Effect of Air Temperature, Barometric Pressure and Humidity on the Temperature Rise of Electric Apparatus

The tests which have been completed at the time of writing this paper are: First: The determination of the rise in temperature, all features being kept constant, except the temperature of the air and the surrounding walls. Second: The determination of the variation in rise of temperature, all features being kept constant, except the barometric pressure. Third: Some additional data were obtained showing variation of rise in temperature, all features being kept constant, except humidity of the surrounding air, but no difference in temperature rise due to variation in humidity was found. Tests are under way to determine the rise in temperature, keeping all features constant, except the temperature of the surrounding air, with a view to determining the effect of varying radiation. Results of the first set of tests are shown in Fig. 2. It will be seen that within the limits of error of observation and under the conditions of the test as made, a variation in the temperature of the air surrounding the coil does not affect the temperature rise. The slight difference in the amount of heat radiated from the coil at different temperatures, even though the surrounding walls were kept at air temperature, does not appear in the recorded results and must, therefore, be very small. Results of the second series of tests are shown in Fig.