IEC 60172:2015

Overview

IEC 60172:2015 is an international standard published by the International Electrotechnical Commission (IEC). It defines the test procedure for determining the temperature index of enamelled and tape wrapped winding wires. This standard offers a method based on the guidelines of IEC 60216-1 for assessing the thermal endurance properties of insulated wire materials by monitoring their reaction to AC proof voltage tests conducted in air at atmospheric pressure.

The fourth edition released in 2015 provides crucial technical updates to earlier versions, improving test accuracy through clarified specimen preparation, updated test voltage application, and enhanced graphical representations. It is primarily aimed at manufacturers, designers, and development engineers seeking reliable thermal performance data for winding wires used in electrical and electronic devices.

Key Topics

• Temperature Index (TI):
  The temperature index is a numerical value expressing the thermal capability of an insulating material in degrees Celsius. It helps characterize the endurance of enamelled or tape wrapped wires under elevated temperature conditions for a specified time (typically 20,000 hours).

• Test Methods:
  The standard describes how to prepare test specimens, including enamelled round wires and tape wrapped round or rectangular wires. Varnish impregnation and specimen holders are detailed to ensure consistent and repeatable conditions.

• AC Proof Voltage Tests:
  The procedure involves periodic electrical stress testing by applying an AC proof voltage to specimens, monitoring insulation degradation and failure times. This approach simulates real operating stresses to provide practical thermal endurance metrics.

• Specimens & Equipment:
  Detailed guidance is provided for specimen dimensions, twisting techniques for enamelled wire, and forming jigs for tape wrapped wires. High-resolution figures and tables specify proof voltage levels, exposure times, and test conditions.

• Data Analysis:
  Calculations focus on determining the time to failure and thermal endurance characteristics, using regression analysis to plot thermal endurance graphs and derive the temperature index. Annexes include instructions for regression calculation and correlation coefficients.

Applications

IEC 60172:2015 is essential for industries and professionals who work with electrical motors, transformers, inductors, and other equipment that rely on high-quality winding wires with reliable thermal durability.

• Wire Manufacturers: Use the test procedure to qualify and classify enamelled and tape wrapped wires, ensuring compliance with thermal endurance requirements.
• Design Engineers: Leverage temperature index data to select suitable winding wires for devices expected to operate at elevated temperatures.
• Quality Assurance: Implement routine testing to certify insulation performance consistency across wire batches.
• Research & Development: Utilize the method to innovate improved insulation materials and wire designs with enhanced thermal endurance.

Related Standards

IEC 60172:2015 references other key IEC standards that form the basis for thermal testing methodology and materials evaluation:

• IEC 60216-1: Electrical insulating materials – Thermal endurance properties – Part 1: Ageing procedures and evaluation of test results. This fundamental standard provides the underlying framework for the temperature endurance tests.

• IEC 60216-3: Electrical insulating materials – Thermal endurance properties – Part 3: Instructions for calculating thermal endurance characteristics. This complements IEC 60172 with guidance on interpreting test data and calculating temperature indices.

By adhering to IEC 60172 alongside these referenced standards, manufacturers and engineers ensure uniform testing practices and internationally recognized temperature index determinations for enamelled and tape wrapped winding wires.

Keywords: enamelled wire, tape wrapped winding wire, temperature index, AC proof voltage test, thermal endurance, insulation testing, IEC 60172, electrical insulating materials, winding wire temperature classification, wire thermal ageing