IEC. Fourth edition. Electrical insulating materials – +41 22 02 11 Telefax: +41 22 03 00 E-mail: [email protected] Web: 标准 IEC 电气绝缘材料 耐热性 第1部分：老化程序和试验结果的 评定_电力/水利_工程科技_专业资料。标准 IEC 电气. this publication, including its validity, is available in the IEC Catalogue of IEC Electrical insulating materials – Properties of thermal endurance.
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This standard is concerned only with type 2. However, further guidance will be found in IEC Instructions for calculating thermal endurance characteristics using simplified procedures Guide for the statistical analysis of ageing test 62016-1 Part 1: In such cases, it may be possible to obtain an acceptable result by further testing at a lower temperature.
The procedure is carried out numerically, and appropriate statistical tests are introduced. Groups are tested as indicated in the table.
In cases of longer times, for example, the times given as requirements or recommendations in the text of this standard for example, 5 h for the minimum value of the longest time to end-point shall be increased in the ratio of the actual specification time to 20 h. A complicating factor is that the properties of a material subjected to thermal ageing may not all deteriorate at iev same ieec, and different end-points may be relevant for different applications.
The thickness is also important because the rate of ageing may vary with thickness.
标准 IEC 电气绝缘材料 耐热性 第1部分：老化程序和试验结果的评定_百度文库
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. Together with BS EN Prepare a number of specimens following the instructions in 5. It was felt to be much more important that assurance could be given that the difference between the calculated TI and its lower confidence limit was less than a specified value. This will have the effect of decreasing the extrapolation, which is one of the influences in determining the size of the confidence interval, and also make the errors associated with the non-linearity less serious.
If such material specifications are not available, a selection of properties and methods for the evaluation of thermal endurance is given in IEC NOTE The term Arrhenius is widely used and understood to indicate a linear relationship between the logarithm of a time and the reciprocal of the thermodynamic absolute or Kelvin temperature.
Our prices are in Swiss francs CHF. From these values, if necessary by interpolation see Figure 2obtain the time to end-point and calculate its logarithm as the y -value to be used in 6.
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A time to 6216-1 within the first ageing period shall be treated as invalid. End-points of proof tests are predominantly given in the form of fixed values of the property. Where there is no risk of ambiguity, either temperature groups or test groups may be referred to simply as groups.
On the same graph, plot the ageing temperatures, the times to end-point measured or hypotheticaland the mean times. Instructions for calculating thermal endurance characteristics using simplified procedures.
When the criterion is an absolute property level, n d is usually given the value of zero, unless reporting of the initial value is required. For materials in which a significant variation of properties with temperature or humidity is expected, unless otherwise specified, condition the specimens overnight in standard atmosphere B of IEC It may arise from inadequate experimental technique for example, oven temperature errors ; such non-linearity may be corrected by further testing.
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For graphical derivation and in some other cases the treatment of data may be simpler if the number 60216–1 specimens in each group is odd. NOTE 1 This table is intended primarily for cyclic proof testing and non-destructive tests, but may also be used as a guide for selection of suitable time intervals for destructive tests.
At the end of each cycle, remove all specimens from the oven. To reduce the uncertainties in calculating the appropriate thermal endurance characteristic, the overall temperature range of thermal exposure needs to be carefully selected, observing the following requirements if the required thermal endurance characteristics are for a projected duration of 20 Consequently, a material may be assigned more than one thermal endurance characteristic derived from the measurement of properties at different thicknesses.
Since processing conditions may significantly affect the ageing characteristics of some materials, it shall be ensured that, for example, sampling, cutting sheet from the supply roll, cutting of anisotropic material in a given direction, molding, curing, pre-conditioning, are performed in the iwc manner for all specimens. The application of conventional statistical tests, as set out in IECfulfilled this irc, resulting in the “confidence limit”, TC of TI, but the simple, single-point TI was found inadequate to describe the ie of materials.
In cases of oec specification times, the related times may be decreased in the same ratio if necessary. If the decision to ice the original test programme is taken after its completion, the duration of the complete procedure may become prohibitive. To find out more about becoming a BSI Subscribing Member and the benefits of membership, please visit bsigroup. The thermal endurance of an electrical insulating material is always given for a specific property and end-point.