Foreword
Clause
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 of 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
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 deg 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
Ts of the specimen and the heat dissipated P
per unit time at the ambient temperature Ta
Figure 8 Nomogram for evaluation of surface
temperatures of the specimen Ts at different
ambient temperatures Ta. Average specimen
dimension a = 0.2 m, emissivity coefficient
of the specimen epsilon 2 = 0.7
Figure 9 Nomogram for evaluation of surface
temperatures of the specimen Ts at different
ambient temperatures Ta. Average specimen
dimension a = 0.05 m, emissivity coefficient
of the specimen epsilon 2 = 0.7
Figure 10 Relation between overtemperature and
emissivity coefficient epsilon 2 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 Relation between (M0 lambda)/Ms and lambda.T
Appendix K - General block diagram, cold and dry heat
tests
Figure 13