Current and voltage loci in 3-phase circuits part III: δ-Y connection

IT HAS been shown that the method of circular loci may be conveniently applied to obtain the variation of currents and voltages when self-impedances are changed in various types of circuits operated at constant frequency. Part I¹ dealt with this problem in a Y-Y connection and part II² in a Δ-Δ connection. In both of these papers current equations were given involving all the impedances and voltages of the most general types of Y-Y and Δ-Δ circuits and required only the substitution of numerical values to obtain the locus of any current or voltage existing in the system. The same treatment will now be applied to the Δ-Y connection.