BS 2011-3A & B:1977

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

To accompany BS 2011:Parts 2.1A and 2.1B. Effects of size of test chamber on surface temperature of a specimen when no forced air circulation is used. Effect of airflow on chamber conditions and on surface temperatures of test specimens. Effect of wire termination dimensions and material on surface temperature of a component. Measurement of temperature, air velocity and emissivity coefficient.