# EN 60216-3:2006

(Main)## Electrical insulating materials - Thermal endurance properties - Part 3: Instructions for calculating thermal endurance characteristics

## Electrical insulating materials - Thermal endurance properties - Part 3: Instructions for calculating thermal endurance characteristics

IEC 60216-3:2006 specifies the calculation procedures to be used for deriving thermal endurance characteristics from experimental data obtained in accordance with the instructions of IEC 60216-1 and IEC 60216-2, using fixed ageing temperatures and variable ageing times. The experimental data may be obtained using non-destructive, destructive or proof tests. Data obtained from non-destructive or proof tests may be incomplete, in that measurement of times taken to reach the endpoint may have been terminated at some point after the median time but before all specimens have reached end-point. The procedures are illustrated by worked examples, and suitable computer programs are recommended to facilitate the calculations. The major technical changes with regard to the first edition concern an updating of Table C.2. In addition, the scope has been extended to cover a greater range of data characteristics, particularly with regard to incomplete data, as often obtained from proof test criteria. The greater flexibility of use should lead to more efficient employment of the time available for ageing purposes. Finally, the procedures specified in this part of IEC 60216 have been extensively tested and have been used to calculate results from a large body of experimental data obtained in accordance with other parts of the standard. Annex E "Computer program" has been completely reworked.

## Elektroisolierstoffe - Eigenschaften hinsichtlich des thermischen Langzeitverhaltens --Teil 3: Anweisungen zur Berechnung thermischer Langzeitkennwerte

## Matériaux isolants électriques - Propriétés d'endurance thermique - Partie 3: Instructions pour le calcul des caractéristiques d'endurance thermique

La CEI 60216-3:2006 spécifie les méthodes de calcul à utiliser pour obtenir les caractéristiques d'endurance thermique à partir des données expérimentales obtenues conformément aux instructions de la CEI 60216-1 et de la CEI 60216-2, en utilisant des températures de vieillissement fixes et des temps de vieillissement variables. Les données expérimentales peuvent être obtenues en utilisant des essais non destructifs, des essais destructifs et des essais d'épreuve. Les données obtenues à partir d'essais non destructifs ou d'essais d'épreuve peuvent être incomplètes, car la mesure des temps mis pour atteindre le point limite peut avoir été arrêtée à un moment situé après le temps médian, mais avant que toutes les éprouvettes n'aient atteint le point limite. Les méthodes sont illustrées par des exemples pratiques, et des programmes informatiques adaptés sont recommandés pour faciliter les calculs. Les modifications majeures par rapport à la première édition concernent la mise à jour du Tableau C.2. De plus, le domaine d'application a été élargi pour couvrir une plus grande gamme de caractéristiques de données, en particulier en ce qui concerne les données incomplètes, comme cela est souvent le cas pour les données obtenues à partir de critères d'essai d'épreuve. Il convient que cette plus grande souplesse d'utilisation conduise à un emploi plus efficace du temps disponible pour les essais de vieillissement. Enfin, les méthodes spécifiées dans cette partie de la CEI 60216 ont été largement soumises aux essais et ont été utilisées pour calculer les résultats à partir d'un grand nombre de données expérimentales obtenues conformément aux autres parties de la norme. L'Annexe E "Programme informatique" a été complètement remaniée.

## Električni izolacijski materiali - Lastnosti v zvezi s toplotno vzdržljivostjo - 3. del: Navodila za izračunavanje karakteristik toplotne vzdržljivosti (IEC 60216-3:2006)

### General Information

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### Standards Content (Sample)

SLOVENSKI SIST EN 60216-3:2006

STANDARD

oct 2006

Električni izolacijski materiali – Lastnosti v zvezi s toplotno vzdržljivostjo – 3.

del: Navodila za izračunavanje karakteristik toplotne vzdržljivosti (IEC 60216-3:2006)

Electrical insulating materials - Thermal endurance properties – Part 3: Instructions

for calculating thermal endurance characteristics (IEC 60216-3:2006)ICS 29.035.01 Referenčna številka

SIST EN 60216-3:2006(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------EUROPEAN STANDARD

EN 60216-3

NORME EUROPÉENNE

July 2006

EUROPÄISCHE NORM

ICS 17.220.99; 19.020; 29.035.01 Supersedes EN 60216-3:2002

English version

Electrical insulating materials -

Thermal endurance properties

Part 3: Instructions for calculating thermal endurance characteristics

(IEC 60216-3:2006)

Matériaux isolants électriques - Elektroisolierstoffe –

Propriétés d'endurance thermique Eigenschaften hinsichtlich des

Partie 3: Instructions pour le calcul des thermischen Langzeitverhaltens

caractéristiques d'endurance thermique Teil 3: Anweisungen zur Berechnung

(CEI 60216-3:2006) thermischer Langzeitkennwerte

(IEC 60216-3:2006)

This European Standard was approved by CENELEC on 2006-06-01. 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, 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

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60216-3:2006 E---------------------- Page: 2 ----------------------

EN 60216-3:2006 - 2 -

Foreword

The text of document 112/26/FDIS, future edition 2 of IEC 60216-3, prepared by IEC TC 112, Evaluation

and qualification of electrical insulating materials and systems, was submitted to the IEC-CENELEC

parallel vote and was approved by CENELEC as EN 60216-3 on 2006-06-01.This European Standard supersedes EN 60216-3:2002.

The major technical changes with regard to EN 60216-3:2002 concern an updating of Table C.2. In

addition, the scope has been extended to cover a greater range of data characteristics, particularly with

regard to incomplete data, as often obtained from proof test criteria. The greater flexibility of use should

lead to more efficient employment of the time available for ageing purposes. Finally, the procedures

specified in this part of EN 60216 have been extensively tested and have been used to calculate results

from a large body of experimental data obtained in accordance with other parts of the standard. Annex E

'Computer program' has been completely reworked.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) 2007-03-01

– latest date by which the national standards conflicting

with the EN have to be withdrawn (dow) 2009-06-01

Annex ZA has been added by CENELEC.

__________

Endorsement notice

The text of the International Standard IEC 60216-3:2006 was 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 60216-5 NOTE Harmonized as EN 60216-5:2003 (not modified).__________

---------------------- Page: 3 ----------------------

- 3 - EN 60216-3:2006

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 60216-1 2001 Electrical insulating materials - Properties of EN 60216-1 2001

thermal endurance

Part 1: Ageing procedures and evaluation of

test results

IEC 60216-2 2005 Electrical insulating materials - Thermal EN 60216-2 2005

endurance properties

Part 2: Determination of thermal endurance

properties of electrical insulating materials -

Choice of test criteria

IEC 60493-1 1974 Guide for the statistical analysis of ageing - -

test data

Part 1: Methods based on mean values of

normally distributed test results

---------------------- Page: 4 ----------------------

INTERNATIONAL IEC

STANDARD 60216-3

Second edition

2006-04

Electrical insulating materials –

Thermal endurance properties –

Part 3:

Instructions for calculating thermal

endurance characteristics

IEC 2006 Copyright - all rights reserved

No part of this publication may be reproduced or utilized in any form or by any means, electronic or

mechanical, including photocopying and microfilm, without permission in writing from the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

PRICE CODECommission Electrotechnique Internationale X

International Electrotechnical Commission

МеждународнаяЭлектротехническаяКомиссия

For price, see current catalogue

---------------------- Page: 5 ----------------------

– 2 – 60216-3 IEC:2006(E)

CONTENTS

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

1 Scope...............................................................................................................................6

2 Normative references .......................................................................................................6

3 Terms, definitions, symbols and abbreviated terms...........................................................6

4 Principles of calculations ................................................................................................10

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

4.2 Preliminary calculations.........................................................................................10

4.3 Variance calculations ............................................................................................11

4.4 Statistical tests......................................................................................................12

4.5 Results..................................................................................................................12

5 Requirements and recommendations for valid calculations .............................................13

5.1 Requirements for experimental data ......................................................................13

5.2 Precision of calculations........................................................................................13

6 Calculation procedures...................................................................................................13

6.1 Preliminary calculations.........................................................................................13

6.2 Main calculations...................................................................................................17

6.3 Statistical tests......................................................................................................19

6.4 Thermal endurance graph .....................................................................................21

7 Calculation and requirements for results.........................................................................21

7.1 Calculation of thermal endurance characteristics...................................................21

7.2 Summary of statistical tests and reporting .............................................................22

7.3 Reporting of results ...............................................................................................22

8 Test report......................................................................................................................22

Annex A (normative) Decision flow chart.............................................................................24

Annex B (normative) Decision table ....................................................................................25

Annex C (informative) Statistical tables...............................................................................26

Annex D (informative) Worked examples ............................................................................35

Annex E (informative) Computer program ...........................................................................42

Bibliography..........................................................................................................................50

Figure D.1 – Thermal endurance graph.................................................................................39

Figure D.2 – Example 3: Property-time graph (destructive test data).....................................41

Table B.1 – Decisions and actions according to tests............................................................25

Table C.1 – Coefficients for censored data calculations ........................................................26

Table C.2 – Fractiles of the F-distribution, F(0,95 ,f ,f ).........................................................32

n dTable C.3 – Fractiles of the F-distribution, F(0,995 ,f ,f ) ........................................................33

n dTable C.4 –Fractiles of the t-distribution, t ......................................................................34

0,95Table C.5 – Fractiles of the χ -distribution............................................................................34

---------------------- Page: 6 ----------------------60216-3 IEC:2006(E) – 3 –

Table D.1 – Worked example 1 – Censored data (proof tests)...............................................35

Table D.2 – Worked example 2 – Complete data (non-destructive tests) ...............................37

Table D.3 – Worked example 3 – Destructive tests ...............................................................40

Table E.1 – Non-destructive test data ...................................................................................43

Table E.2 – Destructive test data ..........................................................................................44

---------------------- Page: 7 ----------------------– 4 – 60216-3 IEC:2006(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________

ELECTRICAL INSULATING MATERIALS –

THERMAL ENDURANCE PROPERTIES –

Part 3: Instructions for calculating thermal

endurance characteristics

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 60216-3 has been prepared by IEC technical committee 112:

Evaluation and qualification of electrical insulating materials and systems .This second edition of IEC 60216-3 cancels and replaces the first edition, published in 2002,

and constitutes a technical revision.The major technical changes with regard to the first edition concern an updating of Table C.2.

In addition, the scope has been extended to cover a greater range of data characteristics,

particularly with regard to incomplete data, as often obtained from proof test criteria. The

greater flexibility of use should lead to more efficient employment of the time available for

ageing purposes. Finally, the procedures specified in this part of IEC 60216 have been

extensively tested and have been used to calculate results from a large body of experimental

data obtained in accordance with other parts of the standard. Annex E “Computer program”

has been completely reworked.—————————

Provisional title: IEC technical committee 112 has been formed out of a merger between subcommittee 15E and

technical committee 98.---------------------- Page: 8 ----------------------

60216-3 IEC:2006(E) – 5 –

The text of this standard is based on the following documents:

FDIS Report on voting

112/26/FDIS 112/29/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 60216 consists of the following parts, under the general title Electrical insulating

materials – Thermal endurance properties :Part 1: Ageing procedures and evaluation of test results

Part 2: Determination of thermal endurance properties of electrical insulating materials –

Choice of test criteriaPart 3: Instructions for calculating thermal endurance characteristics

Part 4: Ageing ovens

Part 5: Determination of relative thermal endurance index (RTE) of an insulating material

Part 6: Determination of thermal endurance indices (TI and RTE) of an insulating material

using the fixed time frame methodNOTE This series may be extended. For revisions and new parts, see the current catalogue of IEC publications

for an up-to-date list.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.

A CD-ROM containing the computer program and data files referred to in Annex E is affixed to

the back cover of this publication.A bilingual version of this publication may be issued at a later date.

—————————

Titles of existing parts in this series will be updated at the time of their next revision.

---------------------- Page: 9 ----------------------– 6 – 60216-3 IEC:2006(E)

ELECTRICAL INSULATING MATERIALS –

THERMAL ENDURANCE PROPERTIES –

Part 3: Instructions for calculating thermal

endurance characteristics

1 Scope

This part of IEC 60216 specifies the calculation procedures to be used for deriving thermal

endurance characteristics from experimental data obtained in accordance with the instructions

of IEC 60216-1 and IEC 60216-2, using fixed ageing temperatures and variable ageing times.

The experimental data may be obtained using non-destructive, destructive or proof tests. Data

obtained from non-destructive or proof tests may be incomplete, in that measurement of times

taken to reach the endpoint may have been terminated at some point after the median time

but before all specimens have reached end-point.The procedures are illustrated by worked examples, and suitable computer programs are

recommended to facilitate the calculations.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 60216-1:2001, Electrical insulating materials – Properties of thermal endurance – Part 1:

Ageing procedures and evaluation of test resultsIEC 60216-2:2005, Electrical insulating materials – Properties of thermal endurance – Part 2:

Determination of thermal endurance properties of electrical insulating materials – Choice of

test criteriaIEC 60493-1:1974, Guide for the statistical analysis of ageing test data – Part 1: Methods

based on mean values of normally distributed test results3 Terms, definitions, symbols and abbreviated terms

3.1 Terms and definitions

For the purposes of this document, the following definitions apply.

3.1.1

ordered data

group of data arranged in sequence so that in the appropriate direction through the sequence

each member is greater than, or equal to, its predecessorNOTE 1 In this standard, ascending order implies that the data is ordered in this way, the first being the smallest.

NOTE 2 It has been established that the term “group” is used in the theoretical statistics literature to represent a

subset of the whole data set. The group comprises those data having the same value of one of the parameters of

the set (e.g. ageing temperature). A group may itself comprise a number of sub-groups characterised by another

parameter (e.g. time in the case of destructive tests).---------------------- Page: 10 ----------------------

60216-3 IEC:2006(E) – 7 –

3.1.2

order-statistic

each individual value in a group of ordered data is referred to as an order-statistic identified

by its numerical position in the sequence3.1.3

incomplete data

ordered data, where the values above and/or below defined points are not known

3.1.4

censored data

incomplete data, where the number of unknown values is known.

NOTE 1 If the censoring is begun above/below a specified numerical value, the censoring is Type I.

If above/below a specified order-statistic it is Type II This standard is concerned only with Type II.

3.1.5degrees of freedom

number of data values minus the number of parameter values

3.1.6

variance of a data group

sum of the squares of the deviations of the data from a reference level.

NOTE 1 The reference level may be defined by one or more parameters, for example a mean value (one

parameter) or a line (two parameters, slope and intercept), divided by the number of degrees of freedom

3.1.7central second moment of a data group

sum of the squares of the differences between the data values and the value of the group

mean, divided by the number of data in the group3.1.8

covariance of data groups

for two groups of data with equal numbers of elements where each element in one group

corresponds to one in the other, the sum of the products of the deviations of the

corresponding members from their group means, divided by the number of degrees of

freedom3.1.9

regression analysis

process of deducing the best-fit line expressing the relation of corresponding members of two

data groups by minimizing the sum of squares of deviations of members of one of the groups

from the lineNOTE The parameters are referred to as the regression coefficients.

3.1.10

correlation coefficient

number expressing the completeness of the relation between members of two data groups,

equal to the covariance divided by the square root of the product of the variances of the

groupsNOTE The value of its square is between 0 (no correlation) and 1 (complete correlation).

3.1.11end-point line

line parallel to the time axis intercepting the property axis at the end-point value

---------------------- Page: 11 ----------------------– 8 – 60216-3 IEC:2006(E)

3.2 Symbols and abbreviated terms

Subclause

a Regression coefficient (y-intercept) 4.3, 6.2

a Regression coefficient for destructive test calculations 6.1

b Regression coefficient (slope) 4.3, 6.2

b Regression coefficient for destructive test calculations 6.1

b Intermediate constant (calculation of X) 6.3

c Intermediate constant (calculation of χ) 6.3

f Number of degrees of freedom Tables C.2 to C5

F Fisher distributed stochastic variable 4.2, 6.1, 6.3

F Tabulated value of F (linearity of thermal endurance graph) 4.4, 6.3

F Tabulated value of F (linearity of property graph – significance 0,05) 6.1

F Tabulated value of F (linearity of property graph – significance 0,005) 6.1

g Order number of ageing time for destructive tests 6.1

h Order number of property value for destructive tests 6.1

HIC Halving interval at temperature equal to TI 4.3, 7

HIC Halving interval corresponding to TI 7.3

g g

i Order number of exposure temperature 4.1, 6.2

j Order number of time to end-point 4.1, 6.2

k Number of ageing temperatures 4.1, 6.2

m Number of specimens aged at temperature ϑ 4.1, 6.1

i i

N Total number of times to end-point 6.2

n Number of property values in group aged for time τ 6.1

g g

n Number of values of y at temperature ϑ 4.1, 6.1

i i

p Mean value of property values in selected groups 6.1

p Value of diagnostic property 6.1

P Significance level of χ distribution 4.4, 6.3.1

p Value of diagnostic property at end-point for destructive tests 6.1

p Mean of property values in group aged for time τ 6.1

g g

p Individual property value 6.1

q Base of logarithms 6.3

r Number of ageing times selected for inclusion in calculation

(destructive tests) 6.1

r Square of correlation coefficient 6.2.3

2 2

s Weighted mean of s and s 6.3

1 2

2 2

s Weighted mean of s , pooled variance within selected groups 4.3, 6.1 - 6.3

2 2

(s ) Adjusted value of s 4.4, 6.3

a 1

s Variance of property values in group aged for time τ 6.1

s Variance of y values at temperature ϑ 4.3, 6.2

ij i

s Variance about regression line 6.1 - 6.3

s Adjusted value of s 6.3

---------------------- Page: 12 ----------------------

60216-3 IEC:2006(E) – 9 –

s Intermediate constant 6.3

Variance of Y 6.3

t Student distributed stochastic variable 6.3

t Adjusted value of t (incomplete data) 6.3

TC Lower 95 % confidence limit of TI 4.4, 7

TC Adjusted value of TC 7.1

TI Temperature Index 4.3, 7

TI Temperature Index at 10 kh 7.1

TI Adjusted value of TI 7.3

TI Temperature index obtained by graphical means or

without defined confidence limits 7.3

x Independent variable: reciprocal of thermodynamic temperature

x Weighted mean value of x 6.2

X Specified value of x for estimation of y 6.3

X Estimated value of x at specified value of y 6.3

ˆ ˆ

X Upper 95 % confidence limit of X 6.3

x Reciprocal of thermodynamic temperature corresponding to ϑ 4.1, 6.1

i i

y Weighted mean value of y 6.2

y Dependent variable: logarithm of time to end-point

Y Estimated value of y at specified value of x 6.3

Y Specified value of y for estimation of x 6.3

ˆ ˆ

Y Lower 95 % confidence limit of Y 6.3

y Mean values of y at temperature ϑ 4.3, 6.2

i ij i

y Value of y corresponding to τ 4.1, 6.1

ij ij

z Mean value of z 6.1

z Logarithm of ageing time for destructive tests – group g 6.1

α Censored data coefficient for variance 4.3, 6.2

β Censored data coefficient for variance 4.3, 6.2

ε Censored data coefficient for variance of mean 4.3, 6.2

Θ The temperature 0 °C on the thermodynamic scale (273,15 K) 4.1, 6.1

ϑ Estimate of temperature for temperature index 6.3.3

ˆ ˆ

ϑ Confidence limit of ϑ 6.3.3

ϑ Ageing temperature for group i 4.1, 6.1

µ Censored data coefficient for mean 4.3, 6.2

µ (x) Central second moment of x values 6.2, 6.3

ν Total number of property values selected at one ageing temperature 6.1

τ Time selected for estimate of temperature 6.3

τ Times to end-point 6.4

2 2

χ χ -distributed stochastic variable 6.3

---------------------- Page: 13 ----------------------

– 10 – 60216-3 IEC:2006(E)

4 Principles of calculations

4.1 General principles

The general calculation procedures and instructions given in Clause 6 are based on the principles

set out in IEC 60493-1. These may be simplified as follows (see 3.7.1 of IEC 60493-1:1974):

a) the relation between the mean of the logarithms of the times taken to reach the specified

end-point (times to end-point) and the reciprocal of the thermodynamic (absolute)

temperature is linear;b) the values of the deviations of the logarithms of the times to end-point from the linear

relation are normally distributed with a variance which is independent of the ageing

temperature.The data used in the general calculation procedures are obtained from the experimental data

by a preliminary calculation. The details of this calculation are dependent on the character of

the diagnostic test: non-destructive, proof or destructive (see 4.2). In all cases the data

comprise values of x, y, m, n and kwhere

x = 1/(ϑ + Θ ) is the reciprocal of thermodynamic value of ageing temperature ϑ in °C;

i i 0 iy = log τ is the logarithm of value of time (j) to end-point at temperature ϑ ;

ij ij i

n is the number of y values in group number i aged at temperature ϑ ;

i i

m is the number of samples in group number i aged at temperature ϑ (different from n for

i i icensored data);

k is the number of ageing temperatures or groups of y values.

NOTE Any number may be used as the base for logarithms, provided consistency is observed throughout

calculations. The use of natural logarithms (base e) is recommended, since most computer programming

languages and scientific calculators have this facility.4.2 Preliminary calculations

In all cases, the reciprocals of the thermodynamic values of the ageing temperatures are

calculated as the values of x .The values of y are calculated as the values of the logarithms of the individual times to end-

point τ obtained as described below.In many cases of non-destructive and proof tests, it is advisable for economic reasons, (for

example, when the scatter of the data is high) to stop ageing before all specimens have

reached the end-point, at least for some temperature groups. In such cases, the procedure for

calculation on censored data (see 6.2.1.2) shall be carried out on the (x, y) data available.

Groups of complete and incomplete data or groups censored at a different point for each

ageing temperature may be used together in one calculation in 6.2.1.2.4.2.1 Non-des

**...**

112/2/CDV

COMMITTEE DRAFT FOR VOTE (CDV)

PROJET DE COMITÉ POUR VOTE (CDV)

Project number IEC 60216-3, Ed.2 *

Numéro de projet

IEC/TC or SC: Date of circulation Closing date for voting (Voting

TC 112

Date de diffusion mandatory for P-members)

CEI/CE ou SC:

Date de clôture du vote (Vote

2005-07-01

obligatoire pour les membres (P))

2005-12-02 **

TC/SC Title: EVALUATION AND QUALIFICATION OF

Titre du CE/SC:

ELECTRICAL INSULATING MATERIALS AND

SYSTEMS (Provisional)

Secretary: Mr. Bernd Klaus Göttert

Secrétaire: E-mail: bernd_klaus.goettert@siemens.com

Also of interest to the following committees Supersedes document

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CONNAISSANCE ET À FOURNIR UNE DOCUMENTATION EXPLICATIVE. DOCUMENTATION.Titre : CEI 60216-3, Ed. 2: Matériaux isolants Title : IEC 60216-3, Ed. 2: Electrical insulating

électriques - Propriétés d'endurance thermique - materials - Thermal endurance properties - Part

Partie 3: Instructions pour le calcul des 3: Instructions for calculating thermal endurance

caractéristiques d'endurance thermique characteristicsNote d'introduction Introductory note

The French version of this CDV will be

distributed when available.

* IEC Central Office note: Document 15E/245/MCR indicated that this publication would be

amended. As the CDV has been presented as a revision, the maintenance project will

continue with eventual publication of Ed. 2.0. The major changes from the previous edition

relate to Table C2.** P-Members are requested to submit their comments no later than 2005-10-28, so that they

can be discussed at the next TC 112 meeting to be held at the beginning of November 2005.

ATTENTION ATTENTIONCDV soumis en parallèle au vote (CEI) Parallel IEC CDV/CENELEC Enquiry

et à l’enquête (CENELEC)

Copyright © 2005 International Electrotechnical Commission, IEC. All rights reserved. It is

permitted to download this electronic file, to make a copy and to print out the content for the sole

purpose of preparing National Committee positions. You may not copy or "mirror" the file or

printed version of the document, or any part of it, for any other purpose without permission in

writing from IEC.FORM CDV (IEC) 2002-08-09

---------------------- Page: 1 ----------------------

60216-3 Ed. 2/CDV © IEC – 2 –

CONTENTS

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

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

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

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

3 Terms, definitions, symbols and abbreviated terms..........................................................8

3.1 Terms and definitions ............................................................................................8

3.2 Symbols and abbreviated terms .............................................................................9

4 Principles of calculations ..............................................................................................11

4.1 General principles ...............................................................................................11

4.2 Preliminary calculations .......................................................................................12

4.2.1 Non-destructive tests ...............................................................................12

4.2.2 Proof tests ...............................................................................................12

4.2.3 Destructive tests ......................................................................................12

4.3 Variance calculations...........................................................................................13

4.4 Statistical tests ....................................................................................................13

4.5 Results................................................................................................................14

5 Requirements and recommendations for valid calculations ............................................15

5.1 Requirements for experimental data.....................................................................15

5.1.1 Non-destructive tests ...............................................................................15

5.1.2 Proof tests ...............................................................................................15

5.1.3 Destructive tests ......................................................................................15

5.2 Precision of calculations ......................................................................................15

6 Calculation procedures .................................................................................................16

6 Calculation procedures .................................................................................................16

6.1 Preliminary calculations .......................................................................................16

6.1.1 Temperatures and x-values ......................................................................16

6.1.2 Non-destructive tests ...............................................................................16

6.1.3 Proof tests ...............................................................................................16

6.1.4 Destructive tests ......................................................................................16

6.1.5 Incomplete data .......................................................................................19

6.2 Main calculations.................................................................................................19

6.2.1 Calculation of group means and variances................................................19

6.2.2 General means and variances ..................................................................20

6.2.3 Regression calculations ...........................................................................21

6.3 Statistical tests ....................................................................................................22

6.3.1 Variance equality test...............................................................................22

6.3.2 Linearity test (F-test)................................................................................22

6.3.3 Confidence limits of X and Y estimates .....................................................23

6.4 Thermal endurance graph ....................................................................................24

7 Calculation and requirements for results .......................................................................24

7.1 Calculation of thermal endurance characteristics ..................................................24

7.2 Summary of statistical tests and reporting ............................................................25

7.2 Summary of statistical tests and reporting ............................................................25

7.3 Reporting of results .............................................................................................25

8 Test report ...................................................................................................................25

---------------------- Page: 2 ----------------------60216-3 Ed. 2/CDV © IEC – 3 –

Annex A (normative) Decision flow chart ...........................................................................26

Annex A (normative) Decision flow chart ...........................................................................26

Annex B (normative) Decision table...................................................................................27

Annex B (normative) Decision table...................................................................................27

Annex C (informative) Statistical tables .............................................................................28

Annex C (informative) Statistical tables .............................................................................28

Annex D (informative) Worked examples ...........................................................................37

Annex D (informative) Worked examples ...........................................................................37

Annex E (informative) Computer programme .....................................................................44

Annex E (informative) Computer programme .....................................................................44

E.1 General ...............................................................................................................44

E.1.1 216-3.bas (or .exe) ..................................................................................44

E.1.2 Entry-3.bas (or .exe) ................................................................................44

E.2 Structure of data files used by the programme......................................................46

E.3 Data files for computer programme ......................................................................48

E.3 Data files for computer programme ......................................................................48

E.4 Output Files and Graph........................................................................................52

E.4 Output Files and Graph........................................................................................52

E.4.1 Thermal endurance Graph........................................................................52

E.4.2 Copying Graphs to Word Processor Reports .............................................52

---------------------- Page: 3 ----------------------60216-3 Ed. 2/CDV © IEC – 4 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________

ELECTRICAL INSULATING MATERIALS –

THERMAL ENDURANCE PROPERTIES –

Part 3: Instructions for calculating

thermal endurance characteristics

FOREWORD

1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.3) The documents produced have the form of recommendations for international use and are published in the form

of standards, technical specifications, technical reports or guides and they are accepted by the National

Committees in that sense.4) In order to promote international unification, IEC National Committees undertake to apply IEC International

Standards transparently to the maximum extent possible in their national and regional standards. Any

divergence between the IEC Standard and the corresponding national or regional standard shall be clearly

indicated in the latter.5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with one of its standards.6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject

of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60216-3 has been prepared by subcommittee 15E, Methods of

test, of IEC technical committee 15: Insulating materials.This version of the 1 edition published in 2002 has been revised, particularly regarding Table

C2. Some minor editorial amendments have been carried out.The text of this standard is based on the following documents:

FDIS Report on voting

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 3.

Future standards in this series will carry the new general title as cited above. Titles of existing

standards in this series will be updated at the time of the next revision.---------------------- Page: 4 ----------------------

60216-3 Ed. 2/CDV © IEC – 5 –

Annexes A and B form an integral part of this standard.

Annexes C, D and E are for information only.

The committee has decided that the contents of this publication will remain unchanged until 2006.

At this date, the publication will be• reconfirmed;

• withdrawn;

• replaced by a revised edition, or

• amended.

A diskette containing the computer programme and data files referred to in Annex E is affixed

to the back cover of this publication.---------------------- Page: 5 ----------------------

60216-3 Ed. 2/CDV © IEC – 6 –

INTRODUCTION

IEC 60216-3 series of publications was previously conceived as having four sections. Two of

these have been published, i.e. IEC 60216-3-1 and IEC 60216-3-2. The remaining two

sections were under consideration. Of these, section 4 is not now required, since the relative

thermal endurance index (RTE: then known as “Relative temperature index”) is now the

subject of Part 5. The second edition of this part of IEC 60216 combined the three remaining

sections into one standard, with substantial elimination of replicated matter. At the same time,

the scope was extended to cover a greater range of data characteristics, particularly with

regard to incomplete data, as often obtained from proof test criteria. The greater flexibility of

use should lead to more efficient employment of the time available for ageing purposes.

This part deals with thermal endurance determination using the conventional fixed

temperature procedure. Newly developed procedures using a fixed time ageing procedure are

the subject of Part 6.The procedures specified in this part of IEC 60216 have been extensively

tested and have been used to calculate results from a large body of experimental data

obtained in accordance with other parts of the standard.IEC 60216, which deals with the determination of thermal endurance properties of electrical

insulating materials, is composed of several parts:Part 1: Ageing procedures and evaluation of test results

Part 2: Choice of test criteria

Part 3: Instruction for calculating thermal endurance characteristics

Part 4-1: Ageing ovens – Single-chamber ovens

Part 4-2: Ageing ovens – Precision ovens for use up to 300 °C

Part 4-3: Ageing ovens – Multi-chamber ovens

Part 5: Determination of relative thermal endurance index (RTE) of an insulating material

Part 6: Determination of thermal endurance indices (TI and RTE) of an insulating material

using the fixed time frame methodNOTE This series may be extended. For revisions and new parts, see the current catalogue of IEC publications

for an up-to-date list.---------------------- Page: 6 ----------------------

60216-3 Ed. 2/CDV © IEC – 7 –

ELECTRICAL INSULATING MATERIALS –

THERMAL ENDURANCE PROPERTIES –

Part 3: Instructions for calculating

thermal endurance characteristics

1 Scope

This part of IEC 60216 specifies the calculation procedures to be used for deriving thermal

endurance characteristics from experimental data obtained in accordance with the instructions

of IEC 60216-1 and IEC 60216-2 using fixed ageing temperatures and variable ageing times.

The experimental data may be obtained using non-destructive, destructive or proof tests. Data

obtained from non-destructive or proof tests may be incomplete, in that measurement of times

taken to reach the endpoint may have been terminated at some point after the median time

but before all specimens have reached end-point.The procedures are illustrated by worked examples, and suitable computer programs are

recommended to facilitate the calculations.2 Normative references

The following normative documents contain provisions which, through reference in this text,

constitute provisions of this part of IEC 60216. For dated references, subsequent amend-

ments to, or revisions of, any of these publications do not apply. However, parties to

agreements based on this part of IEC 60216 are encouraged to investigate the possibility of

applying the most recent editions of the normative documents indicated below. For undated

references, the latest edition of the normative document referred to applies. Members of IEC

and ISO maintain registers of currently valid International Standards.IEC 60216-1:2001, Electrical insulating materials – Properties of thermal endurance – Part 1:

Ageing procedures and evaluation of test resultsIEC 60216-2:1990, Guide for the determination of thermal endurance properties of electrical

insulating materials – Part 2: Choice of test criteriaIEC 60493-1:1974, Guide for the statistical analysis of ageing test data – Part 1: Methods

based on mean values of normally distributed test results---------------------- Page: 7 ----------------------

60216-3 Ed. 2/CDV © IEC – 8 –

Terms, definitions, symbols and abbreviated terms

3.1 Terms and definitions

For the purposes of this part of IEC 60216, the following definitions apply:

3.1.1

ordered data

group of data arranged in sequence so that in the appropriate direction through the sequence

each member is greater than, or equal to, its predecessorNOTE 1 In this standard ascending order implies that the data is ordered in this way, the first being the smallest.

NOTE 2 It has been established that the term “group” is used in the theoretical statistics literature to

represent a subset of the whole data set, identified by having the same value of one parameter. It is

used both as noun and verb. The word "group" is used to mean “a number of objects (times,

temperatures, specimens etc) having one or more properties in common”.3.1.2

order-statistics

each individual value in a group of ordered data is referred to as an order-statistic identified

by its numerical position in the sequence3.1.3

incomplete data

ordered data, where the values above and/or below defined points are not known

3.1.4

censored data

incomplete data, where the number of unknown values is known. If the censoring is begun

above/below a specified numerical value, the censoring is Type I. If above/below a specified

order-statistic it is Type IINOTE 1 This standard is concerned only with Type II.

NOTE 2 The terminology employed in theoretical statistics literature is for Types I and II, not Types 1 and 2.

3.1.5degrees of freedom

number of data values minus the number of parameter values

3.1.6

variance of a data group

sum of the squares of the deviations of the data from a reference level defined by one or more

parameters, for example a mean value (one parameter) or a line (two parameters, slope and

intercept), divided by the number of degrees of freedom3.1.7

central second moment of a data group

sum of the squares of the differences between the data values and the value of the group

mean, divided by the number of data in the group3.1.8

covariance of data groups

for two groups of data with equal numbers of elements where each element in one group

corresponds to one in the other, the sum of the products of the deviations of the

corresponding members from their group means, divided by the number of degrees of

freedom---------------------- Page: 8 ----------------------

60216-3 Ed. 2/CDV © IEC – 9 –

3.1.9

regression analysis

process of deducing the best-fit line expressing the relation of corresponding members of two

data groups by minimizing the sum of squares of deviations of members of one of the groups

from the lineNOTE The parameters are referred to as the regression coefficients.

3.1.10

correlation coefficient

number expressing the completeness of the relation between members of two data groups,

equal to the covariance divided by the square root of the product of the variances of the

groupsNOTE The value of its square is between 0 (no correlation) and 1 (complete correlation).

3.1.11end-point line

line parallel to the time axis intercepting the property axis at the end-point value

3.2 Symbols and abbreviated termsClause

a Regression coefficient (y-intercept) 4.3, 6.2

a Regression coefficient for destructive test calculations 6.1

b Regression coefficient (slope) 4.3, 6.2

b Regression coefficient for destructive test calculations 6.1

b Intermediate constant (calculation of X) 6.3

c Intermediate constant (calculation of χ) 6.3

f Number of degrees of freedom Tables C.2 to C5

F Fisher distributed stochastic variable 4.2, 6.1, 6.3

F Tabulated value of F (linearity of thermal endurance graph) 4.4, 6.3

F Tabulated value of F (linearity of property graph – significance 0,05) 6.1

F Tabulated value of F (linearity of property graph – significance 0,005) 6.1

g Order number of ageing time for destructive tests 6.1

h Order number of property value for destructive tests 6.1

HIC Halving interval at temperature equal to TI 4.3, 7

HIC Halving interval corresponding to TI 7.3

g g

i Order number of exposure temperature 4.1, 6.2

j Order number of time to end-point 4.1, 6.2

k Number of ageing temperatures 4.1, 6.2

m Number of specimens aged at temperature ϑ 4.1, 6.1

i i

N Total number of times to end-point 6.2

n Number of property values in group aged for time τ 6.1

g g

n Number of values of y at temperature ϑ 4.1, 6.1

i i

---------------------- Page: 9 ----------------------

60216-3 Ed. 2/CDV © IEC – 10 –

p Mean value of property values in selected groups 6.1

p Value of diagnostic property 6.1

P Significance level of χ distribution 4.4, 6.3.1

p Value of diagnostic property at end-point for destructive tests 6.1

p Mean of property values in group aged for time τ 6.1

g g

p Individual property value 6.1

q Base of logarithms 6.3

r Number of ageing times selected for inclusion in calculation

(destructive tests) 6.1

r Square of correlation coefficient 6.2.3

2 2

s Weighted mean of s and s 6.3

1 2

2 2

s Weighted mean of s , pooled variance within selected groups 4.3, 6.1 - 6.3

1 1i

2 2

(s ) Adjusted value of s 4.4, 6.3

s Variance of property values in group aged for time τ 6.1

s Variance of y values at temperature ϑ 4.3, 6.2

ij i

s Variance about regression line 6.1 - 6.3

s Adjusted value of s 6.3

s Intermediate constant 6.3

Variance of Y 6.3

t Student distributed stochastic variable 6.3

t Adjusted value of t (incomplete data) 6.3

TC Lower 95 % confidence limit of TI 4.4, 7

TC Adjusted value of TC 7.1

TI Temperature Index 4.3, 7

TI Temperature Index at 10 kh 7.1

TI Adjusted value of TI 7.3

TI Temperature index obtained by graphical means or

without defined confidence limits 7.3

x Independent variable: reciprocal of thermodynamic temperature

x Weighted mean value of x 6.2

X Specified value of x for estimation of y 6.3

X Estimated value of x at specified value of y 6.3

ˆ ˆ

X Upper 95 % confidence limit of X 6.3

x Reciprocal of thermodynamic temperature corresponding to ϑ 4.1, 6.1

i i

---------------------- Page: 10 ----------------------

60216-3 Ed. 2/CDV © IEC – 11 –

y Weighted mean value of y 6.2

y Dependent variable: logarithm of time to end-point

Y Estimated value of y at specified value of x 6.3

Y Specified value of y for estimation of x 6.3

ˆ ˆ

Y Lower 95 % confidence limit of Y 6.3

y Mean values of y at temperature ϑ 4.3, 6.2

ij i

y Value of y corresponding to τ 4.1, 6.1

ij ij

z Mean value of z 6.1

z Logarithm of ageing time for destructive tests – group g 6.1

α Censored data coefficient for variance 4.3, 6.2

β Censored data coefficient for variance 4.3, 6.2

ε Censored data coefficient for variance of mean 4.3, 6.2

Θ The temperature 0 °C on the thermodynamic scale (273,15 K) 4.1, 6.1

ϑ Estimate of temperature for temperature index 6.3.3

ˆ ˆ

ϑ Confidence limit of ϑ 6.3.3

ϑ Ageing temperature for group i 4.1, 6.1

µ Censored data coefficient for mean 4.3, 6.2

µ (x) Central second moment of x values 6.2, 6.3

ν Total number of property values selected at one ageing temperature 6.1

τ Time selected for estimate of temperature 6.3

τ Times to end-point 6.3

2 2

χ χ -distributed stochastic variable 6.3

4 Principles of calculations

4.1 General principles

The general calculation procedures and instructions given in clause 6 are based on the principles

set out in IEC 60493-1. These may be simplified as follows (see 3.7.1 of IEC 60493-1):

a) the relation between the mean of the logarithms of the times taken to reach the specified

end-point (times to end-point) and the reciprocal of the thermodynamic (absolute)

temperature is linear;b) the values of the deviations of the logarithms of the times to end-point from the linear

relation are normally distributed with a variance which is independent of the ageing

temperature.The data used in the general calculation procedures are obtained from the experimental data

by a preliminary calculation. The details of this calculation are dependent on the character of

the diagnostic test: non-destructive, proof or destructive (see 4.2). In all cases the data

comprise values of x, y, m, n and k,---------------------- Page: 11 ----------------------

60216-3 Ed. 2/CDV © IEC – 12 –

where

x = 1/(ϑ + Θ ) = reciprocal of thermodynamic value of ageing temperature ϑ in °C;

i i 0 iy = log τ = logarithm of value of time (j) to end-point at temperature ϑ ;

ij ij i

n = number of y values in group number i aged at temperature ϑ ;

i i

m = number of samples in group number i aged at temperature ϑ (different from n for

i i icensored data);

k = number of ageing temperatures or groups of y values.

NOTE Any number may be used as the base for logarithms, provided consistency is observed throughout

calculations. The use of natural logarithms (base e) is recommended, since most computer programming

languages and scientific calculators have this facility.4.2 Preliminary calculations

In all cases, the reciprocals of the thermodynamic values of the ageing temperatures are

calculated as the values of x .The values of y are calculated as the values of the logarithms of the individual times to end-

point τ obtained as described below.In many cases of non-destructive and proof tests, it is advisable for economic reasons, (for

example, when the scatter of the data is high) to stop ageing before all specimens have

reached the end-point, at least for some temperature groups. In such cases, the procedure for

calculation on censored data (see 6.2.1.2) shall be carried out on the (x, y) data available.

Groups of complete and incomplete data or groups censored at a different point for each

ageing temperature may be used together in one calculation in 6.2.1.2.4.2.1 Non-destructive tests

Non-destructive tests, (for example, loss of mass on ageing) give directly the value of the

diagnostic property of each specimen each time it is measured at the end of an ageing period.

The time to end-point τ is therefore available, either direct or by linear interpolation between

ij,consecutive measurements.

4.2.2 Proof tests

The time to end-point τ for an individual specimen is taken as the mid-point of the ageing

period immediately prior to reaching the end-point (6.3.2 of IEC 60216-1).4.2.3 Destructive tests

When destructive test criteria are employed, each test specimen is destroyed in obtaining a

property value and its time to end-point cannot therefore be measured direct.To enable estimates of the times to end-point to be obtained, the assumptions are made that

in the vicinity of the endpointa) the relation between the mean property values and the logarithm of the ageing time is

approximately linear;---------------------- Page: 12 ----------------------

60216-3 Ed. 2/CDV © IEC – 13 –

b) the values of the deviations of the individual property values from this linear relation are

normally distributed with a variance which is independent of the ageing time;c) the curves of

**...**

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