IEC TR 61857-2:2015

IEC TR 61857-2 ®
Edition 1.0 2015-04
TECHNICAL
REPORT
Electrical insulation systems – Procedures for thermal evaluation –
Part 2: Selection of the appropriate test method for evaluation and classification
of electrical insulation systems

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IEC TR 61857-2 ®
Edition 1.0 2015-04
TECHNICAL
REPORT
Electrical insulation systems – Procedures for thermal evaluation –

Part 2: Selection of the appropriate test method for evaluation and classification

of electrical insulation systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.080.30 ISBN 978-2-8322-2594-3

– 2 – IEC TR 61857-2:2015 © IEC 2015
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 General information . 6
4.1 Purpose of the evaluation . 6
4.2 Test objects . 7
4.3 Test stresses . 7
5 Design and development of the scope of work for the EIS evaluation. 7
6 Test methods for the evaluation and classification of EIS . 7

Table 1 – Evaluation for thermal stresses in air . 9
Table 2 – Standards for the modification of an established EIS . 10
Table 3 – Standards for special environmental applications . 10
Table 4 – For evaluation prior to the start of long-term thermal ageing . 10

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL INSULATION SYSTEMS –
PROCEDURES FOR THERMAL EVALUATION –

Part 2: Selection of the appropriate test method for evaluation
and classification of electrical insulation systems

FOREWORD
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example "state of the art".
IEC TR 61857-2, which is a technical report, has been prepared by IEC technical committee
112: Evaluation and qualification of electrical insulating materials and systems.

– 4 – IEC TR 61857-2:2015 © IEC 2015
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
112/312/DTR 112/318/RVC
Full information on the voting for the approval of this technical report 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.
A list of all parts in the IEC 61857 series, published under the general title Electrical insulation
systems – Procedures for thermal evaluation, 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 website 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 bilingual version of this publication may be issued at a later date.

ELECTRICAL INSULATION SYSTEMS –
PROCEDURES FOR THERMAL EVALUATION –

Part 2: Selection of the appropriate test method for evaluation
and classification of electrical insulation systems

1 Scope
This part of IEC 61857 gives guidelines to identify the appropriate test method to be used for
the evaluation of a proposed Electrical Insulation System (EIS). Some of the standards are for
evaluation and classification of the EIS, while other standards identify the appropriate method
to evaluate single or multi-factor stresses of a proposed or of an established EIS.
This Technical Report is applicable to existing or proposed EIS used in electrotechnical
products across a wide range of operating voltages of IEC Standards. The report takes care
to select the appropriate standard based on construction and intended operating conditions.
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 60034-18-21, Rotating electrical machines – Part 18-21: Functional evaluation of
insulation systems – Test procedures for wire-wound windings – Thermal evaluation and
classification
IEC 60034-18-31, 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 60505, Evaluation and qualification of electrical insulation systems
IEC 61857-1, Electrical insulation systems – Procedures for thermal evaluation – Part 1:
...