Electrical insulation systems - Thermal evaluation of modifications to an established electrical insulation system (EIS) - Part 2: Form-wound EIS

IEC 61858-2:2014 lists the required test procedures for qualification of modifications of an established electrical insulation system (EIS) with respect to its thermal classification. This standard is applicable to EIS used in form-wound electrotechnical devices. The test procedures are comparative in that the performance of a candidate EIS is compared to that of a reference EIS, which has proven service experience in accordance with IEC 60505 or has been evaluated by one of the procedures given in IEC 60085 and IEC 60034-18-31.

Systèmes d'isolation électrique - Évaluation thermique des modifications apportées à un système d'isolation électrique (SIE) éprouvé - Partie 2: Système d'isolation électrique à enroulements préformés

L'IEC 61858-2:2014 énumère les procédures d'essai requises pour la qualification des modifications qui ont été apportées à un système d'isolation électrique (SIE) éprouvé, pour ce qui concerne sa classification thermique. La présente norme s'applique aux SIE utilisés dans les dispositifs électrotechniques à enroulements préformés. Les procédures d'essai sont comparatives en ce qu'elles se font par comparaison des performances d'un SIE candidat avec celles d'un SIE de référence dont l'expérience en service a été démontrée conformément à l'IEC 60505, ou qui a été évalué par l'une des procédures décrites dans l'IEC 60085 et l'IEC 60034-18-31.

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Status
Published
Publication Date
11-Feb-2014
Current Stage
PPUB - Publication issued
Start Date
12-Feb-2014
Completion Date
12-Feb-2014
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IEC 61858-2
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical insulation systems – Thermal evaluation of modifications to an
established electrical insulation system (EIS) –
Part 2: Form-wound EIS
Systèmes d'isolation électrique – Évaluation thermique des modifications
apportées à un système d’isolation électrique (SIE) éprouvé –
Partie 2: Système d’isolation électrique à enroulements préformés
IEC 61858-2:2014-02(EN-FR)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61858-2
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical insulation systems – Thermal evaluation of modifications to an
established electrical insulation system (EIS) –
Part 2: Form-wound EIS
Systèmes d'isolation électrique – Évaluation thermique des modifications
apportées à un système d’isolation électrique (SIE) éprouvé –
Partie 2: Système d’isolation électrique à enroulements préformés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 29.080.30 ISBN 978-2-8322-1394-0

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – 61858-2 © IEC:2014
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

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

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

3 Terms and definitions ...................................................................................................... 7

4 General considerations .................................................................................................... 9

5 Substitution of phase insulation and/or ground insulation ............................................... 11

5.1 Generically identical ............................................................................................. 11

5.2 Substitution or addition of selected components and additives .............................. 11

5.3 Reduction of thickness .......................................................................................... 11

6 Substitution of winding wire ........................................................................................... 12

6.1 Winding wire ......................................................................................................... 12

6.2 Substitution of conductor material ......................................................................... 13

6.3 Alternate winding wire ........................................................................................... 13

7 Substitution of impregnating resin/varnish ..................................................................... 13

8 Evaluation of additions .................................................................................................. 13

9 Procedure C – Single-point thermal ageing test ............................................................. 13

9.1 Test objects .......................................................................................................... 13

9.2 Establishing the EIS relative thermal endurance index (EIS RTE) ......................... 13

9.3 Interpretation of results ......................................................................................... 14

10 Full thermal aging test (procedure D) ............................................................................. 14

Annex A (normative) Classes of winding wire ....................................................................... 15

Annex B (informative) Visual representation of form-wound coil manufacturing process ....... 16

Bibliography .......................................................................................................................... 22

Figure 1 – Overview of evaluation methods ........................................................................... 10

Figure 2 – Substitution of phase and ground insulation ......................................................... 11

Figure 3 – Substitution of winding wire .................................................................................. 12

Figure 4 – Substitution of conductor material ........................................................................ 12

Figure B.1 – Rectangular winding wire shaped into un-formed coil on coil forming

machine ................................................................................................................................ 16

Figure B.2 – Un-formed coil being wrapped with a protective fabric ...................................... 17

Figure B.3 – Un-formed coil completely wrapped with protective fabric ................................. 17

Figure B.4 – Coil forming machine stretches and bends oval coil to formed shape coil

in the shaping apparatus ....................................................................................................... 18

Figure B.5 – Formed coil with protective layer removed ........................................................ 18

Figure B.6 – Close-up of formed coil’s knuckle insulation ...................................................... 19

Figure B.7 – Formed coil with multiple layers of insulation .................................................... 19

Figure B.8 – Formed coils placed into the form-wound test specimen or Formette ................ 20

Figure B.9 – Insulation details ............................................................................................... 21

Table A.1 – Winding wire type – Rectangular conductor ........................................................ 15

---------------------- Page: 4 ----------------------
61858-2 © IEC:2014 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL INSULATION SYSTEMS –
THERMAL EVALUATION OF MODIFICATIONS TO
AN ESTABLISHED ELECTRICAL INSULATION SYSTEM (EIS) –
Part-2: Form-wound EIS
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

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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 61858-2 has been prepared by IEC technical committee 112:

Evaluation and qualification of electrical insulating materials and systems.
The text of this standard is based on the following documents:
CDV Report on voting
112/253/CDV 112/274/RVC

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.

---------------------- Page: 5 ----------------------
– 4 – 61858-2 © IEC:2014

A list of all parts in the IEC 61858 series, published under the general title Electrical

insulation systems – Thermal evaluation of modifications to an established insulation system

(EIS), can be found on the IEC website.

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

the stability 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 6 ----------------------
61858-2 © IEC:2014 – 5 –
INTRODUCTION

This International Standard describes procedures for the evaluation of changes to an

established electrical insulation system (EIS) for form-wound electro technical devices and

the effect of these changes on the thermal classification of the established EIS.

This Part 2 of IEC 61858 is for form-wound EIS. Part 1 of IEC 61858 addresses modifications

of wire-wound EIS.

General principles for evaluation and qualification of EIS can be found in IEC 60505. Unless

the procedures of this standard indicate otherwise, the principles of IEC 60505 should be

followed.
---------------------- Page: 7 ----------------------
– 6 – 61858-2 © IEC:2014
ELECTRICAL INSULATION SYSTEMS –
THERMAL EVALUATION OF MODIFICATIONS TO
AN ESTABLISHED ELECTRICAL INSULATION SYSTEM (EIS) –
Part-2: Form-wound EIS
1 Scope

This part of IEC 61858 lists the required test procedures for qualification of modifications of

an established electrical insulation system (EIS) with respect to its thermal classification. This

standard is applicable to EIS used in form-wound electrotechnical devices. The test

procedures are comparative in that the performance of a candidate EIS is compared to that of

a reference EIS, which has proven service experience in accordance with IEC 60505 or has

been evaluated by one of the procedures given in IEC 60085 and IEC 60034-18-31.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60085:2007, Electrical insulation – Thermal evaluation and designation

IEC 60034-18-31:2012, Rotating electrical machines – Part 18-31: Functional evaluation of

insulation systems – Test procedures for form-wound windings – Thermal evaluation and

classification of insulation systems used in rotating machines

IEC 60216-5, Electrical insulating materials – Thermal endurance properties – Part 5:

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

IEC 60216-6, Electrical insulating materials – Thermal endurance properties – Part 6:

Determination of thermal endurance indices (TI and RTI) of an insulating material using the

fixed time frame method
IEC 60317 (all parts), Specifications for particular types of winding wires

IEC 60317-16, Specifications for particular types of winding wires – Part 16: Polyester

enamelled rectangular copper wire, class 155
(withdrawn)

IEC 60317-17, Specifications for particular types of winding wires – Part 17: Polyvinyl acetal

enamelled rectangular copper wire, class 105

IEC 60317-18, Specifications for particular types of winding wires – Part 18: Polyvinyl acetal

enamelled rectangular copper wire, class 120

IEC 60317-27, Specifications for particular types of winding wires – Part 27: Paper tape

covered rectangular copper wire
———————
Withdrawn in 2012.
---------------------- Page: 8 ----------------------
61858-2 © IEC:2014 – 7 –

IEC 60317-28, Specifications for particular types of winding wires – Part 28: Polyesterimide

enamelled rectangular copper wire, class 180

IEC 60317-29, Specifications for particular types of winding wires – Part 29: Polyester or

polyesterimide overcoated with polyamide-imide enamelled rectangular copper wire, class 200

IEC 60317-30, Specifications for particular types of winding wires – Part 30: Polyimide

enamelled rectangular copper wire, class 220
(withdrawn)

IEC 60317-31, Specifications for particular types of winding wires – Part 31: Glass-fibre

wound, polyester or polyesterimide varnish-trated, bare or enamelled rectangular copper wire,

temperature index 180

IEC 60317-32, Specifications for particular types of winding wires – Part 32: Glass-fibre

wound resin or varnish impregnated, bare or enamelled rectangular copper wire, temperature

index 155

IEC 60317-33, Specifications for particular types of winding wires – Part 33: Glass-fibre

wound resin or varnish impregnated, bare or enamelled rectangular copper wire, temperature

index 200

IEC 60317-39, Specifications for particular types of winding wires – Part 39: Glass-fibre

braided, polyester or polyesterimide varnish-treated, bare or enamelled rectangular copper

wire, temperature index 180

IEC 60317-40, Specifications for particular types of winding wires – Part 40: Glass-fibre

braided, silicone varnish-tratead, bare or enamelled rectangular copper wire, temperature

index 200

IEC 60317-44, Specifications for particular types of winding wires – Part 44: Aromatic

polyimide tape wrapped rectangular copper wire, class 240

IEC 60317-47, Specifications for particular types of winding wires – Part 47: Aromatic

polyimide enamelled rectangular copper wire, class 240

IEC 60317-53, Specifications for particular types of winding wires – Part 53: Aromatic

polyamide (aramid) tape wrapped rectangular copper wire, temperature index 220

IEC 60317-58, Specifications for particular types of winding wires – Part 58: Polyamide-imide

enamelled rectangular copper wire, class 220
IEC 60505, Evaluation and qualification of electrical insulation systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
enamelled winding wire

insulated conductors, round or shaped, where the insulation is applied in a liquid form and

applied to the conductor, made in accordance with the IEC 60317 series
———————
Withdrawn in 2009.
---------------------- Page: 9 ----------------------
– 8 – 61858-2 © IEC:2014
3.2
wrapped insulated winding wire

insulated conductor, round or shaped, where the insulation is applied as a tape, with or

without an adhesive, made from a film or a paper and applied to the conductor, made in

accordance with the IEC 60317 series
3.3
random wire-wound coils

coils for use in an electrotechnical device made with enamelled winding wire without concern

for the location of the turns
3.4
precision wire-wound coils

coils for use in an electrotechnical device made with enamelled winding wire or sheet

conductor and insulation with each turn positioned in a specific and successive way

3.5
form-wound coils
rectangular wire formed to a coil for use in an electrotechnical device

Note 1 to entry: Usually made with an insulated conductor this may be enamelled, fibrous wrapped or enamelled

with fibrous wrapping. Afterwards the coil is wound it receives multiple layers of tape wrapped insulation and is

vacuum- or vacuum-pressure impregnated with a resin, or wrapped with sufficient layers of a pre-impregnated B-

stage tape and processed using resin-rich method.
3.6
wire-wound electrical insulation system

EIS evaluated with the wire wound coils that are either random or precision wound; not form

wound coils
3.7
wire-wound winding electrotechnical device
electrotechnical device designed utilizing a wire-wound EIS
3.8
electrical insulation system
EIS

insulating structure containing one or more electrical insulating materials (EIM) together with

associated conducting parts employed in an electrotechnical device
3.9
electrical insulating material
EIM

material with negligibly low electric conductivity, used to separate conducting parts at different

electrical potentials
3.10
candidate EIS
EIS under evaluation concerning its thermal endurance for service capability
3.11
reference EIS

established EIS evaluated on the basis of either a known service experience record or a

known comparative functional evaluation
3.12
EIS assessed thermal endurance index
EIS ATE

numerical value of temperature in degrees Celsius for the reference EIS as derived from

known service experience or a known comparative functional evaluation
---------------------- Page: 10 ----------------------
61858-2 © IEC:2014 – 9 –
3.13
EIS relative thermal endurance index
EIS RTE

numerical value of the temperature in degrees Celsius of the candidate EIS which is relative

to the known EIS ATE of a reference EIS, when both EIS are subjected to the same ageing

and diagnostic procedures in a comparative test
4 General considerations

This standard provides relatively low cost and short-time methods by which the user can

make modifications to an established EIS by evaluating

a) the impact on the thermal life of the EIS if the thickness of an EIM is changed,

b) the compatibility, under thermal stress, of a substituted EIM,

c) the compatibility, under thermal stress, of other components used in intimate contact with

an established EIS.

EIM thermal indices (ATE/RTE) can be established by testing in accordance with IEC 60216-5

or IEC 60216-6. According to IEC 60505, an EIS may be constructed with EIMs having

different thermal indices. The thermal class of the EIS is established through testing and may

be higher or lower than any of the individual components.

There may be more than one EIS in a particular apparatus. These EIS may have different

thermal classes.
---------------------- Page: 11 ----------------------
– 10 – 61858-2 © IEC:2014
Established EIS per IEC 60034-18-31
or IEC 60505
EIM modification of established EIS Evaluation of additions to
established EIS (8)
Addition of Addition
Change of
Substitution of EIM component
impregnating resin/ of other
thickness
varnish components
(5)
Impregnating
Phase or Ground Winding
resin/varnish
Insulation(5) Wire (6)
(7)
Substitution Substitution
allowed? allowed? (6.1)
Yes
No
Yes
Test per Clause 10
Single temperature Acceptable
aging test (Clause 9) results?
No
Yes
Acceptable
results? Can use in
EIS
No Yes
Modified EIS is acceptable
Test as new EIS according to IEC 60034-18-31
IEC 0519/14
Key
Single temperature EIS evaluation
No testing required
Full thermal aging EIS evaluation
Figure 1 – Overview of evaluation methods

NOTE Figure 1 provides guidance in selecting the proper clauses for evaluation of modifications to an established

form-wound EIS. Figure 1 serves as an overview for Clauses 5 to 8; Clauses 5 to 8 present details one category at

a time.

In Figures 2, 3, and 4, the following letters represent a test procedure as indicated below:

---------------------- Page: 12 ----------------------
61858-2 © IEC:2014 – 11 –
• A = Procedure A: no testing required;

• B = Procedure B: sealed tube compatibility test (only utilized in IEC 61858-1);

• C = Procedure C: single-point thermal aging test (Clause 9);
• D = Procedure D: full thermal aging test (Clause 10).
5 Substitution of phase insulation and/or ground insulation
Generically
identical (5.1.1)
Yes No
C D
IEC 0520/14
Figure 2 – Substitution of phase and ground insulation
5.1 Generically identical

"Generically identical" refers to both chemical and physical properties of the original and

alternate materials. The alternate material shall have equal or better mechanical and

electrical performance in regards to the thermal endurance.

Based on application of other properties, e.g. water permeability or process ability, these are

critical to the performance of the system and should be considered prior to substitution.

Basic chemical composition and physical identity can be established by analytical data based

on appropriate spectroscopic analysis such as IR complimented with thermogravimetric,

differential thermal analysis (DTA) and absorption analysis. The specific tests should be

agreed upon by the interested parties.

Substitution of generically identical EIMs is allowed if it meets the criteria of Clause 9.

5.2 Substitution or addition of selected components and additives

Substitution or addition of select additives (e.g. colorants, fillers, etc.) in an EIM may be

allowed with reduced or no additional testing if agreed upon by all interested parties.

An EIM evaluated as part of the established EIS, used in combination with another EIM or

other component, may be used based upon acceptable results when tested in accordance

with Clause 9. The thickness of the established EIM shall not be less than that which was

evaluated in the established EIS.
5.3 Reduction of thickness

An EIM in the established EIS can be used at a reduced thickness if it is successfully

evaluated in accordance with Clause 9.

If none of the above conditions are met, full thermal aging in accordance with Clause 10 shall

be conducted.
---------------------- Page: 13 ----------------------
– 12 – 61858-2 © IEC:2014
6 Substitution of winding wire
Same chemical composition of
coating and equal or greater thermal
endurance rating (6.1 a)
Yes No
Same chemical composition
coating with equal or greater
thermal class rating but corners are
a different shape or radius (6.1 b)
No Yes
A C D
IEC 0521/14
Figure 3 – Substitution
...

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