Abstract :
H. C. Specht (by letter): The calculation method shown by Mr. West will, without doubt, interest all motor designers. The way of demonstrating the different fluxes gives a very clear picture which can be easily understood. On the other hand, such a method of calculation without the use of diagrams and saturation curves seems to me rather complicated for routine design work, in spite of the fact that the effect of short-circuit current under the brushes and iron losses have been neglected. It is also assumed that all m. m. f. and fluxes are sinusoidal, which does not often correspond to the type of winding usually employed in a commercial motor. Another assumption is that of constant reluctance, whereas this will vary inversely with the saturation, which will have a very marked effect on the characteristics of the motor at overloads and when starting.
