Scott-T transformers allows to supply two-phase receivers or two groups of single-phase receivers with classic three-phase network. Maintaining the symmetry of the secondary side load ensures a symmetrical load on the supply network.
The most common three-wire two-phase system has two balanced circuits with approximately the same rated current and a neutral conductor approximately 1.41 times the rated current.
Voltages are 90 deg. out of phase.
The Scott circuit (Scott-T) transforms three-phase mains circuit into two-phase outpu using two appropriately designed single-phase transformers. The first transformer (teaser transformer) is connected between one of the phases and the primary winding tap of the main transformer. The second transformer (so-called main transformer) is connected between the other two phases.
The secondary windings of the Scott system ensure a symmetrical load of the three-phase network, when both windings are symmetrically loaded with the same value of the rated current. Non-symmetrical load of the transformer output results in an unbalanced load in the supply network.
It is also possible to load both secondary windings of the Scott circuit with two groups of single-phase loads. However, it should be remembered that it is crucial that both windings are evenly loaded with the same current, which will ensure symmetry of the load in the three-phase network. Loading only one secondary winding of the Scott system with a single-phase receiver will result in a significant asymmetry of the supply network load and a decrease in the efficiency of the entire system.