 60609-1:2004)
(CEI 60609-1:2004)



This European Standard was approved by CENELEC on 2004-12-01. 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 60609-1:2005 E

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SIST EN 60609-1:2005
EN 60609-1:2005 - 2 -
Foreword
The text of document 4/196/FDIS, future edition 1 of IEC 60609-1, prepared by IEC TC 4, Hydraulic
turbines, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 60609-1 on 2004-12-01.
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) 2005-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-12-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60609-1:2004 was approved by CENELEC as a European
Standard without any modification.
__________

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SIST EN 60609-1:2005
- 3 - EN 60609-1:2005
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 60193 - Hydraulic turbines, storage pumps and EN 60193 1999
pump-turbines - Model acceptance tests

1)
IEC/TR 61366-1 - Hydraulic turbines, storage pumps and - -
pump-turbines - Tendering documents
Part 1: General and annexes



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

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SIST EN 60609-1:2005

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SIST EN 60609-1:2005
NORME CEI
INTERNATIONALE IEC
60609-1
INTERNATIONAL
Première édition
STANDARD
First edition
2004-11
Turbines hydrauliques, pompes d'accumulation
et pompes-turbines –
Evaluation de l'érosion de cavitation –
Partie 1:
Evaluation dans les turbines à réaction,
les pompes d'accumulation et les
pompes-turbines hydrauliques
Hydraulic turbines, storage pumps
and pump-turbines –
Cavitation pitting evaluation –
Part 1:
Evaluation in reaction turbines,
storage pumps and pump-turbines
© IEC 2004 Droits de reproduction réservés ⎯ Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
CODE PRIX
PRICE CODE S
Commission Electrotechnique Internationale
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 3 –
CONTENTS
FOREWORD.5
INTRODUCTION.9
1 Scope and object.13
1.1 Excluded topics and limitations.13
1.2 Considerations concerning chemical composition of water.13
1.3 Considerations concerning water containing solids .15
1.4 Normative references .15
2 Terms, definitions and symbols.15
2.1 Units .15
2.2 List of terms .17
3 Nature and extent of cavitation-pitting guarantees .25
3.1 Period of guarantee.25
3.2 Definition of the amount of cavitation pitting .25
3.3 Operating ranges and duration of operation.25
4 Procedures .29
4.1 Repair of cavitation pitting during the guarantee period .29
4.2 Measurement and calculation of the amount of cavitation pitting.31
5 Computation of results and fulfilment of the guarantee .33
Annex A (normative) Examples of amounts of cavitation pitting.35
Bibliography.41
Figure 1 – Amount of cavitation pitting as a function of σ for a given machine at constant
discharge.11
Figure 2 – Operating ranges for turbines and pump-turbines during turbine operation.21
Figure 3 – Operating ranges for storage pumps and pump-turbines during pump
operation .23
Figure A.1 – Examples of maximum permissible values of cavitation pitting depth for
runners/impellers .37
Figure A.2 – Examples of maximum permissible values of cavitation pitting volume for
runners/impellers .39

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
CAVITATION PITTING EVALUATION –
Part 1: Evaluation in reaction turbines, storage pumps
and pump-turbines
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 60609-1 has been prepared by IEC technical committee 4: Hydraulic
turbines.
This standard cancels and replaces IEC 60609, published in 1978, and constitutes a technical
revision. The main changes with respect to IEC 60609 pertain to tighter controls on reduced
permissible values of material loss. Modern technology with accumulated R&D has permitted
the integration of improved hydraulic design, better controls from numerical machining and
improved choice of materials.
The text of this standard is based on the following documents:
FDIS Report on voting
4/196/FDIS 4/200/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.

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60609 consists of the following parts, under the general title Cavitation pitting evaluation in
hydraulic turbines, storage pumps and pump-turbines:
Part 1: Evaluation in reaction turbines, storage pumps and pump-turbines
Part 2: Evaluation in Pelton turbines
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.

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 9 –
INTRODUCTION
This part of IEC 60609 covers the subject of cavitation-pitting evaluation for reaction type
hydraulic turbines, storage pumps and pump-turbines, while IEC 60609-2 covers the subject of
cavitation-pitting evaluation for impulse (Pelton) type turbines.
Guarantees applied to cavitation pitting in hydraulic reaction turbines, storage pumps and
pump-turbines are quite different from other performance guarantees stated in the contract
documents representing inherent characteristics of the machine, such as efficiency. The extent
of cavitation pitting depends essentially on five factors:
a) type and design of the machine;
b) material and surface condition of the parts subjected to cavitation;
c) setting of the machine, i.e. the cavitation factor sigma (σ) value at the plant;
d) duration of operation and type of operating conditions; and
e) water quality.
Items a) and b) describe the machine while items c), d) and e) depend on plant operating
conditions. Therefore, the guarantee for cavitation pitting can be established only by mutual
agreement between the employer and the contractor during the planning of the plant or during
the contract negotiations. Under certain severe conditions such as plant upgrades with
runner/impeller replacements or wide operating ranges, it may be to the advantage of the
employer to request that tenderers submit a guarantee to cover cavitation pitting in their
proposals.
A cavitation-pitting guarantee may be negotiated in two ways:
either the setting of the machine (and therefore the σ value of the plant) is given in the
contract documents, and the amount of the cavitation pitting is agreed upon with due
regard to the turbine or pump size, rotational speed, materials, surface conditions,
operation, etc. (see Figure 1a);
or the maximum amount of the cavitation pitting is given and the setting of the machine is
agreed upon (see Figure 1b).
In most cases, a machine can be operated normally without cavitation pitting or may be
required to operate without cavitation pitting. In some cases, it may be more economical to
accept a slight amount of cavitation pitting, which means using a higher setting than would be
required for operation of the machine without cavitation pitting. Of course, in the case of
underground power stations, the cost of additional submergence is usually relatively low.
It is not feasible to make general recommendations for an acceptable amount of cavitation
pitting primarily because items a) through e) make each plant unique. Economic evaluations,
therefore, are recommended for each case as conditions warrant. For example, a deeper
setting of the machine (higher σ value for the plant requiring higher cost for civil work) and/or a
more expensive runner/impeller (shape and/or material) can reduce the amount of cavitation
pitting. The benefits of these higher purchase costs are a reduction in the operating cost and/or
frequency of repair, as well as a reduction in lost energy production during the shut-down of the
unit.
Examples of amounts of cavitation pitting expressed as depth and volume (see 2.2.26 and
2.2.27) as a function of runner/impeller diameter D are given in Annex A.

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 11 –
σ plant given by contract document

Agreed upon cavitation pitting
σ
IEC  1482/04
Figure 1a
Agreed upon σ plant
Permissible amount established
by contract document
σ
IEC  1483/04
Figure 1b
Figure 1 – Amount of cavitation pitting as a function of σσσσ
for a given machine at constant discharge
Amount of cavitation pitting
Amount of cavitation pitting

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 13 –
HYDRAULIC TURBINES, STORAGE PUMPS AND PUMP-TURBINES –
CAVITATION PITTING EVALUATION –
Part 1: Evaluation in reaction turbines, storage pumps
and pump-turbines
1 Scope and object
This part of IEC 60609 serves as a basis for the formulation of guarantees applied to cavitation
pitting for reaction hydraulic turbines, storage pumps and pump-turbines. It addresses the
measurement and evaluation of the amount of cavitation pitting on certain specified machine
components for given conditions, which are defined in the contract by output, specific hydraulic
energy (E), speed, material, operation, etc.
The cavitation-pitting evaluation is based on the loss of material during a given time and under
accurately defined operating conditions. All wetted surfaces are considered.
The contract documents shall state whether cavitation pitting on the hydraulic machine should
or should not be anticipated in all or in some operating ranges.
Guarantees that restrict the extent of cavitation pitting are necessary in the contract whether
cavitation pitting is anticipated or not.
1.1 Excluded topics and limitations
This standard does not cover other effects which cavitation may possibly have on the machine
such as:
– output, efficiency, vibration, mechanical integrity, and noise; and
– material defects revealed during operation.
Material defects revealed by wear on the machine surfaces during operation are not included in
a guarantee against cavitation pitting.
1.2 Considerations concerning chemical composition of water
It is assumed in this standard that the water is not chemically aggressive. In cases where the
water is considered to be chemically aggressive, the cavitation-pitting guarantee shall be given
on the basis of an agreed water analysis. Since chemical aggressiveness is dependent upon so
many possible chemical compositions, and the materials of the machine, it is beyond the scope
of this standard to set particular limits.
If it becomes apparent in the course of later analysis that the water is in fact more aggressive
than the agreed analysis indicated, this must be taken into consideration when evaluating
whether the cavitation-pitting guarantees have been met. If cavitation pitting occurs in zones
where damage can be separately attributable to chemical or electrochemical corrosion, such
damage shall be excluded from the evaluation of cavitation pitting. If cavitation pitting occurs in
zones where damage can be proven to have been increased by chemical or electrochemical
effects additional to those normal to cavitation in water of the agreed analysis, then such zones
shall be excluded from the evaluation of cavitation pitting.

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 15 –
1.3 Considerations concerning water containing solids
Abrasion due to water contaminated with solids (for example, sand) cannot be considered as
cavitation-pitting damage. When a machine operates in water containing a significant amount of
solids, the weight loss of material will be intensified due to the joint action of both cavitation
pitting (if it exists) and abrasion. The degree of intensifying destruction depends on various
aspects, such as sediment concentration, mineral composition, size gradation and impact
parameters (i.e. relative velocity and incidence angle) as well as the material characteristics
and hydraulic machine operation conditions. When a surface is altered by abrasion erosion,
cavitation-pitting damage can be initiated and accelerated because of the hydraulic shape
change. With respect to measurement of damage, it is important to realize that, for cavitation
erosion damage and abrasion erosion damage, the appearance, position and mechanism of
destruction is not similar. If cavitation pitting occurs in zones where damage can be separately
attributed to abrasion, such damage shall be excluded from the evaluation of cavitation pitting.
While the examples of amounts of cavitation pitting and measurement methods given in this
standard cover cavitation-pitting damage only, it must be recognized that some hydro sites
operate in water that contains significant amounts of solids for at least some portion of the
year. Since erosion due to abrasion is so dependent on the above-mentioned parameters, it is
beyond the scope of this standard to define an acceptable amount of solids content.
The contract documents shall describe the solids content of the water and, if relevant, the types
of minerals and size of solid (sand) particles in the water analysis and, if it reaches significant
proportion, shall be the subject of a special agreement. This agreement could consider the
volume loss caused by cavitation pitting and abrasion erosion separately. However, in practice
it is extremely difficult to measure them separately. It may be preferable that the contractor
guarantee the material loss as a combination of cavitation pitting and abrasion. Aspects of
abrasion wear by sand erosion are dealt with in IEC 61366-1.
1.4 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 60193, Hydraulic turbines, storage pumps and pump-turbines – Model acceptance tests
IEC TR 61366-1, Hydraulic turbines, storage pumps and pump-turbines – Tendering documents
– Part 1: General and annexes
2 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
2.1 Units
The International System of Units (SI) is adopted throughout this standard but other systems
are allowed.

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 17 –
2.2 Terms and definitions
The terms, symbols and definitions adopted in this standard are listed below.
NOTE They are also based, where relevant, on IEC 61364.
cavitation vapour bubbles which form when the level of local pressure
2.2.1
drops to approximately that of vapour pressure and which
collapse when the level of local pressure rises above that of
vapour pressure
2.2.2 cavitation pitting loss of material caused by cavitation
2.2.3 cavitation factor (Thoma number) characterizing the setting of a
σ
hydraulic machine referred to the tailwater level or suction
water level (see IEC 60193)
2.2.4 cavitation pitting number of months or years of service of a machine during
guarantee period which the cavitation pitting guarantee is valid
2.2.5 cavitation pitting number of machine operating hours during which the cavitation
guarantee pitting guarantee is valid
duration of
operation
2.2.6 reference duration number of machine operating hours used as a reference value
of operation t (h) for establishing cavitation-pitting guarantees
R
2.2.7 actual duration of the actual number of machine operating hours at the time of
operation t (h) cavitation-pitting examination
A
P
2.2.8 lower limit of turbine power for continuous operation specified
CL
for each specific hydraulic energy and each permissible NPSE
(see Figure 2)
2.2.9 P upper limit of turbine power for continuous operation specified
CU
for each specific hydraulic energy and each permissible NPSE
(see Figure 2)
P
2.2.10 lower limit of turbine power for temporary operation specified
TL
for each specific hydraulic energy and each permissible NPSE
(see Figure 2)
2.2.11 P upper limit of turbine power for temporary operation specified
TU
for each specific hydraulic energy and each permissible NPSE
(see Figure 2)
–1
2.2.12 E(Jkg ) specific hydraulic energy of machine, E = gH (see 2.2.14 and
for full information, see IEC 60193)
–2
2.2.13 g (ms ) acceleration due to gravity for the considered plant (for full
information, see IEC 60193)
2.2.14 H (m) head of machine H = E/g
–1
2.2.15 NPSE(Jkg ) net positive suction specific energy in operation (for full
information, see IEC 60193)
2.2.16 E lower limit of specific hydraulic energy for normal continuous
CL
operation specified for each permissible NPSE (Figures 2 and 3)

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SIST EN 60609-1:2005
60609-1 ” IEC:2004 – 19 –
2.2.17 E upper limit of specific hydraulic energy for normal continuous
CU
operation specified for each permissible NPSE (Figures 2 and
3)
2.2.18 E lower limit of specific hydraulic energy for temporary abnormal
TL
operation specified for each permissible NPSE (Figures 2 and
3). In many applications, E can be the same as E
TL CL
2.2.19 E upper limit of specific hydraulic energy for temporary
TU
abnormal operation specified for each permissible NPSE
(Figures 2 and 3). In many applications, E can be the same
TU
as E
CU
2.2.20 NPSE lowest permissible value of NPSE (see 2.2.15)
L
2.2.21 normal continuous Limited a) for turbine mode by P , P , E and E
CL CU, CL CU
operating range (Figure 2) and b) for pumps and pump cycle of pump-turbines
by E and E (Figure 3)
CL CU
2.2.22 high-load Limited by P and P (Figure 2)
CU TU
temporary
operating range in
turbine mode
2.2.23 low-load Limited by P and P (Figure 2)
CL TL
temporary
operating range in
turbine mode
2.2.24 low specific Limited by E and E (Figure 2 or 3)
CL TL
hydraulic energy
temporary
operating range
2.2.25 high specific Limited by E and E (Figure 2 or 3)
CU TU
hydraulic energy
temporary
operating range
2.2.26.1 S (mm) absolute maximum depth of any pitted area measured from
the original surface (see 4.2.1)
2.2.26.2 S , S , S ,…S maximum depth of a particular pitted area measured from the
1 2 3 i
original surface (see 4.2.2 and 4.2.3b)
(mm)
3
2.2.27 V (cm ) volume of material removed by cavitation pitting
2.2.28 A , A , A ,…A individual areas damaged by cavitation pitting (see 4.2.2 and
1 2 3 i
2
(cm ) 4.2.3b)
2.2.29 K k , k , k ,…k coefficients used in the approximate calculation of volume as
1 2 3 i
indicated in 4.2.3b
3
2.2.30 C (mm, cm ) guaranteed limit of the amount of cavitation pitting for the
R
reference duration of operation
3
2.2.31 C (mm, cm ) guaranteed limit of the amount of cavitation pitting at the time
A
of cavitation-pitting examination

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SIST EN 60609-1:2005
60609-1 © IEC:2004 – 21 –
2.2.32 D (m) in the case of Kaplan and propeller turbines, runner blade tip
diameter at exit
in the case of Francis turbines, the outlet diameter of the
runner
in the case of storage pumps and pump-turbines during
pumping operation, the inlet diameter of the impeller (for any
other type of machine, see IEC 60193)
mass of
...