Scaling of Machine Size as a Teaching Aid

There is a great educational value in solving a particular problem which relates the characteristics and parameter values of a machine to its size. By multiplying each linear dimension of a machine by a certain factor, its size is changed. The example used is a transformer, but the similarity to other devices is noted. The quantitative relations between size and characteristics are shown in the example. While these are themselves of some importance, it is the educational value of the problem which is featured. The author assigns such a problem to electrical engineering juniors and, in solving it, they must review or learn the theory associated with that kind of machine. More importantly, it leads to discussions with them on the characteristics and applications of the machine. Some of these are suggested in this paper.