Three phase T-connections are created by using two transformers with center taps on the primary and secondary windings. The "teaser" transformer is connected to the center tap of the "main" transformer. If the transformers have 10% taps available the output voltage can be made much more symmetrical than a standard open-delta configuration. Most dual voltage transformers can be connected in a T arrangement.
The Scott connection is a modified T connection which uses a standard center tapped "main" transformer and a special "teaser" transformer with a tap at 86.6% instead of at the center. This special tap location provides a "neutral" connection for a 3-phase 4-wire output. Most commercially built three phase transformers smaller than 15KVA are built using arrangement. Another common use is for creating a true 2-phase system from an existing 3-phase grid.
