AFT » Commercial Benefits - Technical Benefits - Application

The Aluminium foil wound transformer is a significant Value Engineering break through in the transformer industry. The replacement of conventional copper wire by Aluminium Foil in transformer coils results in an increase in its reliability and reduction in overall material costs by as much as 15 to 20 per cent.

This technology has been successfully used in the manufacture of our KRYKARD power conditioners since 1993. The reliability of the technology is amply proven in over 2,00,000 AFTs functioning efficiently since 1993.

The commercial benefits of AFTs over conventional Copper wire wound transformers are:

• Reduced material costs: Weight for weight, Aluminium is twice as conductive as Copper. An Aluminium conductor of half the weight can carry the current carried by a Copper conductor. A cost reduction of 10 – 15% is achievable by substituting Copper conductor with Aluminium.
• Stable material costs: Aluminium is abundantly available in India and prices are stable in comparison with Copper.
• Lower handling & freight costs: AFTs are lighter than Copper wire wound transformers by about 10 – 15% resulting in lower handling & freight costs.

The technical benefits of AFTs over conventional Copper wire wound transformers are:

• Compact size and reduced weight: Even while using a larger volume of conductor, the foil design facilitates higher accommodation of the window area and so, there is no increase in the size of transformers. Aluminium Foil Transformers will thus be compact and lighter.
• Greater insulation reliability: In a foil wound transformer, the voltage gradient between layers is the voltage gradient per turn.  This reduces the strain on the inter-layer insulation and increases reliability.
• Increased thermal stability and higher short-term over load capacity: As the layer type winding in Aluminium Foil provides a larger surface area for cooling, the winding achieves thermal stability in a very short time.  Also the specific heat of Aluminium is greater than copper, helps in preventing burn-outs due to hot spots and makes the transformer withstand higher short-term over loads.
• Higher surge withstanding capability: The inter layer capacitance of a Aluminium Foil winding is greater than the winding made out of wire. The surge developed in an Aluminium Foil transformer is equally distributed among all turns in less time than wire wound transformers, giving them higher surge withstanding capability.
• Enhanced ability to withstand short circuit currents: Improved balance between magnetic fluxes of primary and secondary windings enhances the capability of Aluminium Foil transformers to withstand short circuits, rendering them superior to wire wound or strip wound transformers.
• Reduced impact of harmonics and high frequency on the design of transformers: The ratio of surface area to conducting area being higher in foils than wire, heat generated by skin effect is reduced.  This in turn reduces the need to de-rate conductors, used in the application of handling currents of higher frequency or containing a high percentage of higher order harmonics.