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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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. In cases of shorter specification times, the related times may be decreased in the same ratio if necessary. For the valid application of the standard, no transition, in particular no first-order transition should occur in the temperature range under study.
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Avenue Marnix 17, B – Brussels? Apply the appropriate test to each specimen and then return the group to the oven from which they came, at the same temperature as before, and expose for a further cycle.
The IEC series has been developed to formalize these procedures and the interpretation of their results. 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 ied 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.
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. Using Equations 46 iiec 50 of 6. Except as permitted under 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.
In all cases, ageing shall be continued until more than one-half of the test specimens in each group have failed to pass the proof test. However, the planned number of groups of specimens at each temperature see 5. 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.
A simplified procedure, requiring a limited subset of the following tests is reported in IEC The application of conventional statistical tests, as set out in IECfulfilled this requirement, resulting in the “confidence limit”, TC of TI, but the simple, single-point TI was found inadequate to describe the capabilities of materials. This procedure is based on the ice 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.
Information on standards We can provide you with the knowledge that your organization needs to succeed. Place one group for exposure in each of 602162- ovens complying with 5. Consequently, a material may be assigned more than one thermal endurance characteristic derived from the measurement of properties at different thicknesses.
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NOTE 1 This table is intended primarily for cyclic proof testing and non-destructive tests, but 602162 also be used as a guide for selection of suitable time intervals for destructive tests.
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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The British Standards Institution The time interval between tests of groups should be planned so that the results of at least two groups of specimens are available before the mean time to end-point, and at least one after: If such a method cannot be found, an international, national, or institution standard, or a specially devised method should be used, and in that order 60261-2 preference.
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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.
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The validity of the model is, therefore, not dependent on the more stringent condition of a linear relationship between the level of the diagnostic property and the degree of molecular change. In the official version, for Bibliography, the following notes have to be added for the standards indicated: To find out more about becoming a BSI Subscribing Member and the benefits of membership, please 6021-2 bsigroup.
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. It is not necessary for all 60126-2 to be equal in size or for equal numbers to have failed. Out of this arose the concept of the temperature index TI as a single-point characteristic based upon accelerated ageing data. After each removal, allow the group of specimens to cool to room temperature unless otherwise specified.
If not, the thickness shall be reported. Test the specimens and plot the results and the arithmetic mean of the results or a suitable transform thereof against the logarithm of exposure time as given in 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.
This led to the concept of the “Thermal Endurance Profile” TEPincorporating the temperature index, its kec with specified ageing time, and a confidence limit. The value of its square is between 0 no correlation and 1 complete correlation. If such information is not available, preliminary screening tests may be performed to produce a forecast of the value of TI. The general calculation procedures outlined here and detailed in IEC are based on the principles set out in IEC In the case of destructive tests 6.
In ied 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.
60216–2 are ISO and ISO respectively, which use less rigorous statistical procedures and more restricted experimental techniques.
Groups are tested as indicated in the table. Do you need a multi-user copy? The first assumption is tested by the so-called Fisher test F -test. In this case, cycle times of 56 days, or even more, may be required.