Combined flexible materials for electrical insulation - Part 1: Definitions and general requirements
1Key Takeaways
This pari of IEC 626 contains the definitions related to and the general requirements to be fulfilled by combined flexible materials for electrical insulation. This standard does not include materials based on mica paper.
2Expert Interpretation
This in-depth analysis of the 3rd edition of the IEC 60626-1 international standard for electrical insulating composite flexible materials covers definitions, classifications, material requirements, technical specifications, and application guidelines. It also provides a detailed analysis of the laminate structure, performance requirements, and key quality control points of composite insulation materials, providing a professional reference for the design of insulation systems for electrical equipment.
IEC 60626-1 Standard Overview and Technical Background
IEC 60626-1:2009 is Part 1 of the International Electrotechnical Commission's series of standards for electrical insulating composite flexible materials. It specifically addresses composite flexible materials composed of two or more different insulating materials laminated together. The third edition of this standard, published in August 2009, supersedes the 1995 second edition and its 1996 amendment 1, reflecting the latest developments in insulation material technology.
Scope of Application and Core Definitions
This standard applies to composite flexible insulating materials composed of plastic film and/or fibrous materials (such as paper, woven or non-woven fabrics, whether or not impregnated). Notably, the standard explicitly excludes mica paper as a primary component, but allows its use as a supplementary material.
| Material Type | Definition | Application Characteristics | Standard Reference |
|---|---|---|---|
| Full Width Material | Material in production width, typically around 1 meter | Suitable for large-scale production | Clause 3.1 |
| Slit Material (Strip) | Material cut from full width material | To facilitate installation in specific applications | Clause 3.2 |
| Double Layer Material | Laminated from two layers of insulating material | Basic composite structure | Clause 3.3 |
| Three-layer material | Laminated by three layers of insulating material | Enhanced performance combination | Clause 3.4 |
| Four-layer material | Laminated by four layers of insulating material | Complex functional requirements | Clause 3.5 |
Material classification and naming system
The standard establishes a systematic material naming method, using code letter combinations to identify material forms and properties. The main component codes include: F (film), P (paper and nonwoven fabrics and mats), C (woven fabrics) and A (adhesives).
| Material form | Code | Material properties | Code | IEC standard reference |
|---|---|---|---|---|
| Film | F | Polyethylene terephthalate | PET | IEC 60674-3-2 |
| Film | F | Polyethylene naphthalate | PEN | IEC 60674-3-8 |
| Film | F | Polyimide | PI | IEC 60674-3-4 |
| Paper | P | Cellulose Paper | C | IEC 60554-3-1 |
| Paper | P | Aramid Paper | PAa | IEC 60819-3-3 |
General Technical Requirements and Quality Control
The standard sets comprehensive technical requirements for composite flexible insulation materials to ensure their reliability and safety in electrical equipment.
Appearance Quality Requirements
The material surface should be uniform, reasonably smooth, and essentially free of defects such as bubbles, pinholes, creases, and blemishes. Materials within the same batch should be consistent, with performance meeting the standard limits throughout the entire length of the sheet or roll.
Physical Property Requirements
Materials in roll form must be capable of unrolling without damage, and all composite materials must be free of conductive particles and other undesirable inclusions. Materials in sheet form should be essentially warp-free, but attention should be paid to the "curl setting" phenomenon of the material after lamination.
Dimensional Specifications
Thickness and thickness tolerances are specified in IEC 60626-3. Other dimensions and tolerances must be determined by agreement between the purchaser and supplier. The core diameter of the roll is preferably 55mm, 76mm, or 150mm.
Technical Evolution Analysis of the Standard
Compared to the previous edition, the major technical updates of this third edition include: revised scope of application, clarified handling of mica paper, and updated common material tables, removing discontinued materials and introducing newer material types. This reflects the development trends of insulation material technology and changes in market demand.
| Version Comparison Dimensions | 2nd Edition (1995) | 3rd Edition (2009) | Technical Significance |
|---|---|---|---|
| Mica Paper Treatment | Not Clearly Excluded as a Main Component | Standardize Material Classification | |
| Material Table Contents | Includes Outdated Materials | Updated to Modern Materials | Reflects Technological Developments |
| Test Method Reference | Relatively Simple | Citation of the Latest Test Standards | Improve Test Accuracy |
| Safety Warning | Not Included | Safety Usage Warning Added | Emphasis on Safety Responsibility |
Implementation Recommendations and Engineering Applications
Based on the standard requirements, the following implementation recommendations are provided for engineering applications:
Material Selection Strategy
While materials meeting this specification achieve established performance levels, users should select materials for specific applications based on the actual requirements for adequate performance, not solely on this specification. Factors to consider include operating temperature, mechanical stress, environmental conditions, and electrical stress.
Quality Control Key Points
During implementation, key focus should be placed on: material consistency inspection, surface defect detection, detection of conductive particles, and storage condition control. For roll-formed materials, particular attention should be paid to the effects of storage time and temperature on material properties.
Packaging and Labeling Requirements
Each packaging unit shall be clearly labeled with: standard reference, type name, size specifications, manufacturing date, connection information, etc. Special supply conditions, such as shelf life requirements, shall be determined by negotiation between the purchaser and the supplier.
Analysis of the relevance of the standard system
The IEC 60626 series consists of three parts, which together constitute a complete standard system for composite flexible insulation materials:
- Part 1: Definitions and general requirements (IEC 60626-1) - Provides the basic framework
- Part 2: Test methods (IEC 60626-2) - Specifies performance verification procedures
- Part 3: Individual material specifications (IEC 60626-3) - Provides specific material requirements
This structured standard system ensures complete technical coverage from material definition to specific application, providing a reliable technical basis for the design and manufacture of electrical insulation systems.
Typical Application Case Analysis
Take PC/F-PET material as an example. This composite material, composed of cellulose paper layers and polyethylene terephthalate film laminated together, is widely used in motor slot insulation. Its combined structure provides both the impregnation properties of paper and the dielectric strength of film, demonstrating the synergistic advantages of composite materials.