EN 60034-18-1:1994/A1:1996

SLOVENSKI STANDARD
01-april-1999
Rotating electrical machines - Part 18: Functional evaluation of insulation systems
- Section 1: General guidelines (IEC 60034-18-1:1992/A1:1996)
Rotating electrical machines -- Part 18: Functional evaluation of insulation systems --
Section 1: General guidelines
Drehende elektrische Maschinen -- Teil 18: Funktionelle Bewertung von Isoliersystemen
-- Hauptabschnitt 1: Allgemeine Richtlinien
Machines électriques tournantes -- Partie 18: Evaluation fonctionnelle des systèmes
d'isolation -- Section 1: Principes directeurs généraux
Ta slovenski standard je istoveten z: EN 60034-18-1:1994/A1:1996
ICS:
29.080.30 Izolacijski sistemi Insulation systems
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.

NORME
CEI
INTERNATIONALE
IEC
34-18-1
INTERNATIONAL
STANDARD
AMENDEMENT 1
AMENDMENT 1
1996-11
Amendement 1
Machines électriques tournantes –
Partie 18:
Evaluation fonctionnelle des systèmes d'isolation –
Section 1: Principes directeurs généraux
Amendment 1
Rotating electrical machines –
Part 18:
Functional evaluation of insulation systems –
Section 1: General guidelines
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34-18-1 Amend. 1  IEC:1996 – 3 –
FOREWORD
This amendment has been prepared by sub-committee 2J: Classification of insulation systems
for rotating machinery, of IEC technical committee 2: Rotating machinery.
The text of this amendment is based on the following documents:
FDIS Report on voting
2J/53/FDIS 2J/60/RVD
Full information on the voting for the approval of this amendment can be found in the report on
voting indicated in the above table.
__________
Page 7
INTRODUCTION
Replace the text in the fourth paragraph by the following:
IEC 85 deals with thermal evaluation of insulating materials and insulation systems used in
electrical equipment. In particular, the thermal classes of insulation systems used in rotating
machines such as A, E, B, F and H, as well as the temperatures usually associated with these
thermal classes, are established in IEC 85. In the past, materials for insulation systems were
often selected solely on the basis of thermal endurance of individual materials. However, the
second edition of IEC 85 recognizes that such selection may be used only for screening
materials prior to further functional evaluation of a new insulation system which is not service-
proven. This evaluation is linked with earlier service experience through the use of a service-
proven reference insulation system as the basis for comparative evaluation. Service
experience is the preferred basis for assessing the thermal endurance of an insulation system.
Replace the text in the ninth and tenth paragraphs by the following:
In the winding of an electrical machine, different factors of influence can be dominant in
different parts (e.g. turn insulation and end winding insulation). Therefore, different criteria may
be used to assess those parts of the insulation. It can also be appropriate to apply different
procedures of functional evaluation to these parts.
The large differences found in the rotating electrical machine windings, in terms of size, voltage
and operating conditions, necessitate the use of different procedures of functional evaluation to
evaluate various types of windings. These procedures can also be of different complexity, the
simplest being based on a single ageing mechanism (e.g. thermal or electrical). In the present
state of the art, only thermal and electrical endurance testing procedures can be specified in
some detail. Principles of mechanical, environmental and multifactor functional testing are
briefly described to provide a basis for provisions to be developed later where appropriate.

34-18-1 Amend. 1  IEC:1996 – 5 –
Page 11
3  Definitions
Replace, on page 13, subclause 3.2.2 by the following:
3.2.2 test specimen: An individual component within a test object which can be used to
generate one piece of test data (e.g. time to failure). A test specimen may contain more than
one insulation component (e.g. turn insulation and conductor to earth insulation), any one of
which can provide that piece of data.
Replace subclause 3.3.1 by the following:
3.3.1 factor of influence: A stress or environmental influence which can affect the
performance of insulation in the machine during service.
Replace subclause 3.3.2 by the following:
3.3.2 ageing factor: A factor of influence which can produce ageing.
Replace, on page 15, subclause 3.4.2 by the following:
3.4.2 functional test: A test in which the insulation system of a test object is exposed to
ageing factors simulating service conditions, in order to obtain information about serviceability,
including evaluation of test results.
4.1  Effects of ageing factors
Replace, on page 17, the existing text of the third and fourth paragraphs by the following:
Medium to large machines, using form-wound windings, also are affected by temperature and
environment but in addition the electrical and mechanical stresses can also be important
ageing factors.
Very large machines, which usually utilize bar-type windings and which can operate in an inert
environment such as hydrogen, are normally most affected by mechanical stresses or electrical
stresses or both. Temperature and environment can be less significant ageing factors.
4.3  Functional tests
Replace the existing text of the second paragraph by the following:
Generally, the functional tests are performed in cycles, each cycle consisting of an ageing sub-
cycle and a diagnostic sub-cycle. In the ageing sub-cycle, the test specimens are exposed to
the specified ageing factor, intensified appropriately to accelerate ageing. In the diagnostic
sub-cycle, the test specimens are subjected to appropriate diagnostic tests to determine the
end of test life or to measure relevant properties of the insulation system at that time. In some
cases, the ageing factor itself can act as the diagnostic factor and produce the end-point.

34-18-1 Amend. 1  IEC:1996 – 7 –
Page 19
5.1  General aspects of thermal functional tests
Replace the existing text of the fifth paragraph by the following:
The thermal ageing processes in rotating electrical machines can be complex in nature. Since
also the insulation systems of rotating machines are generally complicated in varying degrees,
simple systems referred to in IEC 85 do not exist in rotating machines.
5.1.1  Reference insulation system
Replace the existing text of the second paragraph by the following:
All test procedures shall be equivalent, allowing for the fact that when the design values of the
two systems are different, then appropriate differences in temperatures, ageing sub-cycle
lengths and diagnostic tests may be used, when technically justified (see table 2).
5.2.1  Construction of test objects
Replace the existing texts of the first two paragraphs by the following:
It is expected that the various insulating materials or components making up any insulation
system to be evaluated by these test procedures will first be screened properly. Temperature
indices for insulating materials may be obtained by following the procedures outlined in
IEC 216. However, temperature indices of insulating materials may not be used to classify
insulation systems but are to be considered only as indicators for the thermal functional tests
for systems.
Wherever economics or the size of the machine, or both, warrant it, an actual machine or
machine component should be used as the test object. Usually this means that coils of full
cross-section, with actual clearances and creepage distances are needed, though a reduced
slot length may be used.
Page 21
5.3.1 General principles
This correction applies to the French text only.

34-18-1 Amend. 1  IEC:1996 – 9 –
Replace, on page 23, the text of the fourth and fifth paragraphs by the following:
In other cases, mechanical stress, moisture exposure and application of voltage are possibly
not the best diagnostic tests. It is appropriate to replace them by selected dielectric tests (e.g.,
measurement of partial discharge or loss tangent) to check the condition of the insulation after
each thermal ageing sub-cycle.
It should be realized that greater mechanical stress and higher concentration of the products of
decomposition can occur during ageing tests at higher than normal temperature. Also, it is
recognized that failures from abnormally high mechanical stress or voltage are generally of a
different character from those failures which are produced in long service.
Replace the text of the sixth paragraph by the following:
If it is necessary to verify results in another laboratory it can be found that the actual numerical
test-life values differ unle
...