IEC 60317-12:2010

Overview

IEC 60317-12:2010 is an International Electrotechnical Commission (IEC) standard that specifies requirements for polyvinyl acetal enamelled round copper winding wire, classified as thermal class 120. This standard applies to enamelled copper wires coated with a polyvinyl acetal resin, which can be chemically modified so long as it retains the original resin's chemical identity and meets all stipulated wire requirements.

The document is part of the IEC 60317 series focused on particular types of winding wires and supplements IEC 60317-0-1:2008, which provides general requirements for enamelled round copper wire. The latest edition (third edition, 2010) introduces enhanced testing, including a new pin hole test requirement to ensure wire integrity.

Key Topics

Scope and Material

• Wire Type: Round copper wire with a polyvinyl acetal enamel coating.
• Thermal Class: Class 120 with a minimum temperature index of 120°C and heat shock resistance of at least 155°C.
• Coating: Single-layer sole coating based on polyvinyl acetal resin, which may be modified chemically but must maintain resin identity.
• Diameter Range:
  • Grade 1: 0.040 mm to 2.5 mm
  • Grade 2: 0.040 mm to 5.0 mm
  • Grade 3: 0.080 mm to 5.0 mm

Mechanical and Electrical Properties

• Electrical Resistance: Specified as per IEC 60317-0-1 with conditions for nominal conductor diameters.
• Elongation and Flexibility: The wire must meet minimum elongation and flexibility requirements, including springiness and adherence of enamel.
• Heat Shock Resistance: Enamel coating must show no cracking at heat shock temperatures (minimum 155°C) with specific mandrel bending tests.
• Cut-Through Resistance: The enamel coating must withstand continuous 2 minutes at 170°C without failure.
• Resistance to Abrasion: Defined by minimum force to failure, varying by nominal wire diameter and wire grade.
• Solderability and Solvent Resistance: The wire must maintain enamel integrity during soldering and resist common solvents.
• Pin Hole Test: Newly introduced for detecting microscopic holes in the enamel coating to prevent electrical breakdowns.

Testing and Quality Assurance

The standard defines methodologies to assess electrical insulation, mechanical robustness, and chemical resistance:

• Visual and dimensional inspections
• Electrical resistance and breakdown voltage tests
• Heat shock and thermal cycling
• Abrasion resistance under controlled forces
• Pin hole tests for enamel insulation integrity

Applications

Polyvinyl acetal enamelled round copper wire conforming to IEC 60317-12:2010 is widely used in:

• Electrical Motors and Generators: For efficient and durable winding insulation in thermal class 120 environments.
• Transformers and Inductors: Where thermal endurance and mechanical flexibility are critical.
• Electromechanical Devices: Requiring reliable copper windings with robust enamel coatings.
• High-Temperature Electrical Equipment: Suitable for applications with sustained moderate heat up to 120°C with transient heat shocks reaching 155°C.

Its resistance to abrasion, chemical solvents, and heat makes it ideal for use in demanding industrial, automotive, and household electrical appliances.

Related Standards

For comprehensive compliance and interface, the following IEC standards are relevant:

• IEC 60317-0-1:2008 – General requirements for enamelled round copper wire.
• IEC 60851 Series – Covers winding wire test methods.
• IEC 60264 Series – Specifies guidelines for packaging of winding wires.

Understanding IEC 60317-12 in conjunction with these related standards ensures proper selection, testing, and application of polyvinyl acetal enamelled copper wires in electrical and electronic equipment.

By following IEC 60317-12:2010, manufacturers and engineers ensure that enamelled copper winding wires meet international quality and safety requirements, optimized for performance in thermally demanding applications. This enhances product reliability, electrical safety, and operational longevity in electrotechnical installations.