Paper Continuous Transposition Conductor (CTC) Most commonly used in the windings of power transformers, it consists of a number of rectangular thin-film insulated conductors made into assemblies, usually covered with a layer of insulating material. The number of conductors is usually odd (from 5 to 81) and is arranged side by side in two piles. A special tool alternately pushes the upper-left and lower-right wires onto the corresponding neighboring stacks so that each wire occupies every possible position in the continuously switched cable within a cycle. The length of a complete cycle of continuously switched cables depends on the minimum diameter of the transformer windings, the number of individual bars and their size.

Paper insulated copper conductors technical data:

Transposition number	5 – 81 (odd or even optional)
Maximum dimension	height 120 mm, width 26 mm (tolerance ± 0.05 mm)
Single conductor size	thickness a: 0.90 – 3.15 mm, width B: 2.50 – 13.00 mm (tolerance ± 0.01 mm)
The recommended width thickness ratio of a single conductor	2.0 < B / a < 9.0
The recommended coating thickness of enameled wire	0.08-0.12mm
The thickness of adhesive layer	0.03-0.05mm

Continuous transposition cable ctc Advantages
- The transformer is protected against unstable grids and the risk of short circuits.
- The PVA-EPOXY enameled rectangular wires used for the transposition conductors provide extreme bonding strength in the winding.
- The conductors in the winding become like solid beams and can withstand the strong electrodynamic stresses generated during a short-circuit event.
- No special handling is required by the user.


CTC PVA-EPOXY CPR has the following properties:
- Copper with high mechanical properties (typically the yield strength of CPR is 140 ÷ 0.1% of 250 MPa) - to withstand the electrodynamic stresses in case of short-circuit.
- Rectangular wires are coated with transformer oil-resistant polyvinyl acetal enameled wires.
- Enameled rectangular wires coated with epoxy resin (PVA-EPOXY) - a thin layer of non-sticky, cresol-free epoxy resin class B, which bonds the stranded wires together after heat treatment of the windings, forming a strong monolithic winding to withstand electrodynamic stresses in the event of short-circuit.
- The transposition conductors are wrapped with special insulating papers (hot upgraded, calendered, crepe), internally in contact with the stranded wires and externally wrapped to provide optimum geometry (well defined oil passages), thus giving the transformer good cooling properties.


Number of transpositions : 5 - 81 (odd or even optional)
Maximum dimensions : Height 120 mm, width 26 mm (tolerance ± 0.05 mm)
Single conductor dimensions : Thickness a : 0.90 - 3.15 mm, width B : 2.50 - 13.00 mm (tolerance ± 0.01 mm)
Recommended width-to-thickness ratio for single conductor : 2.0 < B / a < 9.0
Recommended coating thickness of enameled wire : 0.08 - 0.12 mm
Thickness of bonding layer : 0.03 - 0.05 mm