Short-duration temperature testing of elecrical machines

A method for the rapid determination of the temperature rise and the time constant of electrcal machinery and apparatus, based on the exponential heating and the Hak curves, is described. Tests are produced showing that there is a satisfactory agreement between the figures and curves of the graphical method by shor-duration tests and those obtained by measurement from long heat-runs. The theory of the Hak curve is discussed in the Appendix and its calcualtion fully explained. Finally a table of ¿Calculations and Plottings for the standard Hak Cuve¿ is given from which this curve can be constructed and the method immediately applied.