Three-phase transformers are connected in delta or wye configurations. A wye-delta transformer has its primary winding connected in a wye and its secondary winding connected in a delta (see figure 1-1). A delta-wye transformer has its primary winding connected in delta and its secondary winding connected in a wye (see figure 1-2).
Figure 1-1: Wye-Delta connection
Figure 1-2: Delta-Wye connection
Figure 1-1: Wye-Delta connection
Figure 1-2: Delta-Wye connection
