Continuously Transposed Conductor Without Paper is one of CTC Winding that is composed of serveral enameled flat copper wire for HV systems. The different type of enamels provide the insulation of each single conductor. The number of conductors can be an odd number from 5 up to 81. Transposed cable can be divided into paper insulated conductor and CTC without paper.
The main CTCs’ feature is that each conductor, successively and repeatedly, is transposed through every possible position in the entire conductor cross-section, in a rotating movement. During the transposition, each single conductor stays parallel to the others, without any twist.
Manufactured without paper, using a tie cord replacing
NETTING TAPE: the polyester net is used in the place of tie cord.
Three insulation thermal classes are available: Inveform 120ºC, Inveterm 180ºC and Invemid 220ºC. Enamelled single rectangular conductors are produced according to the standards IEC 60851 test methods, IEC60317-0-2 General Requirements, IEC 60317-18 (INVEFORM 120) and IEC 60317-28 (INVETERM 180) and NEMA-MW 38C (INVEMID 220).
The bondable over coating allows adhesion of the strands after heat treatment at 120°C 24 h. The bondable over coat has a shelf life up to 8 months (or up to 6 months for treatment at 110°C 48 h) for storage at temperature not greater than 32°C. Good bonding result is achieved in laboratory specimens after treatment at 130°C for 16 hours or 120°C for 24 hours or 100°C for 48 hours
When ordering Continuously Transposed Conductors, the following information are requested:
- number of strands and their nominal dimensions
- type of copper and type of enamelled wires (with or without bondable epoxy varnish)
- minimum winding diameter
- total paper thickness and paper type
- interleaving paper and its thickness
- required length and type of drum
