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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In the case of proof tests with incomplete data usually censored 602166-1 the medianit may be possible to obtain a sufficient increase in data group size by continuing the exposure until further test specimens have failed the proof test.
Before determining the property value, these specimens shall be conditioned by exposure to the lowest level of ageing temperature of the test see 5. A sequential procedure may also be justified where the envisaged accuracy of the evaluation requires additional specimens to be aged, for example, in the case where the thermal endurance relationship turns out to be non-linear.
Determination of thermal endurance properties of electrical insulating materials — Choice of test criteria IEC The following test report forms are related: For dated references, only the edition cited applies.
However, environmental conditioning, the influence of atmospheres other than air and immersion in liquids such as oil may be important, but these are not the concern of this standard. For undated references, the latest edition of the referenced document including any amendments applies.
Attention is drawn to the possibility that some of the elements of this document oec be the subject of patent rights. If not, the thickness shall be reported. Instructions for calculating thermal endurance characteristics using simplified procedures Guide for the statistical analysis of ageing test data Part 1: Accelerated ageing and test procedures were therefore required to obtain the necessary information.
Preview Abstract IEC Revisions Our British Standards and other publications are iwc by amendment or revision. For destructive tests, see 5.
For some materials, it is not possible to 602161- a time to end-point of less than h while retaining satisfactory linearity. The thermal endurance characteristics are as derived in the calculations of 6. A number of recommendations and suggestions, useful in establishing times and temperatures, will be found in Annex B.
In cases of shorter specification times, the related times may be decreased kec the same ratio if necessary. There are two alternative ways in which the end-point may be defined: In the application of this standard, it is assumed that eic practically linear relationship exists between the logarithm of the time required to cause the predetermined property change and the reciprocal of the corresponding absolute temperature Arrhenius relationship.
A complicating factor is that the properties of a material subjected to thermal ageing may not all deteriorate at the same rate, 602216-1 different end-points may be relevant for different applications. If the results do not show this, the period may be changed so that the median result may be expected in at least seven cycles preferably about 10 provided this change in cycle time is made before the fourth cycle. Ageing data of materials with different thicknesses are not always comparable.
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This difference is dependent on the scatter of the data points, the deviations from linearity in the regression analysis, the number of data points and the extent of extrapolation. It may arise from inadequate experimental technique for example, oven temperature errors ; such non-linearity may be corrected by further testing. This value might be selected with respect to usual service requirements.
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If end-point is reached in one of the Groups B — F, Groups G — I are immediately removed from the oven and tested after conditioning. TC – Evaluation and qualification of electrical insulating materials and systems rss. Where the test criterion for non-destructive or proof tests is based upon the initial ieec of the property, this should be determined from a group of specimens of at least twice the number of specimens in each temperature group.
Using Equations 46 to 50 of 6. The characteristic has now been made the subject of a new, independent standard in preparation.
If these expedients are not successful, it will be necessary to test at a temperature low enough for extrapolation not to be required. If the results show that this time to end-point is likely to be reached in about 10 periods of exposure, there is no need to alter the period of exposure originally selected.
If the decision to extend the original test programme is taken after its completion, idc duration of the complete procedure may become prohibitive.
The thickness is also important because the rate of ageing may vary with thickness. If the end-point is reached for more than ifc specimen during the first period, discard the group and test a further group, paying particular attention to any critical points of experimental procedure.
This does not necessarily imply a complete repeat of the experimental work, since it is possible if material is available to test further specimens and add the results to the original data. It is identical to IEC This, or other specified conditions, shall then be reported. The reference level may for example, be a mean value one parameter 06216-1 a line two parameters, slope and intercept.
This will have the effect ief 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. Instead, the trend of the thermal endurance relationship may be roughly estimated after the first or second failure at the lowest ageing temperature 6021-61 the original programme.
However, further guidance will be found in IEC This procedure is based on the assumption that the ageing rate of all specimens aged at one temperature is 60216- same and can therefore be determined from the ageing rate of the property means of the successive groups tested. This edition constitutes an editorial revision where the simplified method has been removed and now forms Part 8 of the EN Series: The material specifications or the test ieec will contain all necessary instructions for the preparation of specimens.
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For the valid application of the standard, no transition, in particular no first-order transition should occur in the temperature range under study. In order to carry out valid calculations, one or more further group s of specimens shall be aged at such a lower temperature as will enable the conditions to be met. Do you need a multi-user copy?