Aluminum Foil for Transformer Winding
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Aluminum Foil for Transformer Winding

What is the aluminum foil for transformer winding?

Transformer aluminum strip is the key raw material for manufacturing transformer winding, which is the strip formed by aluminum ingot pressing and rolling. The aluminum strip for transformer has high requirements for many technical indicators such as the conductivity, burr curling, side bending and surface quality of aluminum strip and foil.

The aluminum foil tape for transformer winding is also called the aluminum foil tape for transformer. It is widely used in the production of dry-type transformers, oil immersed transformers, high and low voltage transformers, etc.

dry-type transformers

oil immersed transformers

Common transformer foil alloy

Common alloys of transformer aluminum strip: 1060, 1050, 1070, 1350.

Temper: O

1060 transformer aluminum strip

The aluminum strip and foil for dry-type transformer are generally 1060 aluminum sheet and strip, with aluminum content of 99.6% or more. It is rolled into thin aluminum coils of different thickness and width by cold rolling mill, and then divided into aluminum strips of different width by longitudinal shear according to the different usage. It is mainly used for aluminum strips for reactors of dry-type transformers and large and medium-sized transformers.

1060 Transformer Aluminum Strip

Conductivity: surpass 61.5% ACS.

Edge treatment: straight edges with 90° angles, straight edges with chamfer, round edges treatment, no burr.

surface treatment: Smooth surface, uniform texture, clean and free from defects and scratches

1050 transformer aluminum strip

The aluminum content of 1050 can reach 99.5%. Like the 1060 transformer strip, it has high plasticity, corrosion resistance, good conductivity and thermal conductivity, but the conductivity of the 1050 is less than that of the 1060.

1050 Transformer Aluminum Strip

Conductivity: surpass 60% ACS.

Edge treatment: straight edges with 90°angles, straight edges with chamfer, round edges treatment,no burr.

surface treatment: smooth surface, uniform texture, clean and free from defects and scratches

1070 transformer aluminum strip

Compared with 1050, 1060, 1070 transformer aluminum strip, the aluminum content can reach 99.7%, and its conductivity is the highest among all common transformer aluminum strips. It has the characteristics of high plasticity, low strength, corrosion resistance, good conductivity and thermal conductivity, and is mainly used for transformer accessories.

1070 Transformer Aluminum Strip

Conductivity: surpass 62.7% ACS.

Edge treatment: straight edges with 90°angles, straight edges with chamfer, round edges treatment,no burr.

surface treatment: smooth surface, uniform texture, clean and free from defects and scratches

1350 transformer aluminum strip

1035 transformer strip is also often used as dry type transformer winding. It has the characteristics of 1050, 1060, 1070 and other 1000 series alloys, such as high plasticity, corrosion resistance, conductivity and thermal conductivity. However, it has low strength and is not easy to braze.

1350 Transformer Aluminum Strip

Conductivity: surpass 62% ACS.

Edge treatment: straight edges with 90°angles, straight edges with chamfer, round edges treatment,no burr.

surface treatment: Smooth surface, uniform texture, clean and free from defects and scratches

Specification of aluminum transformer foil

Chalco Aluminum can provide transformer aluminum strips of different specifications and sizes. Customers can choose different alloys and sizes according to their needs. It can also be customized.

Alloy 1060, 1050, 1070, 1350
Temper O
Thickness 0.2mm-3.0mm
width 20mm-1650mm
Inner diameter 150mm, 305mm, 405mm, 505mm
Outer diameter 700-1200mm

Performance and conductivity of transformer aluminum strip

The conductivity of transformer aluminum strip is an important basis to measure whether the transformer strip is qualified. Chalco Aluminum's transformer aluminum strip is superior to the industry standard.

Thickness Tensile strength
N/mm2(MPa)
Elongation
%
Bending 180 buckling inside radius Electric conductivity
% at 20°C
Over 0.2 to 0.5 55-95 20min. Close contact 61.5min.
Over 0.5 to 0.8 25min.
Over 0.8 to 1.5 30min.
Over 1.5 to 2.0 30min.
Over 2.0 to 3.0 35min.

Tolerance requirements for transformer aluminum strip

Thickness Tolerance in thickness Tolerance in width
Guaranteed value 20 to 300 Over 300 to 600 Over 600 to 1650
Over 0.2 to 0.5 ±0.02 ±0.3 ±0.5 ±1.0
Over 0.5 to 0.8 ±0.03
Over 0.8 to 1.3 ±0.04
Over 1.3 to 2.0 ±0.04
Over 2.0 to 3.0 ±0.05

Edge treatment for transformer aluminum strip

Chalco Aluminum can provide straight edges with 90°angles, straight edges with chamfer, round edges treatment.

The edges of Chalco’s transformer aluminum strip meet the following conditions:

Precision shearing: All dimensions (schematic)

Maximum burr size: 3% of the thickness or 0.05mm maximum

The edge quality shall comply to table below.
Sectional shapes of sheet edge
Accept accept
Reject reject

Three edge treatment processes for Chalco's transformer aluminum strip:

Edge rolling: use the vertical roller of a certain shape to press the edge burrs of the strip into the strip body.

Grinding: Use the grinding wheel or abrasive belt to repair the edge of the strip and remove the burrs.

Mechanical cutting: use the transformer aluminum strip trimming machine to cut the edge of the transformer strip. Envelope method and forming tool method can be used for mechanical cutting of full circle edges.

Advantage of Chalco's transformer aluminum strip

1. High conductivity

The transformer aluminum strip is made of high-quality pure aluminum, which has the characteristics of high conductivity.

2. The edges are smooth without burrs

The aluminum strip of the transformer has been specially edge treated, and the edges are smooth without burrs.

3. High aluminum purity

The transformer aluminum strip is made of high-purity aluminum, and the aluminum content can reach above 99.6%. It has better conductivity than other series of aluminum strips.

4. Good surface processing, uniform texture, clean and free from defects

The aluminum strip surface of the transformer is a rolled surface, which is well processed, uniform in texture, and free of scratches, metal and non-metallic inclusions, oil stains, local deformation and other defects.

5. Has high tensile strength and elongation.

Common issue

Comparison with copper strip

Comparison with Copper Strip

Aluminum coil winding transformers are becoming more and more popular. The aluminum strip of transformer is also used more and more on the transformer, and has been tested in practice. Compared with transformer copper strip, transformer aluminum strip winding has the following advantages:

Low price: compared with copper strip, aluminum strip of transformer is much cheaper, which is the biggest advantage of aluminum foil strip of transformer.

Light weight: The aluminum foil used for transformer has excellent flexibility, and can be made with a thickness of 0.08mm or less.

Small size: the conductivity of aluminum foil for transformer winding is up to 61%, while that of pure copper is only 58%. Aluminum foil with the same section is thinner than copper foil, which can reduce the thickness and volume of transformer winding.

High stability: the surface oxide film is easy to remove. The insulation strength is not affected when winding. The elongation is high, and it can be stretched for 2 mm without breaking.

Easy winding: it has the excellent plasticity and can be made into various shapes. Good adhesion between layers, is conducive to forming good coils through adhesive tape or backing paper.

Produce, inspect, transport, install, maintain and use according to certain standards. Both copper winding and aluminum winding transformers are safe and reliable.

Production process of transformer winding

  1. Raw materials are furnace heating to remove impurities;
  2. Cut into plates;
  3. Put the plate into the cold rolling mill for rough rolling;
  4. Put it into the hot rolling mill for finishing;
  5. Annealing;
  6. Plate shears;
  7. Packaging and transportation.

HS code for transformer winding

HS Code: 76069100.00

Hardness of aluminum foil for transformer winding

The typical Brinell hardness of the strip must be determined after annealing (Typical value of Brinell hardness: 18HB).

Why choose Chalco's transformer aluminum strip??

Chalco Aluminum is a large-scale modern aluminum processing enterprise integrating scientific research, processing and manufacturing. The company can produce 1-8 series aluminum coil strip products, and the transformer aluminum strip is the key product of the company. Customers include ABB, Siemens, Legrand, Toshiba, etc.

Transportation and service

Transportation and Service
Packing Wooden pallet: standard export package, no fumigation;
Tray size: 1.1m × 1.1 m × 0.8 m;
Gross weight: 1 ton;
4 pallets/20'FCL; 8 pallets/40 'FCL
or according to customer requirements.
Wooden case: standard export package with fumigation certificate, which can avoid any potential damage during transportation.
Term of payment 30% TT deposit and 70% balance before shipment, 100% LC at sight
Delivery time 7-10 business days
Minimum order quantity 5 tons
Port of shipment Shanghai Port, Qingdao Port, Guangzhou Port, etc.
Sample Aluminum strip sample of transformer can be provided
Brand Customizable
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