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 The ageing graph is formed by plotting the value of property or a suitable transform of its value against the logarithm of the exposure time. The procedure is carried out numerically, and appropriate statistical tests are introduced.
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Continue the cycles of temperature exposure, cooling and application of the test until the average measured value for the specimens in the group has reached the end-point specified and provided at least 60126-2 point beyond the end-point. These further tests may be at lower or intermediate temperatures but should not generally be at higher temperatures than originally selected. Some physical properties are sensitive even to minor variations of specimen thickness.
A simplified calculation procedure is described in IEC This standard is concerned only with type 2.
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
This model is valid when the selected end-point of the diagnostic property is correlated with a particular degree of molecular change in the material which is subject to ageing. Diagnostic procedures may be non-destructive or destructive determinations of a property or potentially destructive proof tests see 5. In this case, cycle times of 56 days, or even more, may be required. Together with BS EN Very long specification times may also lead to non-linearity see also Annex A.
In the application of this standard, it is assumed that a 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. Place one group for exposure in each of the ovens complying with 5. Avenue Marnix 17, B – Brussels? In such cases, it may 602162- possible to obtain an acceptable result by further 602162- at a lower temperature.
This edition constitutes an editorial revision where the simplified method has been removed and now forms Part 8 of the EN Series: 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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If, for example, Group C has reached end-point nine cyclesGroups G, H and I would have 600216-2 respectively six, seven and eight cycles at testing. Unless otherwise specified, IEC shall apply. To achieve this, select the cycle length so that the mean or median time to end-point is reached in about 10 cycles but not less than seven. In either case, the specimen preparation technique should be carefully examined.
Note 2 to entry: NOTE 1 It is suggested that individual specimens be identified to simplify their return to the correct oven after each test. 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.
Early results of the ageing test may motivate ief adjustment of ageing cycles or additional ageing temperatures.
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. The knowledge embodied in our standards has been carefully assembled in a dependable format and refined through our open consultation process. This sixth edition cancels and replaces the fifth edition, published in The regression analysis 6021-2 slope and intercept of the thermal endurance graph and the tests for deviations from linearity shall be as in 6.
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In the application of this standard, it is assumed that a practically linear relationship exists between the logarithm of the time required to cause the predetermined property change and idc reciprocal of the corresponding absolute temperature Arrhenius relationship. It is advisable to distinguish between: If either of these conditions is not met, the value of TI cannot be reported.
However, 6216-2 some materials very sensitive to the humidity in ied 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 NOTE 60261-2 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.
It is not necessary for all groups to be equal in size or for equal numbers to have failed. For further information, email bsmusales bsigroup.
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.