Heating of a D-C armature

THE purposes of these investigations were: (1) to determine what the maximum temperatures of the copper and iron were, and to compare those maximum temperatures with thermometer readings; (2) to measure the average of the maximum temperatures by resistance and to compare the results with the average secured from the maximum copper temperatures; (3) to measure the surface temperatures by means of a special contact thermocouple, and to compare those readings with those obtained by other means; (4) to measure the maximum commutator temperatures in several axial positions by the contact thermocouple, and to compare the results with thermometer readings; (5) to determine more accurate methods of calculating temperatures; and (6) to determine how to decrease the temperatures.