2.2.1 Positive Phase Sequence

In case of a positive phase sequence, voltage on all the three lines of three-phase supply cycles through 360° where phase L2 lags phase L1 by 120° and phase L3 lags phase L1 by +240°. The sequence L1 – L2 – L3 is termed as a positive phase sequence.

Figure 2-1 ‘a’ shows the positive phase sequence of three-phase supply, where the phases L1, L2, and L3, attain their respective peak voltages periodically, one after the other in the sequence.