External heat transfer from cylindrical self-cooled electric equipment

IN ADDITION to the usual electromagnetic and electrical limitations, the performance of electric equipment is dependent on its ability to dissipate its losses and still maintain safe component temperatures. For forced-cooled equipment, such as blast-cooled generators, a continuous flow of coolant is provided to carry away practically all of the heat. Since only one method of heat transfer need be considered, techniques are available which can be used to predict the cooling performance for any set of cooling conditions encountered in aircraft.1 For self-cooled equipment, however, the heat transfer picture is much more complicated. Heat may be dissipated by natural or forced convection to the surrounding air, by radiation to surrounding objects, and by direct conduction to objects with which it comes in contact.