Polyphase Alternating Current Circuits

Abstract

A polyphase system is one which comprises two or more sets of supply voltages which have a fixed phase angle difference between them. In the two-phase system (figure 8.1a) the phase difference is 90°, and in the three-phase system (figure 8.1b) it is 120°. Although the three-phase system is the most popular, some installations use six-, twelve- and twenty-four-phase systems.