Comparison of Dry-type Transformer Foil and Copper Foil

Aug 18, 2022

Comparison of technical performance of dry-type transformer coils made of aluminum foil and copper foil

Today, in Europe and the United States, Japan and South Korea first-class transformer production enterprises, have been widely used instead of copper or copper foil to low voltage and high voltage coil winding, its advantage has been the majority of users understand and appreciate.

Comparison of performance of dry-type transformer coils made of aluminium foil and copper foil:

1. Physical property of aluminum is lower than that of copper, but it has no effect on the use of dry-type transformers

In the winding coil, the coil inside and outside are equipped with glass fiber mesh, adopts the vacuum pouring method, coil without leaving voids and pores, glass fiber and resin together, and dry-type transformer aluminum foil and the insulating film is tightly integrated as a whole, these measures have been made up of aluminum foil the mechanical strength is lower than copper weakness. The aluminum foil high pressure coil is sufficient to resist the mechanical stress caused by sudden short circuit.

2., The conductivity of aluminum is smaller than copper, and the proportion is smaller than copper. It is more suitable for the conductor of dry type transformer coil.

Since the conductivity of aluminum is smaller than that of copper, aluminum must have a cross-sectional area of 1.64 times that of copper in order to obtain the same resistance. However, the density of aluminum is only 1/3 of copper, so when the same resistance value and transmission of the same capacity of electric energy, the quality of aluminum only needs 1/2 of copper. Because the quality of the aluminum coil is only half of that of copper, it can meet the requirement of light weight. Under normal circumstances, material costs can also be reduced, and the price performance ratio is much better than that of copper coil dry-type transformers.

3. Aluminum foil coil thermal stress performance is far better than copper foil or copper coil.

Because the thermal expansion coefficient of epoxy resin is 3.3 x 10 'K' as, while copper thermal expansion coefficient is 1.6 x 10 'K' as a, difference is more than doubled, while the Aluminum aluminum foil heat expansion coefficient of 2.3 x 10 'K' as, only small resin 1 * 10 'K' as. In daily operation, changes than the load, the dry coil with temperature change, conductor and resin with different coefficient of thermal expansion will produce thermal stress if the thermal stress is too large and repeatedly, often resulting in cracking resin. Compared with copper, the thermal expansion coefficient of thedry-type transformer aluminum foil is closer to the epoxy resin, and the thermal stress is reduced, thereby greatly improving the crack resistance and the safety of the dry type transformer, and prolonging the service life of the equipment.

Thus, with copper foil or copper wire winding dry transformer, high voltage coil than dry-type transformer aluminum foil winding easier to crack, the service life is relatively short.

Comparison of Dry-type Transformer Foil and Copper Foil

Aluminium Sheets

Aluminium Coils

Aluminium Foils

Aluminium Strips

Aluminium Circles

Coated Aluminium

Mirror Aluminum

Stucco Embossed Aluminum

Copper