• SN EN 60068-3-1 : 1999

    Current The latest, up-to-date edition.

    ENVIRONMENTAL TESTING - PART 3: BACKGROUND INFORMATION - SECTION 1: COLD AND DRY HEAT TESTS

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    Published date:  13-01-2013

    Publisher:  Swiss Standards

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    Table of Contents - (Show below) - (Hide below)

    1 Introduction
         1.1 Reference ambient conditions
         1.2 Devices without heat-dissipation
         1.3 Devices with heat-dissipation
         1.4 Ambient temperature
         1.5 Surface temperatures
    2. Reasons for the differing test procedures
         2.1 Mechanisms of heat transfer
    3. Test chambers
         3.1 General
         3.2 Methods of achieving the required
              conditions in the test chamber
    4. Measurements
         4.1 Temperature
         4.2 Air velocity
         4.3 Emissivity coefficient
    APPENDIX A - Effects of size of chamber on surface
                 temperature of a specimen when no forced
                 air circulation is used
    FIGURE 1 Heat dissipation per unit surface area of
                the test specimen at which the deviation
                between the surface temperature of the
                specimen in a very large chamber and in a
                smaller chamber reaches 5 deg C
    APPENDIX B - Effect of airflow on chamber conditions
                 and on surface temperatures of test-specimens
    FIGURE 2 Experimental data on the effect of airflow on
                surface temperature of a wirewound resistor
                - Radial airflow
    FIGURE 3 Experimental data on the effect of airflow on
                surface temperature of a wirewound resistor
                - Axial airflow
    FIGURE 4 Temperature distribution on a cylinder with
                homogeneous heat-generation in airflow of
                velocities 0.5, 1 and 2 m.s-1
    APPENDIX C - Effect of specimen emissivity coefficient
                 on temperature rise
    FIGURE 5 Comparison of the temperature rise as a
                function of heat-dissipation for thermal
                white and thermal black specimens subjected
                to an ambient temperature of 70 degree C
                in a chamber with thermal black walls.
                (Experimental values).
    APPENDIX D - Effect of wire termination dimensions and
                 material on surface temperature of a
                 component
    FIGURE 6
    APPENDIX E - Heat transfer calculations and nomograms
    FIGURE 7 Relationship between the surface temperature
                of the specimen and the heat dissipated per
                unit time at the ambient temperature
    FIGURE 8 Nomogram for evaluation of surface temperatures
                of the specimen at different ambient
                temperatures. Average specimen dimension = 0.2m,
                emissivity coefficient of the specimen = 0.7
    FIGURE 9 Nomogram for evaluation of surface temperatures
                of the specimen at different ambient temperatures.
                Average specimen dimension = 0.05 m, emissivity
                coefficient of the specimen = 0.7
    FIGURE 10 Relation between overtemperature and emissivity
                coefficient of the specimen
    APPENDIX F - Thermal conductivities of common materials
    APPENDIX G - Measurement of temperature
    APPENDIX H - Measurement of air velocity
    APPENDIX J - Measurement of emissivity coefficient
    FIGURE 11 Wien's displacement law
    FIGURE 12
    APPENDIX K - General block diagram, cold and dry heat tests
    FIGURE 13

    Abstract - (Show below) - (Hide below)

    Covers background information on basic environmental testing procedures - Cold and dry heat tests.

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    Document Type Standard
    Publisher Swiss Standards
    Status Current
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