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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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 Establish the exposure temperatures and times in accordance with the instructions of 5. Copyright All the data, software and documentation set out in all British Standards and other BSI publications are the property of and copyrighted by BSI, or some person or entity that owns copyright in the information used such as the international standardization bodies and has formally licensed such information to BSI for commercial publication and use.
The thermal endurance characteristics are as derived in the calculations of 6. It is good practice to prepare additional specimens, or at least to provide a reserve of the original material batch from which such specimens may subsequently be prepared.
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If you need international and foreign standards from other Standards Development Organizations, hard copies can be ordered from our Customer Services team. Instructions for an adequate number of specimens are given in IEC The procedure is carried out numerically, and appropriate statistical tests are introduced.
The material specifications or the test standards will contain all necessary instructions for the preparation of specimens. If necessary, determine the initial value of the property as specified in 5.
The chosen property should reflect, in a significant fashion if possible, a function of the material in practical use.
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
The analysis of TI data is based on the assumption that there is a linear relation between the logarithm of the time to end-point and the reciprocal of the thermodynamic ageing temperature.
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. 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: This approach will provide comparisons among materials but bears a poorer relationship than item b to the property values required in normal service. This standard is concerned only with type 2.
These may be briefly expressed as follows see 3. This procedure is based on the assumption that the ageing rate of all specimens aged at one temperature is the same and can therefore be determined from the ageing rate of the property means of the successive groups tested.
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. Prepare a number of specimens following the instructions in 5.
If, for example, Group C has reached end-point nine cyclesGroups G, H and I would have received respectively six, seven and eight cycles at testing. The thickness is also important because the rate of ageing may vary with thickness. Failures at the end of the first ageing cycle cannot be accepted. Instructions for calculating thermal endurance characteristics using simplified procedures Guide for the statistical analysis of ageing test data Part 1: Ageing procedures and evaluation of test results 1 Scope This part of IEC specifies the general ageing conditions and procedures to be used for deriving thermal endurance characteristics and gives guidance in using the detailed instructions and guidelines in the other parts of the standard.
Related publications IEC For non-destructive tests, although Table 1 suggests constant cycle lengths, test times following a geometric series may be used.
On the same graph, plot the ageing temperatures, the times to end-point measured or hypotheticaland the mean times. Return specimens which have withstood the proof test to the oven from which they came, at the same temperature as before, and expose for a idc cycle. Except as permitted 602162- the Copyright, Designs and Patents Act no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means — electronic, photocopying, recording or otherwise — without prior written permission from BSI.
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Revisions Our Ic Standards and other publications are updated by amendment or revision. NOTE ied The above definition is not strictly compatible with the figure and also differs slightly from the definition in the second edition of IEC The general calculation 6216-2 outlined here and detailed in IEC are based on the principles set out in IEC NOTE 1 It is suggested that individual specimens be identified to simplify their return to the correct oven after each test.
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 62016-2 change in cycle time is made before the fourth cycle.
Instructions for calculating thermal endurance characteristics using simplified procedures. For the valid application of the standard, no transition, in particular no first-order transition should occur in the temperature range under study. For the determination of the initial value, see 5. However, for some materials very sensitive to the lec 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 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.
If this rule results in changes of mechanism for example, when a transformation point like melting or softening is exceededthen the kec exposure temperature will need to be limited. TEP was then abandoned, with the TI and HIC being reported in a way which indicated whether or not the statistical tests had been fully satisfied. In this way, 602216-2 required ageing of additional specimens in case of unforeseen complications will introduce a minimum risk of producing systematic differences between groups of specimens.
The thickness of specimens is in some cases specified in the list of property measurements for the determination of thermal endurance. A list of organizations represented on this committee can be obtained on request to its secretary.
Avenue Marnix 17, B – Brussels? The full experimental and 60216-22 procedures are given in Clause 5 and as far as 6.