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Nemzeti Fejlesztési Terv

Új Magyarország Fejlesztési Terv


Resin casting system to support transformer coils

Large-scale transformers have gaps between the iron core and the surrounding round coil. One of the causes of these gaps are the corrugated edges of the iron core, another cause is that with large dimensions, it is difficult to assemble the iron core precisely to the inner ring of the coil. Therefore, wooden rods previously adjusted in size by grinding are placed into the gaps. For work of this sort on a transformer hundreds of hours are required, but even this might not result in a perfect fitting. Misadjustment can lead to short circuits destroying the transformers.

The Transpolym technology developed by Kompozitor Ltd. applies composite material structures instead of wooden rods as follows:
Textubes, textile tubes of 15-45mm in diameter with a wall thickness of some tenth of millimeters, are placed into the gaps of the iron core. Then the transformer coil is quickly mounted on the iron core. Resin, prepared with a catalyzer, is poured into the broadening ends of the textile tubes that protrude the transformers. The tension in the resin presses the tubes against the surface of the iron core and the coil and hardens there irreversibly. Thus perfect fitting is achieved without any manual labour.


Kompozitor Kft. - Transpolym


Mechanical characteristics of the material:

Density: 2  kg/dm3  
Compressive strength (radial): 115  MPa -15°C
  110  MPa 20°C
  80  MPa 130°C
Flammability: hardly combustible  DIN 4102  


Dimensions and characteristics of Textube hose:

Internal diameter: 15-45  mm
Length: 1-5  m
Wall thickness: 0,15  mm
Tensile strength (chain): 60  MPa
Tensile strength (weft): 140  MPa
Operating temperature: -50-150  °C

Advantages of using Transpolym:

  • Save considerable (80%) working time
  • Exact fit
  • Great mechanical strength
  • Prevents the collapse of the coil
  • Operating temperature is between -50...+130°C


Since the launch of Transring in 1996 several rings have been mounted into the 200-320 MVA transformers of CG Electric Systems Hungary Zrt. (former Ganz Transelektro Zrt.) The same procedure is applied by Crompton Greaves Limited transformer factory in India.


Kompozitor Kft. - Transpolym