IEC 60851-2:2019 pdf download – Winding wires – Test methods – Part 2: Determination of dimensions.
3.2.1.2 Rectangular wire
The insulation shall be removed at the three places used for measurements in 3.2.5.2 by any method that does not damage the conductor. At each place one measurement of the two dimensions of the conductor shall be made.
The three single values shall be reported for each dimension of the conductor. The mean represents the conductor width or the conductor thickness respectively.
3.2.2 Out-of-roundness of the conductor
Out-of-roundness is the maximum value of the difference between the three readings if measured in accordance with 3.2.1.1.1, or the three readings of the conductor diameter at the cross-section if measured in accordance with 3.2.1.1.2.The out-of-roundness shall be reported.
3.2.3 Rounding of corners of rectangular wire
For the purpose of this test, a cross-section of the wire shall be prepared and then examined under a sufficient magnification.
Three straight pieces of wire shall be cast in a suitable resinous compound that will not affect the insulation. After curing, the colour of the resinous compound shall contrast with the colour of the insulation.
The specimen consisting of the three pieces of wire embedded in the cured resinous compound shall be cut at right angles to the length of the wire pieces, and the cross-section shall be carefully ground and polished by suitable means. The polished surface shall be examined under a magnification which allows a correct judgement of the rounding of corners.
It shall be reported how the arc merges into the flat surface of the conductor. Any sharp, rough and projecting edges shall also be reported.
3.2.4 Increase in dimension due to the insulation
3.2.4.1 General
The increase in dimension due to the insulation is the difference between the overall dimension and the conductor dimension.
3.2.4.2 Round wire
The measurement shall be made in accordance with 3.2.1.1 and 3.2.5.1. The difference between the overall diameter and the conductor diameter shall be reported as the increase in diameter.
3.2.4.3 Rectangular wire
The measurement shall be made in accordance with 3.2.1.2 and 3.2.5.2. The difference between the overall width and the conductor width shall be reported as the increase in width. The difference between the overall thickness and the conductor thickness shall be reported as the increase in thickness.
3.2.5 Overall dimension 3.2.5.1 Round wire 3.2.5.1.1 Nominal diameter up to and including 0,200 mm On a straight piece of wire， at three places 1 m apart, one measurement of the overall diameter shall be made. The three single values shall be reported. The mean value represents the overall diameter. 3.2.5.1.2 Nominal conductor diameter over 0, 200 mm On a straight piece of wire, at each of two places 1 m apart, three measurements of the overall diameter shall be made at points evenly distributed around the circumference of the wire. The six single values shall be reported. The mean value represents the overall diameter.
3.2.5.2 Rectangular wire On a straight piece of wire at each of three places at least 100 mm apart, one measurement shall be made of the two dimensions of the wire. Where the dimension of the specimen is greater than the diameter of the micrometer spindle, measurements shall be made both at the centre of the face of the specimen and over the edges. If these values differ, only the highest value shall be noted. The three single values shall be reported for each dimension of the wire. The mean values represent the overall width or the overall thickness respectively. 3.2.5.3 Bunched wire NOTE The method indicated below gives useful values in practice, but not an accurate overall diameter. The overall diameter is the width of a layer wound on a mandrel divided by the number of turns. The bunched wire shall be wound closely on a mandrel according to Figure 1 and under a tension in newtons, which is 65 times the total nominal cross-section of the conductors in square millimetres. The width of the layer shall be not less than 10 mm for bunched wires with overall diameters up to and including 0,5 mm，and be not less than 20 mm for larger diameters and shall be measured with a precision of 0,5 mm. One measurement shall be made. The overall diameter rounded off to 0,01 mm shall be reported.