Single-phase induction-motor performance calculation

In the manufacture of electrical machines it is always desirable to calculate the performance of a machine before its construction to determine whether or not it will meet the specifications. The usual methods of predetermining performance involve the use of either a circle diagram or an equivalent circuit and since either of these methods involves considerable work there are always possibilities that errors may be introduced by slight mistakes in construction, measuring, etc. It was believed that if a method could be developed by which the quantities necessary for performance calculation could be given in the form of a set of curves considerable time might be saved provided that the accuracy so obtained was of the same degree as that given by other methods.