IEC · IEC · IEC · IEC · IEC · IEC ; Show all». IEC Standard | Guide for the determination of thermal endurance properties of ekectrical insulating materials – Part 2: List of. IEC , Electrical insulating materials – Thermal endurance properties – Part 2: Determination of thermal endurance properties of electrical.
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NOTE 2 When extending the test program by submitting additional specimens to ageing at temperatures below the lower of the originally planned ageing temperatures, a temperature interval of 10 K and a cycle duration of 42 days for TI determination should be considered. Where the test criterion for non-destructive or proof tests is based kec the initial value of the property, this should be determined from a group of specimens of at least 602166-2 the number of specimens in each temperature group.
To achieve this, select the cycle length so that 60216–2 mean or ieec time to end-point is reached in about 10 cycles but not less than seven. Preview Abstract IEC 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 same manner for all specimens.
Related publications IEC Ageing at lower temperature s of one or two additional group s of specimens in case of suspected non-linearity can then be initiated immediately to produce the complete test data within a time limit which is still acceptable.
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For the determination of the initial value, see 5. If not, the assumption is a priori rejected, but, since in special cases it is possible to detect a statistically significant non-linearity which is of little practical importance, the calculations may, 602216-2 specified conditions, be continued in a modified way for details, see IEC If such material specifications are not available, a selection of properties and methods for the evaluation of thermal endurance is given in IEC If a time different from 20 h has been used for deriving the TI, the relevant time expressed in kh shall be stated, followed by kh.
If not, the thickness shall be reported. Throughout the rest of this standard the term “insulating materials” is always taken to mean “insulating materials and simple combinations of such materials”.
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We accept all major credit cards American Express, Mastercard and VisaPayPal and bank transfers as form of payment. The temperature extrapolation again shall not exceed 25 K. The IEC series has been developed to formalize these procedures and the interpretation of their results. uec
In such cases, it may be possible to obtain an acceptable result by further testing at a lower temperature. In this way, any required ageing of additional specimens in case of unforeseen complications will introduce a minimum risk of producing systematic differences between groups of specimens. Consequently, a material may be assigned more than one thermal endurance characteristic derived from the measurement of properties at different thicknesses.
The method ied evaluation of TI results is by the numerical procedure detailed in IEC together with a graphical presentation as shown in Figure 1.
Prepare a number of specimens following the instructions in 5. Users are responsible for its correct application. This led to the concept of the “Thermal Endurance Profile” TEPincorporating the temperature index, its variation with specified ageing time, and a confidence limit.
The following test report forms are related: It is good practice to prepare additional specimens, or at least to provide a 602162- of the original material batch from which such oec may subsequently be prepared. However, for some materials very sensitive to the humidity in the ovens, more reliable results are obtained when the absolute humidity in the ageing oven room is controlled and equal to the absolute humidity corresponding to standard atmosphere B according to IEC Calculation procedures and suitable restrictions have been developed to meet these circumstances and are given in detail in IEC Together with BS EN Ascending order in this standard implies that the data is ordered in this way, the first orderstatistic being the smallest.
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
However, further guidance will be found in IEC 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. This sixth edition cancels and replaces the fifth edition, published in Determination of thermal endurance properties of electrical insulating materials — Choice of test criteria IEC If the end-point is reached for more than one specimen during the first 6026-2, discard the group and test a further group, paying particular attention to any critical points of experimental procedure.
If the decision to extend the original test programme is taken after its completion, the duration of the complete procedure may become prohibitive.
Ic a few cycles, the remaining specimens can be placed in the oven and the points on the ageing curve property variation curve see Figures 2, 3 and 4which iev deemed necessary, determined.