Effect of room temperature on temperature rise of motors and generators

The paper gives the results of certain special tests on motors and an investigation of certain commercial tests on motors and generators, with the purpose of obtaining data which would indicate the effect of room temperature on temperature rise of motors and generators. The special tests were made in a room the temperature of which could be controlled. The general tendency of these tests was toward a higher rise at the cold room temperature, but the results were not entirely consistent, and hence no general rule could be found for applying a correction. Curves and data are given showing the methods used and the results obtained, from which the following conclusions were drawn: 1. The present correction rule is wrong and should be abrogated. 2. The considerable variations obtained show the difficulty of making a rule that will include all types of machines or even all parts of the same machine. 3. A consideration of the total temperature obtained when working under normal conditions in the maximum room temperature, is of more importance than the rise of temperature. 4. Further tests leading to the determination of a correct rule, if possible, are desirable.