IEC 60371-3-2:2005

Insulating materials based on mica - Part 3: Specifications for individual materials - Sheet 2: Mica paper

IEC 60371-3-2:2006 gives requirements for electrical insulating materials made from mica paper which is to be processed for built-up mica materials according to IEC 60371-1, such as rigid flat mica materials, flexible mica materials, curable flexible mica materials and shaped pieces. This second edition cancels and replaces the first edition, published in 1991, and constitutes a technical revision. The main changes with regard to the previous edition include adjustments to align this standard with changes included in the latest edition of IEC 60371-2. Keywords: electrical insulating materials, mica paper

Matériaux isolants à base de mica - Partie 3: Spécifications pour matériaux particuliers - Feuille 2: Papier de mica

L'IEC 60371-3-2:2006 fournit des exigences pour les matériaux isolants électriques réalisés en papier de mica qui est utilisé pour la fabrication de matériaux à base de mica conformément à la CEI 60371-1-1, tels que des plaques rigides de matériaux à base de mica, des matériaux souples à base de mica, des matériaux souples durcissables à base de mica et des pièces de forme. Cette seconde édition annule et remplace la première édition parue en 1991 dont elle constitue une révision technique. Les principales modifications par rapport à l'édition antérieure incluent des ajustements pour faire correspondre la présente norme aux modifications de la dernière édition de la CEI 60371-2. Mots clés: matériaux isolants électriques, papier de mica

General Information

• Status: Published
• Publication Date: 23-Oct-2005
• ICS: 29.035.10 - Paper and board insulating materials
• ICS: 29.035.50 - Mica based materials
• Technical Committee: TC 15 - Solid electrical insulating materials
• Drafting Committee: MT 11 - TC 15/MT 11
• Current Stage: PPUB - Publication issued
• Start Date: 24-Oct-2005
• Completion Date: 15-Mar-2006

Overview

IEC 60371-3-2:2005 specifies requirements for mica paper used as electrical insulating materials and intended for processing into built-up mica products (rigid flat mica, flexible mica, curable flexible mica and shaped pieces). This second edition (2005) replaces the 1991 edition and aligns the mica paper specification with updates in IEC 60371-2 (methods of test). The standard sets classification, delivery, marking and test requirements to ensure reproducible performance of mica-based electrical insulating materials.

Key topics and requirements

• Scope and purpose: Requirements for mica paper used in built-up insulating materials for electrical equipment; users must verify material suitability for their specific application.
• Classification & designation: Mica papers are designated MPM (muscovite) or MPP (phlogopite) and grouped into four classes (e.g., MPM class 1–3, MPP class 4). Example designation: MPM-1050 (class 1, 50 g/m²).
• Forms of delivery & marking: Supplied in rolls or sheets; rolls must be wound to avoid telescoping. Marking must include manufacturer, batch/roll number, designation and net mass.
• Quality & handling: Sheets/rolls must be flat, smooth and free from defects, contamination and splices. Packaging to protect during transport and storage is required.
• Test methods & properties (referenced standards used):
  • Mass per unit area (IEC 60554-2 / ISO 536)
  • Thickness and bulk density (ISO 534)
  • Air porosity (ISO 5636-5, Gurley method) - illustrated ranges in the standard (Figure 1)
  • Penetration (IEC 60371-2) - illustrated (Figure 2)
  • Tensile strength (IEC 60554-2) - illustrated (Figure 3)
  • Conductivity of aqueous extract (IEC 60589)
  • Loss of mass at 500 °C (IEC 60371-2)
• Sampling & specimen preparation: Specific sample sizes and preparation rules (remove outer layers from rolls; cut to represent full width; die cutting preferred).

Applications and who uses it

• Practical applications: Specification is used for mica paper that becomes built-up mica insulation in electrical equipment such as rotating machines, transformers, high-voltage assemblies and other components requiring high-temperature and dielectric stability.
• Primary users: mica paper manufacturers, material suppliers, OEMs (electrical equipment designers), procurement/specification engineers, test laboratories and certification bodies.
• Value: Helps ensure consistent electrical insulating materials, supports material selection, procurement contracts and compliance with agreed performance criteria.

Related standards

• IEC 60371-1 (Definitions and general requirements)
• IEC 60371-2 (Methods of test)
• IEC 60554-2, IEC 60589, ISO 534, ISO 536, ISO 5636-5

Keywords: electrical insulating materials, mica paper, IEC 60371-3-2, mica insulation, mica paper specification.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 60371-3-2
Second edition
2005-10
Insulating materials based on mica –
Part 3:
Specifications for individual materials –
Sheet 2: Mica paper
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
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edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
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INTERNATIONAL IEC
STANDARD 60371-3-2
Second edition
2005-10
Insulating materials based on mica –
Part 3:
Specifications for individual materials –
Sheet 2: Mica paper
 IEC 2005  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: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
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International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 60371-3-2  IEC:2005(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 General .6
3.1 Classification and designation .6
3.2 Standard forms of delivery.7
3.3 Marking .7
4 General requirements .7
4.1 Conditions as received .7
4.2 Properties .8
5 Tests .8
5.1 Test specimens .8

Figure 1 – Mica paper – Air porosity .10
Figure 2 – Mica paper – Penetration .11
Figure 3 – Mica paper – Tensile strength .12

Table 1 – Dimensions of test specimens .8
Table 2 – Requirements for mica paper .9

60371-3-2  IEC:2005(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INSULATING MATERIALS BASED ON MICA –

Part 3: Specifications for individual materials –
Sheet 2: Mica paper
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
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equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
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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 60371-3-2 has been prepared by IEC technical committee 15:
Standards on specifications for electrical Insulating materials.
This second edition cancels and replaces the first edition, published in 1991, and constitutes
a technical revision.
The main changes with regard to the previous edition include adjustments to align this
standard with changes included in the latest edition of IEC 60371-2.

– 4 – 60371-3-2  IEC:2005(E)
The text of this standard is based on the following documents:
FDIS Report on voting
15/227/FDIS 15/245/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.
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 bilingual version of this publication may be issued at a later date.

60371-3-2  IEC:2005(E) – 5 –
INTRODUCTION
This part of IEC 60371 forms part of a series which deals with insulatin
...

IEC 60371-3-2 ®
Edition 2.0 2005-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Insulating materials based on mica –
Part 3: Specifications for individual materials –
Sheet 2: Mica paper
Matériaux isolants à base de mica –
Partie 3: Spécifications pour matériaux particuliers –
Feuille 2: Papier de mica
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IEC 60371-3-2 ®
Edition 2.0 2005-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Insulating materials based on mica –

Part 3: Specifications for individual materials –

Sheet 2: Mica paper
Matériaux isolants à base de mica –

Partie 3: Spécifications pour matériaux particuliers –

Feuille 2: Papier de mica
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX M
ICS 29.035.10; 29.035.50 ISBN 978-2-8322-1596-8

– 2 – IEC 60371-3-2:2005 © IEC 2005
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 General . 6
3.1 Classification and designation . 6
3.2 Standard forms of delivery . 7
3.3 Marking . 7
4 General requirements . 7
4.1 Conditions as received . 7
4.2 Properties . 8
5 Tests . 8
5.1 Test specimens . 8
5.1.1 Sampling and preparation of test specimens . 8
5.1.2 Dimensions of test specimens . 8

Figure 1 – Mica paper – Air porosity . 10
Figure 2 – Mica paper – Penetration . 11
Figure 3 – Mica paper – Tensile strength . 12

Table 1 – Dimensions of test specimens . 8
Table 2 – Requirements for mica paper . 9

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INSULATING MATERIALS BASED ON MICA –

Part 3: Specifications for individual materials –
Sheet 2: Mica paper
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 60371-3-2 has been prepared by IEC technical committee 15:
Standards on specifications for electrical Insulating materials.
This bilingual version (2014-05) corresponds to the English version, published in 2005-10.
This second edition cancels and replaces the first edition, published in 1991, and constitutes
a technical revision.
The main changes with regard to the previous edition include adjustments to align this
standard with changes included in the latest edition of IEC 60371-2.

– 4 – IEC 60371-3-2:2005 © IEC 2005
The text of this standard is based on the following documents:
FDIS Report on voting
15/227/FDIS 15/245/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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.
INTRODUCTION
This part of IEC 60371 forms part of a series which deals with insulating materials built up
from mica splittings or mica paper with or without reinforcement, and with mica paper in its
pure state for use in electrical equipment.
IEC 60371 consists of three parts under the main title Specification for insulating materials
based on mica:
Part 1: Definitions and general requirements
Part 2: Methods of test
Part 3: Specifications for individual materials
This standard contains one of the sheets comprising part 3, as follows:
Sheet 2: Mica paper
– 6 – IEC 60371-3-2:2005 © IEC 2005
INSULATING MATERIALS BASED ON MICA –

Part 3: Specifications for individual materials –
Sheet 2: Mica paper
1 Scope
This part of IEC 60371 gives requirements for electrical insulating materials made from mica
paper which is to be processed for built-up mica materials according to IEC 60371-1, such as
rigid flat mica materials, flexible mica materials, curable flexible mica materials and shaped
pieces.
Materials which conform to this specification meet established levels of performance.
However, the selection of a material by a user for a specific application should be based on
the actual requirements necessary for adequate performance in that application and not
based on this specification alone.
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 60371-1:2003, Specification for insulating materials based on mica – Part 1: Definitions
and general requirements
IEC 60371-2:2004, Specification for insulating materials based on mica – Part 2: Methods of
test
IEC 60554-2:2001, Cellulosic papers for electrical purposes – Part 2: Methods of test
IEC 60589:1977, Methods of test for the determination of ionic impurities in electrical
insulating materials by extraction with liquids
ISO 534:2005, Paper and board – Determination of thickness and apparent bulk density or
apparent sheet density
ISO 536:1995, Paper and board – Determination of grammage
ISO 5636-5:2003, Paper and board – Determination of air permeance and air resistance
(medium range) – Part 5: Gurley method
3 General
3.1 Classification and designation
Mica papers are classified in several types depending on the nature of the mica minerals used
and the manufacturing procedure. These types have different characteristics as regards
thickness, mass per unit area and physical and chemical properties.

The nature of the mica minerals is designated by the symbols MPM or MPP, as follows:
MPM = mica paper, muscovite;
MPP = mica paper, phlogopite.
Since it would not be possible to harmonize the many-sided interests connected with mica
paper made by diverse procedures, the following four main classes have been chosen:
Class 1 MPM: mica paper based on calcined muscovite, chemical process;
Class 2 MPM: mica paper based on calcined muscovite, mechanical process;
Class 3 MPM: mica paper based on uncalcined muscovite;
Class 4 MPP: mica paper based on uncalcined phlogopite.
The above classes are distinguished from each other by characteristic properties such as
porosity, penetration and tensile strength. These properties are plotted versus mass per unit
area in Figures 1 to 3 showing the possible ranges of the four different classes.
NOTE The base materials for MPM-types classes 1 and 2 can be blended in order to achieve a mica paper with
characteristics lying between class 1 and class 2 types, and should be subject to contract.
The letter symbols for the nature of the mica minerals are followed by four digits indicating the
class (first digit) and the mass per unit area (second to fourth digits).
Example: designation of mica paper based on calcined muscovite (MPM), with a mass per unit
area of 50 g/m , whose properties meet the requirements given in Table 2 for class 1: Mica
paper - IEC 60371-3-2 MPM-1050.
3.2 Standard forms of delivery
Mica papers may be supplied in rolls or sheet form.
3.3 Marking
Rolls and packets of mica paper supplied as complying with this specification shall be marked
with the following:
– supplier, manufacturer and trade name;
– batch/roll number;
– designation in accordance with 3.1;
– net mass of roll or packet.
The marks shall be durable and fixed in such a manner that they can be read until the mica
paper is completely unrolled, or the packet has been completely used.
4 General requirements
The mica paper shall comply with the requirements of IEC 60371-1 and with this standard.
4.1 Conditions as received
Mica paper shall be supplied wound on cores sufficiently tightly to enable the material to be
unwound smoothly without telescoping. On receipt, the roll end shall form a plane circular
surface with no apparent telescoping.
The difference between the roll width and the paper width shall be subject to contract between
purchaser and supplier.
– 8 – IEC 60371-3-2:2005 © IEC 2005
The width of the rolls and their core and outer diameter shall be subject to contract between
purchaser and supplier.
The materials should be packaged to ensure adequate protection during transport, handling
and storage. Any necessary packing requirements should be subject to the purchase contract.
Mica paper in sheets or when unrolled shall be flat and smooth, free from defects such as
compressed spots, holes, creases and contamination, e.g. large hard mica particles and
electrically conductive inclusions.
Splices in mica paper are not acceptable.
4.2 Properties
When tested according to Clause 5, the measured values shall conform with the requirements
given in Table 2.
5 Tests
5.1 Test specimens
The number of test specimens necessary for each test is indicated in the test method.
If delivered in rolls, the two outermost layers of mica paper shall be removed prior to taking a
sample of about 1 m .
If mica paper is delivered in sheets, one sheet constitutes the specimen which has to meet
the requirements for the respective batch.
5.1.1 Sampling and preparation of test specimens
For any test, the specimens shall be cut in such a manner that the full width of the material is
represented. The cut edge shall be straight and free from tears and cracks. Die cutting is
preferred when possible.
5.1.2 Dimensions of test specimens
The dimensions of the test specimens for each test are given in Table 1.
The mean thickness is the average of ten thickness measurements made on the test sheet or
sample, at approximately equispaced locations across the diagonal of the sheet or sample.
Table 1 – Dimensions of test specimens
Test method Test specimens
Requirements
Publication Clause or Dimensions Tolerances
subclause mm mm
Mass per unit area IEC 60554-2 3
100 × 100
± 0,2
Conductivity of the
IEC 60589
aqueous extract
alternatively
±0,2
Loss of mass at 500 °C
IEC 60371-2 7.4.1
∅ 113
Tensile strength IEC 60554-2 5 15 × 250 ± 0,2
Air porosity ISO 5636-5 ± 1
50 × 120
Penetration IEC 60371-2 20 ± 1
75 × 75
Table 2 – Requirements for mica paper
Class Range Preferred Mass per unit area Thickness Air Impreg- Conduc- Loss of Tensile
of mass per types porosity nation time tivity mass strength
Nominal
...