MT 11 - TC 15/MT 11

IEC 60371-3-1:2006 applies to several types of rigid materials based on mica splittings or mica paper for commutator separators. These products shall be made from muscovite or phlogopite mica, built up from mica splittings or mica paper by the use of a suitable bonding medium. They are supplied in the following forms:
- sheets in the dimensions in which they are pressed or after trimming;
- strips cut from sheets;
- commutator separators having the shapes and dimensions and in the conditions ordered by the user. The normal manufacturing thicknesses lie between 0,3 mm and 2 mm. This third edition of IEC 60371-3-1 replaces the second edition, published in 1984, and constitutes a technical revision. The main changes with regard to the previous edition concern the modification of clause numbers to align with clause numbering in the latest edition of IEC 60371-2:2004. Keywords: mica splittings or mica paper for commutator separators, muscovite or phlogopite mica

IEC 60371-3-5:2005 gives requirements for electrical insulating materials made by combining mica paper with glass fabric and bonding them together with a small amount of epoxy resin. The material is supplied in a flexible state and is designed for use in conjunction with vacuum pressure impregnation (VPI) with compatible impregnates. The final cured properties will be primarily dependent on the VPI resin used. Two bond contents are specified:
- low bond with a resin content of (8 ± 3) %;
- medium bond with a resin content of (16 ± 3) %. 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. This second edition cancels and replaces the first edition, published in 1992, and constitutes a technical revision. The main changes with regard to the previous edition include adjustments needed to align this standard with changes included in the latest edition of IEC 60371-2. Keywords: electrical insulating materials, mica paper, glass fabric, vacuum pressure impregnation (VPI)

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

Defines the methods of test which are applicable to built-up mica materials, products based on them and mica paper. The main changes from the previous edition are as follows: a) All clauses re-numbered. b) Relevant template of ISO 67 has been added to this standard as Annex A. c) Clause 8: Tensile strength and elongation at break Procedure modified to give "rate of movement" instead of "time limit". Different rate of movement for raw mica as opposed to reinforced and/or impregnated mica. d) Clause 11: Stiffness Size of test specimen revised. Wording modified so that standard covers materials using carriers other than woven glass cloth and materials that are 3-ply. Revision of terms ""machine direction" and "transverse direction". (These were incorrect in second edition (1987).) e) Clause 13: Elastic compression and plastic compression Tolerance on measurement of height of stack changed to within 0,01 mm. Times for change in pressure in procedure changed to 1 min. f) Clause 16: Electric strength Modified in line with Amendment 1 (1994) to the second edition (1987). Changes relate to latest edition of IEC 60243-1. g) Clause 19: Detection of defects and conductive particles Revised subclause.

Gives definitions of terms used to describe built-up mica materials, products based on them and mica paper. It also deals with general requirements and conditions of supply. Changes in this new edition include: - a new Clause 2: Normative references; - under Clause 4: Description of material - new Subclause 4.2.1 to cover flexible mica material impregnated with B stage resin, - new Subclause 4.2.2 to cover flexible mica material, porous for post-impregnation; - a new Clause 5 covering general requirements and conditions of supply.