Continuously Transposed Conductor Cu (Copper CTC)

Continuously Transposed Conductor (or CTC) is the most used for power transformer windings. 
It consists of a group of enameled rectangular wires, usually with PVF enamel, which are stranded to create a rectangular rope.
In this group each strand successively and repeatedly takes on every possible position inside the whole conductor cross-section. 
The strands as a whole are wrapped with pure cellulose paper tapes.
This conductor is used for manufacturing low losses windings for electric machines. 
 
The growth of the power of electrical machines has increased the need of more efficiency. 
Regarding the different losses in the transformer, the use of CTC windings has improved this important characteristic of transformers design. 
The adoption of CTC brings great advantage in reduction of eddy current losses, particularly at the end of the winding. 
In addition it is possible to have a considerable increase in the space factor of the winding, due to the very small thickness of the insulation of the single conductors and getting a more uniform distribution of the temperature throughout the whole winding.