Discussion on “inherent voltage relations in Y and delta connections” (Sorensen and Newton) and “harmonic voltages in currents in Y and delta-connected transformers,” (Clinker), Pittsfield, Mass., May 28, 1914. (see proceedings for May and June, 1914)

Waldo V. Lyon (by letter): The interesting fact that Mr. Clinker notes in regard to the possibility of a third-harmonic voltage existing between the lines of a three-phase circuit was observed by the writer some time since, and was used as the basis of one of the problems in a collection
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recently published by him. These third-harmonic components in the line voltages are equal but differ in phase by 120 degrees (third-harmonic scale) so that the circuit should respond to their influence in the same way that it would if sinusoidal voltages of three times the fundamental frequency were impressed upon it. This might produce serious results especially in transmission lines, if the harmonics were of sufficient magnitude. This phase difference in the third harmonic makes the resulting three-phase voltages dissimilar as Mr. Clinker points out. Their effective values, however, are equal.