IEC 60172:2020 pdf download

IEC 60172:2020 pdf download.Test procedure for the determination of the temperature index of enamelled and tape wrapped winding wires
1 Scope
This International Standard specifies, in accordance with the provisions of IEC 60216-1, a method for evaluating the temperature index of enamelled wire, varnished or unvarnished with an impregnating agent, and of tape wrapped round and rectangular wire, in air at atmospheric pressure by periodically monitoring changes in response to AC proof voltage tests. This procedure does not apply to fibre-insulated wire or wire covered with tapes containing inorganic fibres. NOTE The data obtained according to this test procedure provide the designer and development engineer with information for the selection of winding wire for further evaluation of insulation systems and equipment tests.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 60216-1, Electrical insulating materials – Thermal endurance properties – Part 1: Ageing procedures and evaluation of test results IEC 60216-3, Electrical insulating materials – Thermal endurance properties – Part 3: Instructions for calculating thermal endurance characteristics
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:  IEC Electropedia: available at http://www.electropedia.org/ ISO Online browsing platform: available at http://www.iso.org/obp 3.1 temperature index TI number which permits comparison of the temperature/time characteristics of an electrical insulating material, or a simple combination of materials, based on the temperature in degrees Celsius which is obtained by extrapolating the Arrhenius plot of life versus temperature to a lifetime of 20 000 h 3.2 specimen failure time number of hours at the exposure temperature that have elapsed at the time a specimen fails the proof test 3.3 time to failure number of hours to failure calculated from the specimen mean value or logarithmic mean value failure times for a set of specimens at one exposure temperature, in accordance with 8.2
4 Summary of procedure
A set of specimens in accordance with Clause 5 is subjected to a testing cycle. This cycle consists of a heat-exposure period at a temperature given in Clause 6, followed by a proof voltage test at room temperature in accordance with Clause 7. This cycle is repeated until a sufficient number of specimens has failed. The time to failure is calculated in accordance with Clause 8. The test is carried out at three or more temperatures. A regression line is calculated in accordance with 8.4 and the time to failure values plotted on thermal endurance graph paper as a function of the exposure temperature. The temperature in degrees Celsius, corresponding to the point of intersection of the regression line with the ordinate of 20 000 h endurance represents the temperature index of the winding wire under test.
5 Test specimens
5.1 Preparation 5.1.1 Enamelled non-tape wrapped round wire This procedure applies to enamelled round wires that are not tape wrapped. The thermal index can be determined by evaluating enamelled non-tape wrapped round wire with a nominal conductor diameter of 0,224 mm up to and including 2,65 mm. NOTE For round enamelled winding wires, experience has shown that nominal conductor diameters of 0,800 mm up to and including 1,60 mm are generally found convenient to handle and test. Wires with a nominal conductor diameter between 0,280 mm and 0,500 mm are permitted for use when the specification range of diameters is limited to 0,500 mm and finer. The grade of insulation used for determining the thermal index shall be grade 2 or grade 2B for self-bonding winding wires.