Scott-T transformer
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A Scott-T Transformer (also called a Scott Connection) is a type of circuit used to derive two phase (2-φ) current from a three-phase (3-φ) source or vice-versa. The Scott connection evenly distributes a balanced load between the phases of the source.
Nikola Tesla's original polyphase power system was based on simple to build two-phase components. However, as transmission distances increased, the more transmission line efficient three-phase system became more prominent. Both 2-φ and 3-φ components coexisted for a number of years and the Scott-T transformer connection allowed them to be interconnected.
Assuming the desired voltage is the same on the two and three phase sides, the Scott-T transformer connection (shown below) consists of a center-tapped 1:1 ratio transformer T1 and an 86.6% (0.5√3) ratio transformer T2. The center tapped side of T1 is connected between two of the phases on the three phase side. Its center tap then connects to one end of the lower turn count side of T2, the other end connects to the remaining phase. The other side of the transformers then connect directly to the two pairs of a two-phase four-wire system.
