At present, dry-type transformers generally choose low-voltage foil winding and high-voltage wire winding. Aluminum foil winding is the main choice for different transformers such as dry and low voltage in North America. Aluminum's maximum resistivity provides fewer eddy current losses within the winding, which reduces the likelihood of hot spots. Transformers with aluminum or copper winding have the same losses and performance.
Aluminum foil jumbo roll for transformers range from 0.2mm to 3.5mm in thickness and 10mm to 1600mm in width. The coils are wound on insulating materials such as paper, kraft paper, mylar or glass cloth. Aluminum foil has high electrical conductivity, good corrosion resistance and aesthetic appearance. Aluminum foil for transformer winding is an essential material in the production of transformers.
When foil winding, the aluminum foil must be tensioned to maintain a certain tension, and wound into a winding coil smoothly and flatly. The thicker the aluminum foil, the greater the tension required. The maximum tension of the foil winding machine is limited, exceeding the maximum tension of the machine is dangerous.
If the tension is too small, the wound coil is too loose, and the size requirements cannot be guaranteed. Therefore, this is not to say that you need to increase the thickness of the aluminum foil, because the transformer designer can comprehensively consider the thickness, cross-section, current density, temperature rise, etc. of the aluminum foil, instead of blindly adjusting the thickness to design and calculate the winding characteristics of the transformer.
The aluminum alloys for transformer winding are usually 1060, 1050, 1050A, 1060, 1070, 1070A and 1350. The temper is O. O represents the soft state, and numbers can be used to indicate the degree of softness and hardness, and the degree of annealing. The thickness is between 0.08-3.00 mm.
Alloys | 1050, 1350, 1060, 1070 |
Temper | O |
Thickness | 0.2-3.5 mm |
Width | 10-1600 mm |
Conductivity | 1050 O aluminum foil: over 60% ACS 1060 O aluminum foil: over 61.5% ACS 1070 O aluminum foil: over 62.7% ACS 1350 O aluminum foil: over 62% ACS |
1070 aluminum foil roll is an alloy with the highest purity in the pure aluminum series. It has the characteristics of high plasticity, low strength, excellent corrosion resistance, good electrical conductivity and thermal conductivity, and its electrical conductivity can reach more than 35.7 S/m. It is mainly used in transformer accessories.