1 - AS 60068.3.1-2003 ENVIRONMENTAL TESTING - BACKGROUND INFORMATION - SECTION ONE: COLD AND DRY HEAT TESTS
4 - PREFACE
5 - CONTENTS
7 - 1 Introduction
7 - 1.1 Reference ambient conditions
7 - 1.2 Devices without heat dissipation
7 - 1.3 Devices with heat dissipation
8 - 1.4 Ambient temperature
8 - 1.5 Surface temperatures
8 - 2 Reasons for the differing test procedures
8 - 2.1 Mechanisms of heat transfer
8 - 2.1.1 Convection
9 - 2.1.2 Thermal radiation
10 - 2.1.3 Thermal conduction
10 - 2.1.4 Forced air circulation
11 - 3 Test chambers
11 - 3.1 General
12 - 3.2 Methods of achieving the required conditions in the test chamber
12 - 3.2.1 Design of chambers for simulating the effect of free air condition
12 - 3.2.2 Design of chambers with forced air circulation
13 - 3.2.3 Emissivity coefficient of walls
13 - 3.2.4 Thermal characteristics of mounting devices
13 - 4 Measurements
13 - 4.1 Temperature
13 - 4.2 Air velocity
13 - 4.3 Emissivity coefficient
14 - Annex A - Effects of size of chamber on surface temperature of a specimen when no forced air circulation is used
16 - Annex B - Effect of airflow on chamber conditions and on surface temperatures of test specimens
16 - B.1 Calculation of the effect on airflow on specimen temperature and on temperature gradient in the chamber
20 - Annex C - Effect of specimen emissivity coefficient on temperature rise
21 - Annex D - Effect of wire termination dimensions and material on surface temperature of a component
22 - Annex E - Heat transfer calculations and nomograms
22 - E.1 Nomenclature
22 - E.2 Heat transfer by radiation
23 - E.3 Heat transfer by radiation and convection
24 - E.4 Correlation nomograms used in Test A and Test B
29 - Annex F - Thermal conductivities of common materials
30 - Annex G - Measurement of temperature
30 - G.1 General
30 - G.2 Methods using colour changing or melting effects
31 - G.3 Methods using infra-red sensors
32 - Annex H - Measurement of air velocity
33 - Annex J - Measurement of emissivity coefficient
33 - J.1 Introduction
33 - J.2 Radiation theory
34 - J.3 Practical applications of radiation theory
35 - J.4 Methods of measurements of emissivity coefficient
36 - J.5 Emissivity coefficient values
37 - J.6 Methods of increasing the emissivity of test chamber walls
41 - Annex K - General block diagram, cold and dry heat tests